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DuPont Delaware River Study Phase I Characterization of Ecological Stressors In the Delaware Estuary February 2007
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Characterization of Ecological Stressors in the Delaware Estuary

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Page 1: Characterization of Ecological Stressors in the Delaware Estuary

DuPont Delaware River Study Phase I

Characterization of Ecological Stressors In the Delaware Estuary

February 2007

Page 2: Characterization of Ecological Stressors in the Delaware Estuary

2/15/07 iCharacterization of Ecological Stressors

Table of Contents

List of Tables.................................................................................................................. v

Tables (con’t) ................................................................................................................ vi

List of Figures.............................................................................................................. vii

Figures (con’t)............................................................................................................. viii

Figures (con’t)................................................................................................................ x

Acronyms and Abbreviations...................................................................................... xi

Acronyms and Abbreviations (con’t)......................................................................... xii

Unit Conversions........................................................................................................ xiii

Section 1. Introduction...........................................................................................1-1

1.1 Background .............................................................................................. 1-11.2 Objectives of Report................................................................................. 1-31.3 Study Area ............................................................................................... 1-4

Section 2. Approach and Methods........................................................................2-1

2.1 Data and Information Search and Compilation........................................ 2-12.2 Bibliography Development ....................................................................... 2-32.3 Delaware Estuary Zones of Study ........................................................... 2-32.4 Data Review and Presentation ................................................................ 2-4

Section 3. Sources and Types of Stressors in the Delaware Estuary ...............3-1

3.1 Stressor Definition, Categories, and Interactions .................................... 3-13.2 Stressor Sources...................................................................................... 3-3

3.2.1 Dredging and Channelization...................................................... 3-33.2.2 Dredged Material Disposal.......................................................... 3-33.2.3 Maritime Operations.................................................................... 3-33.2.4 Recreational Boating................................................................... 3-43.2.5 Commercial and Recreational Fishing........................................ 3-43.2.6 Dams and Weirs.......................................................................... 3-43.2.7 Urban Development .................................................................... 3-43.2.8 Agricultural Land Use.................................................................. 3-53.2.9 Shoreline Alteration..................................................................... 3-53.2.10 Drought and Water Withdrawal................................................... 3-53.2.11 Municipal Wastewater Discharges.............................................. 3-53.2.12 Combined Sewer Overflows ....................................................... 3-63.2.13 Stormwater.................................................................................. 3-6

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3.2.14 Electric Generating Facilities ...................................................... 3-63.2.15 Industrial Facilities....................................................................... 3-73.2.16 Accidental Spills/Releases.......................................................... 3-73.2.17 Sediments ................................................................................... 3-83.2.18 Atmospheric Deposition .............................................................. 3-8

3.3 Stressor Inventory .................................................................................... 3-8

Section 4. Characteristics of Regional Stressors in the Delaware Estuary......4-1

4.1 Physical Stressors.................................................................................... 4-14.1.1 Water Volume ............................................................................. 4-1

4.1.1.1 Sources ....................................................................... 4-24.1.1.2 Metrics ......................................................................... 4-24.1.1.3 Temporal and Spatial Trends...................................... 4-24.1.1.4 Data / Information Gaps and Uncertainties ................. 4-4

4.1.2 Water Temperature ..................................................................... 4-44.1.2.1 Sources ....................................................................... 4-44.1.2.2 Metrics ......................................................................... 4-54.1.2.3 Temporal and Spatial Trends...................................... 4-5

4.1.2.3.1 Temporal Trends....................................... 4-54.1.2.3.2 Spatial Trends........................................... 4-6

4.1.2.4 Data / Information Gaps and Uncertainties ................. 4-64.1.3 Salinity......................................................................................... 4-7

4.1.3.1 Sources ....................................................................... 4-74.1.3.2 Metrics ......................................................................... 4-74.1.3.3 Temporal and Spatial Trends...................................... 4-74.1.3.4 Data / Information Gaps and Uncertainties ................. 4-9

4.1.4 Suspended Solids ....................................................................... 4-94.1.4.1 Sources ..................................................................... 4-104.1.4.2 Metrics ....................................................................... 4-104.1.4.3 Temporal and Spatial Trends.................................... 4-104.1.4.4 Data / Information Gaps and Uncertainties ............... 4-11

4.1.5 Sedimentation ........................................................................... 4-124.1.5.1 Sources ..................................................................... 4-124.1.5.2 Metrics ....................................................................... 4-124.1.5.3 Temporal and Spatial Trends.................................... 4-124.1.5.4 Data / Information Gaps and Uncertainties ............... 4-13

4.1.6 Barriers to Fish Access ............................................................. 4-134.1.7 Habitat Loss .............................................................................. 4-14

4.1.7.1 Sources ..................................................................... 4-154.1.7.2 Temporal and Spatial Trends.................................... 4-16

4.1.7.2.1 Pennsylvania........................................... 4-164.1.7.2.2 Delaware................................................. 4-174.1.7.2.3 New Jersey ............................................. 4-174.1.7.2.4 Tributaries ............................................... 4-18

4.1.7.3 Data / Information Gaps and Uncertainties ............... 4-194.2 Chemical Stressors ................................................................................ 4-19

4.2.1 Petroleum, PAHs, and Related Compounds ............................ 4-214.2.1.1 Sources ..................................................................... 4-224.2.1.2 Metrics ....................................................................... 4-234.2.1.3 Temporal and Spatial Trends.................................... 4-23

4.2.1.3.1 Sediment ................................................. 4-234.2.1.3.2 Water....................................................... 4-24

4.2.1.4 Data / Information Gaps and Uncertainties ............... 4-254.2.2 PCBs ......................................................................................... 4-26

4.2.2.1 Sources ..................................................................... 4-26

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4.2.2.1.1 PCB TMDL Development........................ 4-274.2.2.1.2 Source Types and Loadings ................... 4-274.2.2.1.3 Relative Source Strength ........................ 4-28

4.2.2.2 Metrics ....................................................................... 4-294.2.2.3 Temporal and Spatial Trends.................................... 4-29

4.2.2.3.1 Sediment ................................................. 4-294.2.2.3.2 Water....................................................... 4-304.2.2.3.3 Tissue...................................................... 4-30

4.2.2.4 Data Gaps / Information and Uncertainties ............... 4-314.2.3 Dioxins and Furans ................................................................... 4-324.2.4 Pesticides.................................................................................. 4-32

4.2.4.1 Sources ..................................................................... 4-334.2.4.2 Metrics ....................................................................... 4-334.2.4.3 Temporal and Spatial Trends.................................... 4-33

4.2.4.3.1 Sediment ................................................. 4-334.2.4.3.2 Water....................................................... 4-344.2.4.3.3 Tissue...................................................... 4-34

4.2.4.4 Data Gaps / Information and Uncertainties ............... 4-354.2.5 Metals........................................................................................ 4-36

4.2.5.1 Sources ..................................................................... 4-364.2.5.2 Metrics ....................................................................... 4-374.2.5.3 Temporal and Spatial Trends.................................... 4-37

4.2.5.3.1 Sediment ................................................. 4-374.2.5.3.2 Water....................................................... 4-384.2.5.3.3 Tissue...................................................... 4-39

4.2.5.4 Data / Information Gaps and Uncertainties 4-404.2.6 Nutrients.................................................................................... 4-40

4.2.6.1 Sources ..................................................................... 4-414.2.6.2 Metrics ....................................................................... 4-414.2.6.3 Temporal and Spatial Trends.................................... 4-414.2.6.4 Data Gaps / Information and Uncertainties ............... 4-42

4.2.7 Dissolved Oxygen ..................................................................... 4-434.2.7.1 Sources ..................................................................... 4-434.2.7.2 Metrics ....................................................................... 4-434.2.7.3 Temporal and Spatial Trends.................................... 4-434.2.7.4 Data / Information Gaps and Uncertainties ............... 4-44

4.2.8 Other Chemicals ....................................................................... 4-444.3 Biological Stressors................................................................................ 4-46

4.3.1 Invasive Species ....................................................................... 4-474.3.1.1 Metrics ....................................................................... 4-474.3.1.2 Temporal and Spatial Trends.................................... 4-474.3.1.3 Data Gaps / Information and Uncertainties ............... 4-48

4.3.2 Reduction of Local Stocks ........................................................ 4-484.3.2.1 Metrics ....................................................................... 4-484.3.2.2 Temporal and Spatial Trends.................................... 4-49

4.3.2.2.1 American Shad ....................................... 4-494.3.2.2.2 Sturgeon.................................................. 4-494.3.2.2.3 Atlantic Menhaden .................................. 4-494.3.2.2.4 Striped Bass............................................ 4-494.3.2.2.5 Weakfish ................................................. 4-504.3.2.2.6 Eel ........................................................... 4-504.3.2.2.7 Oyster...................................................... 4-504.3.2.2.8 Blue Crab ................................................ 4-50

4.3.2.3 Data / Information Gaps and Uncertainties ............... 4-514.3.3 Pathogens ................................................................................. 4-51

4.3.3.1 Metrics ....................................................................... 4-52

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4.3.3.2 Temporal and Spatial Trends.................................... 4-524.3.3.3 Data / Information Gaps and Uncertainties ............... 4-52

Section 5. Preliminary Ranking of Stressor Magnitude......................................5-1

5.1 Methods and Approach............................................................................ 5-15.2 Relative Ranking Stressor Magnitude...................................................... 5-2

5.2.1 Physical Stressors....................................................................... 5-25.2.2 Chemical Stressors..................................................................... 5-35.2.3 Biological Stressors..................................................................... 5-4

5.3 Key Data / Information Gaps and Uncertainties ...................................... 5-4

Section 6. Summary and Conclusions .................................................................6-1

Section 7. Literature Cited .....................................................................................7-1

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List of Tables

Table 2-1 Resources for Data and Information Search

Table 2-2 DIALOG Databases Searched

Table 2-3 Components of Electronic Bibliography

Table 2-4 DRBC Zones and Mile Conversions for the Delaware River

Table 3-1 Stressor Inventory: Sources and Types of Stressors for the Delaware Estuary

Table 4-1 Freshwater Flow of the Delaware Estuary

Table 4-2 Chronology of Major and Other Notable Floods and Droughts in Delaware, 1846–1989

Table 4-3 Delaware River Average Discharge at Trenton, 1954–1981

Table 4-4 Dredging History of the Delaware Estuary

Table 4-5 DRBC Physical Parameter Criteria for the Delaware Estuary

Table 4-6 Water Withdrawal and Consumption for the Entire Delaware River Basin

Table 4-7 Estimated Annual Sediment Budget for the Delaware Estuary, Assuming a Closed System

Table 4-8 Fish Ladder Locations in New Jersey and Delaware and Habitat Protected

Table 4-9 General Habitat Categories in the Delaware Estuary Compiled from the NLCD and ESI Maps

Table 4-10 Historical Wetland Fill at Specific Sites along the Delaware Estuary (in acres)

Table 4-11 Wetland Loss and Conversion at Specific Sites Along the Delaware Estuary

Table 4-12 Tidal Wetland Losses (Acres) and Causes by State in the Delaware Estuary

Table 4-13 Historical and Present-Day Tributaries of the Delaware Estuary Listed from South to North

Table 4-14 Overview of Causes and Sources of Impairments in Delaware Estuary

Table 4-15 PCB Mass Loading by DRBC Zone (grams per day)

Table 4-16 Toxic Substance Loadings to the Delaware Estuary, Including PCBs

Table 4-17 Mean Chlorinated Pesticides (µg/kg), PCBs (µg/kg) and Dioxins-Furans (ng/kg) in Sediment for Each Sampling Station of 1997 NOAA National Status and Trends Program – Planar PCBs in NG/KG

Table 4-18 Sample Segments for Sediment Contaminant Concentration Analysis

Table 4-19 Average Contaminant Concentrations of Chlorinated Pesticides in Sediment (µg/kg organic, dry weight)

Table 4-20 Comparison of Chlordane Analyses in Fish Conducted as Part of the New Jersey Biomonitoring Program (µg/KG wet weight)

Table 4-21 Comparison of DDx Evaluations as Part of the New Jersey Biomonitoring Program (µg/kg wet weight)

Table 4-22 Loading Estimate for the Major Point Source Dischargers to the Delaware River (RM 60–130)

Table 4-23 Metals Loading to the Delaware Estuary

Table 4-24 Estimates for Metals Loadings from Atmospheric Deposition

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Tables (con’t)

Table 4-25 Mercury Volatilization Fluxes from the Delaware Estuary

Table 4-26 Sediment Effects Level Exceedances—DRBC 1991 Study

Table 4-27 Average Contaminant Concentrations in Sediments of the Delaware Estuary—Metals (µg/g dry weight sediment)

Table 4-28 Reported Concentrations of Dissolved Trace Metals in Some East Coast Rivers

Table 4-29 Delaware Estuary Non-point Source Nutrient Loads

Table 4-30 DRBC Dissolved Oxygen Objectives for the Delaware Estuary

Table 4-31 DRBC Designated Use Impairments for Zones 2 through 6 of the Delaware Estuary Based on Dissolved Oxygen (2004)

Table 4-32 Mean Wet-Weight Concentrations (µg/kg) of PBDEs in Osprey Eggs Collected in the Delaware River and Bay Region Area

Table 4-33 Wet-Weight Concentrations (µg/kg) of Perfluorinated Compounds in Osprey Eggs Collected in the Delaware River and Bay Area

Table 4-34 List of Potential Pathways for Invasive Species Introduction

Table 4-35 Invasive Aquatic Species in the Lower Delaware Estuary (HUC = 20402)

Table 4-36 Common Invasive Plant Species Found along the Delaware Estuary

Table 4-37 Percent Composition of Cover Types Found in DNERR Wetlands

Table 4-38 List of Key Species Used in Assessment of Fishery Resources in the Delaware Estuary

Table 5-1 Rationale for Assignment of Relative Ranking of Stressor Magnitude in the Delaware Estuary

Table 5-2 Relative Ranking of Regional Stressor Magnitude by DRBC Zone

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List of Figures

Figure 1-1 The Delaware River Estuary

Figure 2-1 Ecological Zones and Tidal Wetlands

Figure 2-2 Water Quality Management Zones of the Delaware River

Figure 3-1 Federal Dredged Material Disposal Sites in the Delaware Estuary

Figure 3-2a–c Outfalls within 1 Mile of the Delaware River and its Tributaries

Figure 3-3a–c Facilities Listed on USEPA’s Toxic Release Inventory (TRI) through 2003 for the Delaware River and its Tributaries

Figure 4-1 Average Annual Streamflow at Trenton, New Jersey, for the Period 1910–1990

Figure 4-2 Total Water Use Withdrawals, 1996

Figure 4-3 Consumptive Water Use, 1996

Figure 4-4 Mean Tidal Ranges for Three Stations, 1920–1990

Figure 4-5 Projected Sea-Level Rise in the Delaware Estuary

Figure 4-6 Average Monthly Water Temperatures in the Delaware Estuary at Benjamin Franklin Bridge at Philadelphia, Pennsylvania, April to November

Figure 4-7 Salinity Distribution in the Delaware Estuary Basin

Figure 4-8 Approximate River Mile Location Range of the 7-Day Average of the 250-ppm Isochlor, 1999–2003

Figure 4-9 Delaware Estuary Water Use

Figure 4-10 Seston (mg/L) Concentrations vs. Distance above the Mouth of the Estuary for 1980–1983

Figure 4-11 Total Suspended Sediments (Seston) versus Distance down Delaware Estuary

Figure 4-12 Chlorophyll-a Biomass in the Delaware Estuary

Figure 4-13 Spatial Distribution of Sediment Types Across the Industrial Corridor of the Delaware River

Figure 4-14 Spatial Distribution of Sediment Types in the Tidal Delaware River Along the Industrial Corridor

Figure 4-15 Categories of Major Discharges to the Delaware Estuary, 1988

Figure 4-16 Sample Locations and Sampling Strata in the Delaware River Evaluated under NOAA’s 1997 National Status and Trends Program

Figure 4-17a-c Location of Sediment Sampling Stations for the Delaware River and its Tributaries Based on Regional Surveys

Figure 4-18a-c Location of Water Sampling Stations for the Delaware River and its Tributaries Based on Regional Surveys

Figure 4-19a-c Location of Tissue Sampling Stations for the Delaware River and its Tributaries Based on Regional Surveys

Figure 4-20 Documented Oil Spills in the Delaware Estuary, 1972–2004

Figure 4-21 Total PAH Concentrations in Sediments from the Delaware Estuary

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Figures (con’t)

Figure 4-22 LPAH and HPAH Concentrations in Sediments of the Delaware Estuary (dry weight)

Figure 4-23 Low Weight PAH Concentrations in Sediments of the Delaware Estuary (dry weight)

Figure 4-24 High Weight PAH Concentrations in Sediments of the Delaware Estuary (dry weight)

Figure 4-25 Volatile Organic Compounds Detected in Surface and Well Water in the Delaware River Basin

Figure 4-26 Existing penta-PCB Loadings Compared with TMDL Values

Figure 4-27 577-Day penta-PCB Loads by Source Category

Figure 4-28 Total PCB Congener Concentration in Tributary Samples during the 1996 Dry Weather Survey and 1997 Wet Weather Survey

Figure 4-29 Summed Concentrations of All Measured PCBs (excluding planar PCBs) at Stations Sampled under NOAA’s 1997 National Status and Trends Program (dry weight)

Figure 4-30 PCBs in Surface (0–3”) and Sub-surface (3–5”) Sediments Collected in the Delaware River, 1996

Figure 4-31 Profiles of Mercury, DDT, and PCBs in a Sediment Core from Woodbury Creek, New Jersey

Figure 4-32a Total PCBs in Fish and Invertebrates Sampled in the Fall (wet weight and lipid-normalized whole body, µg/kg)

Figure 4-32b Total PCBs in Fish and Invertebrates Sampled in the Spring (wet weight and lipid-normalized whole body, µg/kg)

Figure 4-33 Zonal Differences in the Fractional Contribution from Each Homologue Group for Fall and Spring Collected Channel Catfish Whole Body (normalized to total wet weight concentrations)

Figure 4-34 Zonal Differences in PCB Congener 209 Concentrations for Fall and Spring Collected Channel Catfish and White Perch (lipid-normalized)

Figure 4-35 PCB Concentrations in Fillet Samples of Channel Catfish Collected from Zones 2 through 5 of the Delaware Estuary from 1977 to 2001 (wet weight)

Figure 4-36 PCB Concentrations in Fillet Samples of White Perch Collected from Zones 2 through 6 of the Delaware Estuary from 1969 to 2002 (wet weight)

Figure 4-37 Temporal Trends in PCB Concentrations in Fish Near Trenton, New Jersey, 1969–1998 (wet weight, various fillet and whole body)

Figure 4-38 Sediment DDx Concentrations across 16 Stations (with Station 1 located at the mouth of the Delaware Estuary and Station 16 located north of Philadelphia)

Figure 4-39 Summed DDx Concentrations in Sediments Sampled during NOAA’s 1997 National Status and Trends Program (dry weight)

Figure 4-40 Chlorinated Pesticides Concentrations in Sediment at the 1997 NOAA National Status and Trends Program Stations (dry weight)

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Figures (con’t)

Figure 4-41 Regions and Sampling Locations for Biota Sampling from 1988–1991 for Pesticides and PCBs

Figure 4-42 Concentrations, by Land Use Category, of Chlorinated Pesticides and PCBs in Sediment and Fish Tissue (whole body)

Figure 4-43 Metals Loadings from Point Sources in the Delaware Estuary

Figure 4-44 Direct Atmospheric Loadings of Metals to the Delaware Estuary

Figure 4-45 Atmospheric Loadings of Metals to the Delaware Estuary via the Watershed

Figure 4-46 Summed Sediment Concentrations of Metals in the Delaware Estuary (dry weight)

Figure 4-47 Vertical Profile of Mercury in Sediment from Oldmans Creek, New Jersey (dry weight)

Figure 4-48 Range of Total Phosphorus Concentrations in the Delaware Estuary by River Mile, July–September of 1998–2003

Figure 4-49 Range of Total NH3 and NH4 Concentrations in the Delaware Estuary, July–September of 1998–2003

Figure 4-50 Distribution of Nitrite-Nitrogen in Surface Water of the Delaware Estuary from 1998–2003

Figure 4-51 Monthly-Weighted Annual Average Nutrient Concentrations in the Delaware Estuary from 1986-1988

Figure 4-52 Summer (July–September) Dissolved Oxygen Concentrations by River Mile in the Delaware Estuary, 1967–2003

Figure 4-53 Dissolved Oxygen Saturation Along the Delaware Estuary from 1990-2003

Figure 4-54 Concentrations of Total PCBs and Total PBDEs for Sediment Samples Collected in 2002 from Four Locations in the Delaware Estuary

Figure 4-55 Total PBDE Concentrations Reported for American Eel Fillets Grouped According to Collection Site

Figure 4-56 Summed Concentrations of Butyl Tin Compounds (Tetra-, Tri-, Di-, and Mono-BT) in Sediment at Delaware Estuary Sampling Stations (dry weight)

Figure 4-57 Vectors of Nonindigenous Species Transport—Delaware Estuary

Figure 4-58 Phragmites Dominated Coastal Wetlands of Delaware

Figure 4-59 Percent Comparison of the Recreational and Commercial Harvest, in Pounds, for Selected Species Landed in Delaware, 2004

Figure 4-60 Synthesized Estuary-Specific American Shad Harvest

Figure 4-61 Synthesized Estuary-Specific Sturgeon Harvest

Figure 4-62 Synthesized Estuary-Specific Atlantic Menhaden Harvest

Figure 4-63 Synthesized Estuary-Specific Striped Bass Harvest

Figure 4-64 Recreational Striped Bass Harvest, 1982–2002

Figure 4-65 Synthesized Estuary-Specific Weakfish Harvest

Figure 4-66 Synthesized Estuary-Specific Eel Harvest

Figure 4-67 New Jersey Oyster Harvest from the Delaware Estuary, 1875–2000

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Figures (con’t)

Figure 4-68 Synthesized Estuary-Specific Blue Crab Harvest

Figure 4-69 Delaware Bay Blue Crab Landings (1000s pounds) by State, 1972–2000

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Acronyms and Abbreviations

CDD chlorinated dibenzo-p-dioxinCDF chlorinated dibenzofuran CSO combined sewer overflow cy cubic yard CWA Clean Water Act DDx DDT and metabolites DELEP Delaware Estuary Program DNREC Delaware Department of Natural Resources and Environmental Control DRBC Delaware River Basin Commission DuPont E.I. duPont de Nemours and Company ERL effects range-low ERM effects range-median Estuary Delaware River Estuary ETM estuarine turbidity maximum FDA U.S. Food and Drug Administration GIS geographic information system HCB hexachlorobenzene HCH hexachlorocyclohexane HPAH high molecular weight polycyclic aromatic hydrocarbon Integral Integral Consulting Inc. LPAH low molecular weight polycyclic aromatic hydrocarbon mgd million gallons per day MS4 municipal separate storm sewer system MTBE methyl tert-butyl ether NAWQA National Water Quality Assessment (Program) NJDEP New Jersey Department of Environmental Protection NMPP National Mercury Pilot Program NJPDES New Jersey Pollutant Discharge Elimination System NOAA National Oceanic and Atmospheric Administration NOx nitrogen oxides NS&T National Status and Trends (program) OCDD octachlorinated dibenzo-p-dioxinPADEP Pennsylvania Department of Environmental Protection PAH polycyclic aromatic hydrocarbon (the) Partnership the Partnership for the Delaware Estuary PBDE polybrominated diphenyl ether PCB polychlorinated biphenyl PEC probable effects concentration pM picomolar ppb parts per billion ppm parts per million ppth parts per thousand PSEG Public Service Enterprise Group SOx sulfur oxides Study Delaware River Study SVOC semivolatile organic compound TBT tributyltin TCDD 2,3,7,8-tetrachlorodibenzo-p-dioxin TEC threshold effects concentration TMDL total maximum daily load TRI Toxics Release Inventory

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Acronyms and Abbreviations (con’t)

TSS total suspended solids USACE U.S Army Corps of Engineers USEPA U.S. Environmental Protection Agency USGS U.S. Geological Survey VOC volatile organic compound WWTP wastewater treatment plant

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Unit Conversions

ng/kg = 10-3 µg/kg = 10-6 mg/kg = ppt

µg/kg = 10-3 mg/kg = 103 ng/kg = ng/g = ppb

mg/kg = µg/g = 103 µg/kg = 106 ng/kg = 103 ng/g = ppm

ng/L = 10-3 µg/L = 10-6 mg/L = ppt

µg/L = 10-3 mg/L = 103 ng/L = ppb

mg/L = 103 µg/L = 106 ng/L = ppm

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1. Introduction

This report has been prepared by Integral Consulting Inc. (Integral) and ARCADIS BBL on behalf of E.I. duPont de Nemours and Company (DuPont), as part of an ongoing Delaware River Study that was initiated by DuPont in 2005. This work, entitled Characterization of Ecological Stressors in the Delaware Estuary is a key component of Phase I of the Delaware River Study. A companion report entitled Summary of the Historical and Current Ecology of the Delaware River Estuary (ARCADIS BBL and Integral, 2007) was also produced. The data and information presented in these reports are being used to conduct a regional risk assessment of the ecological conditions in the Estuary, and to identify and prioritize the regional data gaps for the system.

A more detailed description of the DuPont Delaware River Study is provided in the background section below. This work represents a substantial effort, conducted between November 2005 and December 2006, to provide a current review of the literature and known studies on ecological stressors of the Delaware River Estuary. The focus of this work is to compile and evaluate information on the type, magnitude and distribution of stressors that have likely influenced ecological conditions in the Delaware River Estuary historically and that are possibly influencing current conditions. This information on stressors is being integrated into an overall regional risk assessment designed to characterize, rank and determine the key stressors that are most significantly influencing the current ecological conditions in the Delaware River Estuary.

This report is structured as follows: Section 1, the Introduction, describes the Delaware River Study and how this characterization of ecological stressors fits into the study. It also defines the boundary of the study area and the key areas of focus for this report. Section 2 describes the approach and methods used to conduct this characterization. Section 3 provides an overview of the types of ecological stressors and the categories of associated sources. Section 4 contains a discussion of regional stressors, including physical, chemical, and biological stressors. Section 5 presents a preliminary ranking of the magnitude of regional stressors. Section 6 is the summary and conclusions for this report. A list of the literature cited in this report is provided in Section 7.

1.1 Background

The Delaware River Estuary (hereinafter referred to as the “Delaware Estuary” or “Estuary”) has been influenced and impacted (i.e., modified) by human activities for more than four centuries. The changes that have occurred in the Estuary during this time are wide-ranging and substantial. Most notable are the impacts that have occurred in the middle to upper portion of the Estuary where, since the early 19th century, the River corridor and its adjacent habitats have been altered and degraded, (i.e., adversely impacted from an ecological perspective) by urbanization and industrialization with associated pollution problems and changes in water quality and ecological communities. Today, the Delaware River remains the largest un-dammed river in the United States, and its Estuary is home to four large cities (Wilmington, Delaware [DE]; Philadelphia, Pennsylvania [PA]; Camden, New Jersey [NJ]; and Trenton, NJ), as well as many smaller urban and industrial corridors. The Estuary also contains the largest freshwater port of commerce in the United States (fifth largest port complex overall). This complex includes the ports of Trenton, Philadelphia, Camden, Wilmington and Salem. These are referred to as the Ports of the Delaware Estuary, or sometimes the Ports of Philadelphia.

In urbanized systems such as the Delaware Estuary, it is important to understand and, to the extent possible, quantify the relative contribution of the various stressor-related impacts, both historical and ongoing, to the condition of the ecosystem as a whole. Only then can the

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incremental impacts from any given stressor to the system be understood. Moreover, by understanding the history of the system and the cause-effect relationships that have changed its ecology and human uses over time, it may be possible to define and prioritize a “scope for restoration” (i.e., the level of impairment for various natural resources in the system) and evaluate the cost-benefit of a range of potential restoration options, both at a regional and local level.

In January and May 2005, the Partnership for the Delaware Estuary (“the Partnership”) convened a two-part Delaware Estuary Science and Management Conference to bring scientists, resource managers and other interested parties together to discuss and summarize the current state of the science and to identify and prioritize key science and management needs for the Estuary. This was the first such conference of its kind since the publication of the Comprehensive Conservation and Management Plan (CCMP) by the Delaware Estuary Program (DELEP) in 1996. In January 2006, the Partnership published a report titled White Paper on the Status and Needs of Science in the Delaware Estuary (herein referred to as the Partnership’s White Paper [Kreeger et al., 2006]).

The Partnership’s White Paper identified the top ten technical needs (i.e., categories of scientific data and information) that were prioritized at the Delaware Estuary Science and Management Conference and the top six operational needs related to organizational programs and actions related to management of the resource. It also emphasized the need for better linkage in the future between science and management actions. In its “blueprint for addressing scientific needs”, the Partnership’s White Paper indicated that there are multiple stakeholders and agendas at work in the Estuary and that there has been little coordination amongst them to date. Of particular note are the considerable industry and port interests that operate in the Estuary and the fact that few of these are broadly engaged in the scientific and technical community. The recommendations of the Partnership and other participants in the conference were to engage as many stakeholders as possible in the process and attempt to move on the road to a common sharing of scientific data and information in the hope that this will help foster communication and cooperation toward restoring and managing the Estuary in the future. To that end, a second Delaware Estuary Science and Management Conference was recently held in January of 2007. In addition, the CCMP is being revised and updated to reflect the current scientific and management priorities of stakeholders in the system.

In the summer of 2005, DuPont initiated Phase I of its Delaware River Study. This study is being implemented with the following goals:

1. To broadly synthesize and summarize the readily available data and information on historical and current stressors to the Estuary;

2. To conduct an evaluation of the ecological condition of the Estuary and to compare the conditions on a regional basis within the Estuary;

3. To determine key regional data gaps and means to fill these data gaps for evaluating multi-stressor impacts to the Estuary; and,

4. To evaluate the potential contribution from the three DuPont facilities on the shores of the Estuary (Chambers Works and Repauno in NJ, and Edgemoor in DE) to the overall regional conditions of the Estuary watershed.

The results of Phase I will be used to develop the scope of work for Phase II of the Delaware River Study. Although the Delaware River Study did not evolve from the Delaware Estuary

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Science and Management Conference or the Partnership’s White Paper, it will provide important information and analyses that should augment ongoing work by the Partnership and others within the watershed of the Estuary. Collectively, these programs will greatly enhance our understanding of ecological conditions within the Estuary and allow for informed decision-making regarding potential restoration opportunities.

1.2 Objectives of Report

The primary objective of this ecological stressors characterization for the Delaware Estuary is to help synthesize the data and information that is necessary to conduct a multi-stressor risk assessment of the system. The data and information contained in this report will be used to build a regional conceptual model that defines the interlinking between stressors and ecological receptors within the Estuary and to evaluate which stressor–receptor relationships are most significantly influencing the current regional ecological conditions of the system. Ultimately, this effort in concert with the other efforts undertaken in the Delaware River Study, will aid in determining important restoration needs and will help to further define the lost/impaired ecosystem functions in the watershed.

With that in mind, the focus of this report is to compile and summarize the large body of available data and information that exists for regional stressors in the Estuary. Our goals were to:

� Compile and evaluate as many of the readily available reports, publications and databases for the Estuary as possible within the timeframe of this Phase I investigation;

� Create a searchable electronic bibliography of these resources;

� Identify the key physical, chemical and biological stressors that occur regionally in the Estuary;

� Characterize the magnitude of these stressors and how they vary in space and time; and,

� Provide perspective on potential uncertainties associated with understanding these stressors.

There is a large body of knowledge and information that exists for the Estuary (both current and historical) including a number of summary reports and bibliographies that have been created. Our synthesis builds from, extends, and updates these available summary reports and bibliographies as described in A Summary of the Historical and Current Ecology of the Delaware River Estuary (ARCADIS BBL and Integral, 2007).

We focused on syntheses of readily available literature rather than on conducting new evaluations of raw data. Regional data sets that will support the regional review of ecological conditions (to be prepared subsequently) were considered to be of the greatest importance for this work. We understand that there are significant site-specific data sets that have been developed to satisfy operational and regulatory requirements at individual facilities throughout the Estuary. This facility-specific level of data collection and synthesis was beyond the needs and scope of our effort, which has been directed towards understanding regional stressors in the Estuary.

As a key part of the overall Delaware River Study, we have developed a bibliographic “clearinghouse” for reports, publications, maps, databases, etc., that were obtained under this Phase I study and developed a searchable electronic bibliography of the materials collected to

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date. This bibliography was created in Microsoft® Access. Many of these resources have also been scanned and created in an electronic (i.e., pdf file) format. The objective of the electronic bibliography and files is to make information review and transfer for the Estuary a more simple process. We anticipate this process to continue in Phase II of the Delaware River Study. A more detailed description of the bibliography is provided in Section 2. The electronic database and a printout of all information from the database were previously provided in ARCADIS BBL and Integral (2007).

1.3 Study Area

The study area for Phase I of the Delaware River Study is the Delaware River from head of tide at Trenton, NJ, downstream to its confluence with the Atlantic Ocean at Cape Henlopen, DE (Figure 1-1). This area encompasses both the Delaware Bay, (River Miles 0–54), and the middle brackish (River Miles 54–80) and upper freshwater portions of the Estuary (River Miles 80–133). This boundary captures a unique portion of the River ecologically (i.e., the tidal Estuary) and also includes the major industrialized portion of the River and its four largest cities—Wilmington, DE; Philadelphia, PA; and Camden and Trenton, NJ. While an extensive freshwater ecosystem and watershed are present above the Estuary, and these areas significantly linked to the overall ecological conditions in the Estuary (e.g., through water withdrawals, supplies of nutrients and solids, spawning habitat for migratory species, etc.), the area of this investigation was limited to the estuarine portion of the River due to its unique ecological setting and conditions, industrialized character and utilization as a major port complex.

Existing data and information that were readily available in the public domain were initially compiled and evaluated for the entire Estuary. The objective of this broad characterization was to conduct an initial data examination on the types and likely magnitude of ecological stressors to the system and then to focus the remainder of our characterization on those parts of the Estuary that have historically been or continue to be impacted by a wide range of physical, chemical, and/or biological stressors.

Our literature search and data collection were directed at information on the main-stem of the Estuary itself and the shoreline areas immediately adjacent to the River. We did not focus our search or characterization on tributaries to the Delaware River in the Phase I study. However, some key information related to tributaries is presented in this report as appropriate.

From our initial examination of existing reports and publications, it is clear that the Estuary, from an impacts standpoint, can be divided into the more urbanized/industrialized section above the Delaware Bay and the less industrialized/impacted Bay itself. While the Delaware Bay has been changed over time by human influences and continues to be impacted ecologically from a variety of factors, it has not been subject to the substantial levels of industrialization and influences from the major metropolitan areas in a similar fashion to the upper portions of the Estuary (i.e., above the Bay). It is the upper reaches of the Estuary above the Bay that are subject to considerable ongoing impacts from industrialization/urbanization, and are the focus of most of the present regulatory initiatives in the Estuary (Kreeger et al., 2006; DRBC, 2004). For these reasons, we focused our more detailed data and information searches and characterization on the Estuary primarily above the Delaware Bay.

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2. Approach and Methods

This section describes the approach and methods that were used to collect, compile and evaluate the readily available environmental data and information for the Delaware Estuary that supports all tasks under the Delaware River Study. The result of these efforts was the production of: 1) a working electronic bibliography of obtainable resources (publications, maps/charts, and Internet/database resources), 2) an earlier report titled A Summary of the Historical and Current Ecology of the Delaware River Estuary (ARCADIS BBL and Integral, 2007), and 3) this report, which characterizes the physical, chemical, and biological stressors that occur regionally in the Estuary. Collectively, this information will be used to support the upcoming regional assessment of ecological conditions in the Estuary.

2.1 Data and Information Search and Compilation

A step-wise process was used in our data and information search in order to characterize the spatially and temporally large and diverse data sets and information sources in an effective manner. As a first step in the process, readily obtainable data and information were gathered, prioritized, and preliminarily reviewed. These materials included books and summary reports on the environmental resources and history of the Estuary and information that could be downloaded from the Internet. This first set of data/information was then examined and used to: 1) identify the key natural resource categories, human use factors, and spatial impact issues for the Estuary, and, 2) determine the need for additional, more focused searches and data and information acquisitions. The key objective of this first step was to focus the remainder of the investigation on those resources and areas of the Estuary that are most important relative to evaluating multi-stressor impacts. Additionally, as a result of this initial review, subsequent data collection efforts were focused geographically on the portion of the Estuary that is upstream of the Delaware Bay for reasons described in Section 1.3 (“Study Area”).

The second step of the process was to conduct a more detailed data and information search and compilation. Existing bibliographies and databases, including the bibliography of Sutton et al. (1996), were used to the extent possible for this task to maximize technical effectiveness. Other key sources for this search included the Delaware River Basin Commission (DRBC) library and the Partnership’s publications Internet page, the existing DuPont geographic information system (GIS) database, government/stakeholder/university libraries and Internet sites, and local/regional historical societies. In addition to reports, a large number of databases housing chemical and biological analytical results and geographic information were reviewed. Examples of these databases include the National Oceanic and Atmospheric Administration’s (NOAA) National Status and Trends (NS&T) Program Database, the U.S. Fish and Wildlife Service’s (USFWS) National Wetland Inventory, and the U.S. Environmental Protection Agency’s (USEPA) STORET database, the Toxics Release Inventory (TRI), and Enviromapper. A comprehensive listing of the specific resources searched in our efforts relevant to regional stressors is provided in Table 2-1.

Included in Table 2-1 is Dialog (www.dialog.com), an information service accessed via the Internet that can retrieve literature citations contained in more than 900 databases. The search of this source was restricted to 71 databases that contain environmental literature. Table 2-2 lists the databases that were accessed as part of this search. The search conditions combined “Delaware River” and “Delaware Estuary” with the following terms: ecology, environmental, historical, wetlands, habitat, wildlife, toxicology, bioaccumulation, surface water, sediment, hydrodynamics, hydrogeology, and dredging. This search returned an extensive list of article and report titles.

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The list was reviewed to determine which titles might be relevant to the objectives of this investigation and as many of these articles and reports as possible were obtained through library visits, online acquisitions, and interlibrary loans.

In addition to Internet-based searches and library visits, a number of telephone and/or e-mail contacts were made with regulatory agencies (see Table 2-1). These efforts focused on individuals, sections, and divisions known to be involved in the Estuary and thought to have knowledge of, or access to, data and information that might otherwise be unavailable.

The data and information that were collected were synthesized into a succinct accounting of the various categories of impacts that have affected the environment of the Estuary since the European colonization of the region. Data and information were targeted from the following broad categories:

� Human settlement and population expansion;

� Waterway characteristics (dredging, canals, bridges, piers, wharfs, dams, etc.);

� Urbanization and industrialization;

� Hydrodynamics;

� Shorelines and wetlands;

� Plankton communities;

� Benthic invertebrate communities;

� Fish and shellfish;

� Wildlife (birds, mammals, reptiles, amphibians);

� Water quality, contamination, and toxicity;

� Sediment quality, contamination, and toxicity;

� Bioaccumulation and pathology;

� Commercial shipping;

� Recreational and commercial fishing; and,

� Other recreational uses (swimming, boating, rowing, hunting, etc.).

These categories represent the types of information that are necessary to identify regional stressors to the system (historical and current), as well as the changes in ecological and human use of the Estuary over time. In addition, they provide information that can be used to meet the long-term goal of evaluating potential mitigation/restoration options for the Estuary.

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The final step in the process was reviewing the existing reports and their respective bibliographies and targeting a number of additional key publications, maps, and Internet sites for a final set of data/information gathering. This iterative approach to our data/information compilation and review allowed the process to remain focused and identify the important data and information that are necessary to complete each of the Delaware River Study tasks: summarization of historical and current ecology of the Estuary, multi-stressor assessment, ecological conditions characterization, and identification of data gaps.

2.2 Bibliography Development

An electronic bibliography was developed to catalog and summarize the data and information obtained from our searches. The bibliography was developed as a database in Microsoft® Access Version XP. Select references that were extracted from the bibliography and cited in this report are provided in Section 7 (Literature Cited).

The objective of the bibliography task was to create a “clearinghouse” of readily available/obtainable reports, maps, databases, and Internet sites for the Estuary in an electronic, searchable, and easy-to-update format. Our goal was to provide not only a citation for the references that were collected, but also to include a brief, high-level overview of the categories of data and information that are contained in each of the references in the bibliography. In this way, the reader can either search the bibliography for references that contain specific types of data/information (e.g., fish populations, wetlands, water quality, or sediment toxicity data), or scan its contents and see the various types of information that are included in each reference. Table 2-3 contains a summary of the components of the bibliography and the information categories that it contains.

This bibliography presents the most up-to-date set of references on environmental resources of the Delaware Estuary and, as a searchable database, provides an effective means to determine readily available references for specific types of data and information about the Estuary. The creation and maintenance of a bibliographic database like this is a positive step towards synthesizing and making available to all scientists, resource managers, and other interested parties an up-to-date account of the historical and existing research on the Estuary.

Although the electronic bibliography is fairly comprehensive, it is by no means a complete accounting of all resources and references for historical and current studies in the Estuary. In addition, the bibliography includes only those references or resources for which we were able to obtain copies to review. The result is a set of approximately 500 references collected to date, many of which are available in electronic (i.e., .pdf file) format. As such, the bibliography contains a robust set of references and, because of its structure as a database, can be easily updated with additional references in the future. The electronic database and a printout of all information from the database were previously provided in ARCADIS BBL and Integral (2007).

2.3 Delaware Estuary Zones of Study

In characterizing the 133-mile long Estuary, it is most practical to segment the presentation of data and information by zones. There are two existing types of zones that have been defined and are widely used for the Estuary.

First, there are three primary ecological zones in the Delaware River Estuary (Figure 2-1), as defined mainly by differences in salinity (Kreeger et al., 2006). The upper zone is the freshwater tidal zone, which extends from the head of tide at Trenton, NJ, to Marcus Hook, PA (River Miles 80–133). The transition zone, which extends from about Marcus Hook to Artificial Island, NJ

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(River Miles 54–80) has a wide salinity range (about 0–15 parts per thousand [ppth]), depending on the tide and freshwater flows in the River. The lower zone is the Delaware Bay, which is a large open embayment (River Miles 0–54) with saline waters that extends to the Atlantic Ocean.

Second, the DRBC has defined six water quality management zones in the Delaware River (Figure 2-2; Table 2-4), five of which (Zones 2 through 6) comprise the Estuary. Zone 1 is the non-tidal Delaware River from its headwaters to Trenton, NJ, which is outside of the Estuary boundaries. These six zones were primarily defined for regulatory management purposes in contrast to the ecological zonation described above. However, the DRBC zones are widely utilized in many publications for summarization or reporting of data and information.

In this report, we discuss data either by the type of zone in which it is reported by the primary authors, or that which makes most sense for the particular resources under discussion in each section. In some instances, data for more specific areas of the Estuary are presented.

2.4 Data Review and Presentation

In the following sections, we provide an overview of regional stressors and their potential regional sources. As stated previously, it is not our intention in this report to re-create the detailed characterizations of the stressors in the Estuary that have been provided by others, nor to independently synthesize and analyze the substantial amount of monitoring data that has been collected over the decades. Instead, we have attempted to build on existing characterizations and update them with additional data and information that are relevant to the multi-stressor and regional risk characterizations that are being performed in Phase I of the Delaware River Study.

We focused on regional data sets when available to provide an overview of stressors throughout the Estuary. Studies that provide data for localized areas have been used in the absence of regional data or when they provide important site-specific examples of stressor occurrence. The regional focus on stressors will support the regional risk characterization that is also being completed as the next step of the Delaware River Study. In many instances, we have excerpted brief summaries of what was contained in the previous characterization reports and built on them with more recent data from the past decade. In addition, tables and figures that show trends over time are presented, many of which have been directly obtained from the literature. In other instances, we have conducted our own interpretation of maps and data to draw conclusions about impacts to resources that were not addressed in detail in previous reports.

In certain instances, we supplemented our data synthesis and analysis by generating GIS maps. Through Internet searches, we obtained state-wide information on a number of stressors such as point source discharges and locations of facilities with reported releases of hazardous materials. Our GIS maps help us to understand the spatial distribution of stressors throughout the region. In each of our maps, we note the data source and how this information was characterized by the originating organization.

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3. Sources and Types of Stressors in the Delaware Estuary

This section provides an overview of the types of regional stressors present in the Delaware Estuary, and identifies the primary sources of these stressors. We utilize general concepts for stressor characterization outlined in the ecological risk assessment guidance developed by USEPA (1998a) as well as elements of the general framework for stressor identification developed by USEPA (2000) to develop an inventory of stressors that are potentially important in defining the current ecological condition of the Estuary. Key steps in the process under both of these approaches are to develop an initial list of stressors and to critically review the available information for those stressors to characterize their magnitude and their distribution across space and time.

Though stressor identification can be conducted for any level of biological organization, we focus on identifying stressors that have sufficiently large scales such that they could affect the ecological communities of the Estuary as a whole. This information will be used subsequently to help develop a conceptual model for the Estuary and to conduct the multi-stressor regional risk assessment. Detailed information on the characteristics, magnitude, and distribution of regional stressors is provided in Sections 4 and 5.

3.1 Stressor Definition, Categories, and Interactions

Stressors are defined as the physical, chemical, or biological factors that induce adverse biological responses in an ecological system (USEPA, 2000). In any given location, it is the interaction of stressors and the biological responses to them that in part influence the composition of ecosystems and the biological communities within them. Resident species present in a local community are usually those that are best adapted to the local environment and the mixture and magnitude of physical, chemical, and biological stresses placed upon them. Stressors have the ability to illicit or enhance adverse changes in the structure, function, and inherent health of resident communities.

Stressors may be natural or anthropogenic in origin. Non-anthropogenic stressors are natural components of ecological systems that become stressors only when they are present at suboptimal levels. Such stressors include salinity, dissolved oxygen, and the presence of inorganic and organic compounds, such as metals and nutrients. For example, salinity is a natural variable that changes over time and space throughout the Estuary. It can become a stressor because plant and animal species are adapted to specific salinity ranges and are adversely affected when conditions are outside of those ranges. For example, historical changes in wetland vegetative communities throughout the Estuary have been directly correlated with changes in salinity (ARCADIS BBL and Integral, 2007). Anthropogenic stressors also play a substantial role in the historical and current ecology of the Estuary (ARCADIS BBL and Integral, 2007).

Across both natural and anthropogenic sources, important stressors in the Estuary can be grouped into one of the following categories:

� Physical stressors. Physical stressors are those that alter the physical environment. Physical stressors in the Estuary include habitat alteration, temperature, salinity, suspended solids, sedimentation, water volume, and physical barriers that prevent fish access to tributaries and streams.

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� Chemical stressors. Chemical stressors are defined as toxic chemicals and nutrients present in various media as well as dissolved oxygen in water. When present at certain concentrations, chemical stressors can impair the growth, reproduction, or survival of exposed organisms. Reduction or elimination of species due to chemical stressors can result in shifts in the structure, function, and the inherent health of resident communities.

� Biological stressors. Biological stressors are changes to the character and composition of natural communities that occur outside of natural ecological succession processes. Biological stressors include the introduction of non-native species that may out compete or displace native species (i.e., become invasive), thereby potentially altering habitat and the food web. Other biological stressors include reductions of local fish or shellfish stocks due to over harvesting, potentially resulting in concomitant reductions in the food supply for predators or, in the case of clams and oysters, concomitant changes in habitat characteristics that influence benthic dwelling species. Pathogens are a third type of biological stressor that occurs in the Estuary.

The degree to which an ecological community is impaired by any given stressor depends upon the magnitude of the stressor, its interaction with other stressors, the tolerance/sensitivity of the member species (i.e., stressor-response profile), and their interactions with each other. In industrialized waterways such as the Estuary, stressors seldom occur in isolation. Therefore, potential interactions of stressors are especially important in characterizing overall responses. Interactions of stressors can compound or magnify community responses. For example, benthic community composition can undergo a shift in response to a host of stressors. Among these would be physical stressors that include movement of the salt wedge farther up the Estuary as a result of substantial dredging, withdrawal of freshwater, and sea level rise. Community shifts could be additionally affected by chemical stressors released to the environment, either from dredging or from ongoing or historical sources. Stressor distribution throughout the Estuary is also heterogeneous, with the magnitude and presence of stressors representing a changing patchwork over space and time. A high potential for ecological impairment exists when multiple stressors co-occur at their highest magnitudes.

Given these many complexities of stressors and ecological communities, detailed technical studies are often required to elucidate cause-and-effect linkages between stressors and responses and to identify those stressors that are predominantly responsible for observed ecological changes. It is difficult to conclusively identify which stressor is responsible for each kind of observed biological impairment. Instead, a list of candidate causes of impairment is typically compiled and ordered, followed by an identification of the kinds of additional evaluations that would be needed to more precisely identify leading stressors (USEPA, 2000). However, in many cases, impairment is due to the combined effects of multiple stressors, such that the isolation of single causes is not plausible. Consequently, the simple identification of a potential stressor may not lead to a conclusive rationale for causation, and additional information is usually required to determine whether a causative relationship can be established between a stressor or group of stressors and a biological response.

In any event, a detailed understanding of the types, sources, and magnitude of the stressors, how they exist and co-exist across space and time, and how the ecological community responds to them is necessary to support any type of stressor-response analysis. This information, therefore, is a necessary precursor to subsequent planning efforts to characterize further the key stressors in the Estuary and to design strategies to manage or mitigate any specific contributions to their overall effects.

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3.2 Stressor Sources

The origin of a stressor is termed its source (USEPA, 2000). Stressor sources are generally linked to actions that physically alter habitats, release chemicals, or directly alter the species composition of the community. The range of sources of physical and chemical stressors to ecological communities are typically more abundant than sources of biological stressors, although the impact from biological stressors can be as or more significant.

The collective data and information compiled for this investigation indicate that there are a variety of potential sources that could be contributing stressors to the Estuary. Potential sources are presented below, along with accompanying background information on how they contribute stressors.

3.2.1 Dredging and Channelization

Dredging involves removal of sediments from a water body, typically using a bucket or hydraulic dredge. Dredging has occurred in the Estuary since the early 1800s and is necessary to create or maintain shipping channels and to provide nearshore berthing areas for loading and unloading. The current primary shipping channel in the Estuary has a federally authorized depth of 40 ft. When maintenance dredging occurs, dredge depths are usually in excess of 2 ft., and frequently exceed 4 ft. below the target depth (i.e., the mud line).

Dredging is a source of a number of stressors. When sediments are dredged, the resident benthic community is disturbed or removed. Benthic organisms will rapidly re–colonize the newly exposed sediment surface, but it may take months to years for the original community structure to become reestablished. In addition to altering benthic community structure, dredging creates new and deeper channels, which facilitate saltwater intrusion in upriver areas and increased tidal range (Najarian Associates, Inc., 1993). Dredging may also affect local sedimentation patterns and hydrodynamics, and can lead to the loss of riparian marshes due to removal of suspended sediment sources that would otherwise accrete along the shoreline (Sharp, personal communication). Short-term impacts associated with dredging typically include increased turbidity and decreased dissolved oxygen in the immediate vicinity of the dredging operation. Redistribution of sediment-bound contaminants can occur when contaminated sediments are dredged. Lastly, fish may be entrained, especially with hydraulic dredging.

3.2.2 Dredged Material Disposal

Material that is removed from the Estuary must be deposited somewhere, and currently, disposal of dredged material typically occurs at designated open-water disposal sites or in upland areas. Thousands of acres of wetlands and stream banks were filled in the Estuary during the 19th and 20th centuries for the purposes of dredged material placement (Snyder and Guss, 1974), resulting in significant habitat loss and alteration. Figure 3-1 depicts areas of federal dredged material placement along the Estuary. In addition, historically dredged materials could contain contaminants that are now acting as a source of chemical inputs to the Estuary. Today, federal and state regulations require testing of sediments that will be dredged to guide the decision of where the dredged material can be disposed (USEPA and USACE, 1998).

3.2.3 Maritime Operations

Maritime operations is a term used to broadly encompass the variety of activities associated with the operation of the commercial shipping industry, including vessel traffic and port facilities, as well as the operation of marinas. The Estuary is the largest freshwater port of commerce in the U.S. and maritime operations in the region are thus extensive. Maritime operations also are the source of a number of stressors to the Estuary. Construction of port and marina facilities results

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in habitat loss in the uplands and/or nearshore areas and can lead to increases in local surface water runoff. Increased vessel traffic can lead to shoreline erosion from wave action and local spikes in turbidity from propeller wash (DELEP, 1996). Maritime operations can also result in the disturbance of foraging and nesting wildlife, such as certain predatory birds and shorebirds. Maritime operations are also associated with petroleum-related releases from commercial vessels both into the water, as well as diesel exhaust into the air. Spills of liquid and solid products that are being transferred between cargo ships and the uplands occasionally occur at active port terminals. Chemicals associated with anti-fouling paints previously used primarily on commercial vessels (e.g., tributyltin, or TBT) are well documented as causing adverse impacts to some invertebrate species. Release of bilge waters from large vessels has also been implicated in the introduction of certain invasive species.

3.2.4 Recreational Boating

Recreational boating is a common activity in the Estuary. The primary stressors associated with recreational boating are the release of petroleum products and the disturbance of certain wildlife. Recreational boating also can be the source of invasive species (primarily plants).

3.2.5 Commercial and Recreational Fishing

Commercial and recreational fishing occur throughout the Estuary, and focus on a number of target species. The operation of commercial and recreational vessels for fishing and shellfish harvesting can lead to releases of petroleum-related compounds into the water and air. Over-fishing also can result in the reduction or complete extirpation of local fish and shellfish stocks (see Section 4.3.2 for information on individual stocks), which can in turn affect other species that rely on those stocks for either food or habitat. Fishing and harvesting gear, such as trawls and oyster tongs, can impact bottom habitats while the use of gill nets is associated with the incidental catch of non-target species (i.e., “by catch”).

3.2.6 Dams and Weirs

Dams and weirs are constructed to manage water flows, prevent flooding, and sometimes to generate electricity. The Delaware River is the “last major free-flowing river east of the Mississippi” (Albert, 1987). Currently, there are no dams on the main-stem of the Delaware River including within the Estuary. However, dams and weirs (which permit flow once the water exceeds a certain level) have been constructed on many of the River’s tributaries. These structures can alter the natural geomorphology of a tributary from sediment accumulation caused by decreased flow velocity. Additionally, these structures can prevent the passage of fish, cause flooding in low-lying land, and promote sedimentation behind the structures. For those species that rely on the tributaries and associated creeks for spawning (e.g., American shad), or use these areas as habitats after marine spawning (e.g., eels), construction of dams or weirs without fish ladders effectively eliminates the habitat above these structures. Removal of dams and weirs, and construction of fish ladders, has successfully allowed fish to become reestablished in tributaries where they once thrived. Notably, in 1996, the Public Service Enterprise Group (PSEG) constructed 13 ladders to increase river herring access to historical spawning areas previously closed off by dams (PSEG, 2004). Dam removal, however, can result in an increase in physio-chemical stressors due to the sudden release of accumulated sediments, potentially containing chemical contaminants.

3.2.7 Urban Development

The watershed surrounding the Estuary has been subject to urbanization for centuries. Many environmental impacts are associated with urban development, though the type or character of these impacts varies over time. On a very basic level, urbanization in the Estuary watershed has

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led to loss of upland, nearshore and aquatic habitats. For example, 30% of streams that could be seen entering the Estuary on maps created between 1886 and 1927 have either completely disappeared (based on present day maps) or no longer appear to enter the Delaware River due to filling, damming, redirecting, or rerouting underground (ARCADIS BBL and Integral, 2007). In habitats that do remain, they are often subject to a variety of stressors that stem from urbanization. Historically, this could have included increased runoff and loading of sediments and pollutants into the Estuary. In more modern times, the presence of impervious surfaces (e.g., roads, parking lots, airport runways, and structures) reduces groundwater recharge and increases the volume of piped storm water discharged via storm-drain outfalls, which can in turn result in increased turbidity in the receiving waters, and localized sedimentation near outfalls. Contaminants associated with runoff from urbanized areas commonly enter receiving waters. Industrial activities and exhaust from vehicular traffic may contribute to degraded air quality and atmospheric deposition of contaminants that are transported to the Estuary via storm water or gaseous exchange.

3.2.8 Agricultural Land Use

The Delaware Bay is surrounded by a large network of agricultural land. The transition of forests to agricultural lands located at some distance from the Estuary can affect water quality and sediment quality in the Estuary. Fertilizers, pesticides, and herbicides used in agricultural operations can be transported via groundwater and/or surface water to the Estuary and subsequently affect resident species. In addition, soil runoff from agricultural areas can lead to increased sediment loading to the Estuary, with subsequent increased turbidity and sediment deposition. Loadings of excess nutrients are additionally associated with a number of agricultural activities.

3.2.9 Shoreline Alteration

Most of the shoreline area along the upper Estuary has been developed for industrial or commercial use and has minimal habitat value. The construction of waterfront structures, piers or wharfs, shoreline roads, and bridges all can affect the nearshore physical environment of a water body. Shorelines may be filled and then stabilized by riprap or other materials to prevent erosion in front of or beneath shoreline structures. Filling and stabilization reduces shallow-water habitat. Bridges with in-water supports alter localized hydrodynamics, often leading to scouring next to and behind the structures and subsequent accretions in downstream areas.

3.2.10 Drought and Water Withdrawal

Reduced water levels in estuaries due to drought or water withdrawal for municipal or industrial uses can alter system hydrodynamics, expose more shoreline, and allow the salt wedge to move farther up an estuary. These changes in physical habitat may negatively impact certain species, while allowing more tolerant or opportunistic species to occupy areas they were previously unable to inhabit. Drought-stress also can render the natural community more susceptible to other stressors, such as endemic disease. For example, a decline in the Estuary oyster population coincided with an outbreak of the parasite-transmitted Dermo disease in oysters during a significant drought in the mid-1980s.

3.2.11 Municipal Wastewater Discharges

The discharge of municipal wastewater to the Estuary was historically a greater stressor than it is today due to implementation of the Clean Water Act (CWA) in the 1970s. Prior to treatment, significant organic loads were associated with wastewater outfalls, and industrial connections to municipal sewer systems could add significant amounts of chemical contaminants. Under the CWA, municipalities have installed advanced treatment systems and require permits for the

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discharge of industrial wastes to their collection systems. Today, hydrophobic contaminants that enter a wastewater treatment plant (WWTP) are largely captured in the biosolids fraction. By contrast, the dissolved fractions of chemicals, if not subject to additional treatment, can be discharged as part of the effluent. Chemicals that are used as disinfectants in the water supply system, such as chlorine and bromine, are also discharged through WWTP outfalls. Though to an unknown extent, pharmaceuticals and personal care products (PPCPs) from residences and facilities (including hospitals) can also pass through WWTPs relatively untreated and enter the Estuary.

3.2.12 Combined Sewer Overflows

Combined sewer overflows (CSOs) are emergency overflows that allow untreated or partially treated sewage to be discharged to receiving waters. Releases from CSOs occur when a WWTP exceeds its capacity (typically during periods of excessive precipitation), or when pumping stations fail. Because raw sewage has not undergone treatment, chemical concentrations in CSOs are higher than in WWTP effluents. Pathogens may also be found in CSO releases. Historically, CSO releases could contain significant contaminant loads. Also, the frequency with which CSOs discharged was generally higher in the past because storm water was often piped with sewage. Though to an unknown extent, PPCPs can also be introduced to the Estuary via CSO releases. Over the past decade or so, many municipalities, including Philadelphia, have been separating their storm water and CSO lines and creating greater water storage capacity, thereby reducing the frequency of CSO releases (Dahne and Smullen, 2000).

3.2.13 Stormwater

Stormwater transports eroded soils, spilled and leaked materials, and materials deposited from the atmosphere. Stormwater carries a variety of contaminants, depending on the nature of the drainage basin. In urban areas, storm water typically contains a full range of semi- and nonvolatile chemicals (e.g., petroleum-related chemicals from road surfaces and parking areas). Concentrations tend to be low due to dilution; however, when storm drain outfalls discharge to quiescent water bodies (e.g., embayments, slips) the accumulated sediment that was discharged from the storm drain may not be diluted by other sources of sediment and can therefore contain significantly elevated chemical concentrations.

Locations of permitted outfalls, which can include WWTPs, CSOs, storm drains, and industry, are mapped in Figures 3-2a–c and are based on information gathered from the state agencies of NJ, PA, and DE (i.e., New Jersey Department of Environmental Protection [NJDEP], Pennsylvania Department of Environmental Protection [PADEP], Delaware Department of Natural Resources and Environmental Control [DNREC]). Each state differs somewhat in the type of information that it makes publicly available. For example, PA does not release detailed information on specific WWTP outfalls for security reasons. Despite such differences, the data in Figures 3-2a–c are illustrative of the number of permitted outfalls that discharge to the River and its tributaries (e.g., Rancocas Creek, the Schuylkill River, Oldmans Creek, and the Christina River). Approximately 860 outfalls are present. These include approximately 170 in DRBC Zone 2, 190 in DRBC Zone 3 (inclusive of the Schuylkill River), 320 in DRBC Zone 4 (inclusive of the Schuylkill River), and 180 in DRBC Zone 5.

3.2.14 Electric Generating Facilities

Electric generating facilities are usually constructed along rivers and estuaries because they often require a readily available supply of cooling water. The Estuary is no exception and there are 15 electric generating facilities operating on the shorelines, including two nuclear power facilities in the Delaware Bay (Salem and Hope Creek facilities) (USEPA, 2006b). As with other industrial

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facilities, construction of electric generating facilities can impact a substantial amount of upland and nearshore areas, with the concurrent loss of natural habitat. Some electric generating facilities typically withdraw large volumes of water for cooling purposes, which may alter local hydrodynamics and can lead to entrainment and impingement of fish and other aquatic life (USEPA, 2002). (Impingement is when an aquatic organism is trapped (stuck) on the screen of a cooling intake, leading to death via starvation, asphyxiation, descaling, or exhaustion. Entrainment is a stressor for small fish and larvae, and other small organisms by which entire organisms pass through cooling intake systems, with varying degree of mortality influenced by developmental stage.) Facilities often discharge that water back into rivers and estuaries at permitted, albeit elevated, temperatures. Outfall diffusers and mixing zones are often required under federal and state permits for the discharge of cooling water to minimize environmental impacts. Certain chemical groups have been associated with electric generating facilities, including metals, petroleum-related compounds, and nitrogen- and sulfur-containing compounds. Biocides, such as chlorine and bromine, may be discharged as well.

3.2.15 Industrial Facilities

Industry has been present on the Delaware River since the 18th century. Industrial facilities were constructed along the banks of the Estuary to facilitate the transport of raw and finished products and to provide the large quantities of water that were typically needed for their operations. Currently, there are a substantial number of waterfront industrial facilities along the Estuary, including 17 petroleum bulk terminals and general petroleum facilities (USEPA, 2006b). Construction of shoreline facilities may involve filling and/or stabilizing (with riprap or other materials) the shoreline, constructing docks, piers or wharfs, draining wetlands, dredging, and channelization of nearshore habitats and adjacent waterways, and clearing large tracts of land for construction of buildings and for materials storage. Significant filling of wetlands also occurred during construction of the Philadelphia Airport. Depending on the industrial process, significant quantities of water may be extracted from the River for use in the manufacturing process or for cooling water. In general, cooling water may be reintroduced to a water body at an elevated temperature, thus reflecting a potential thermal stressor. Chemical contaminants are often associated with industrial facilities, especially those with long-term historical operations. Contaminants either used or produced in product manufacturing enter the environment via spills and leaks, atmospheric release, or past disposal practices. Figures 3-3a–c show the locations of facilities listed in USEPA’s TRI1 database as having reported one or more chemical releases to surface water in 2003. Based on this information, 300 facilities contributed releases to surface water in the Delaware River and its tributaries during 2003. These included 70 to DRBC Zone 2, 110 to DRBC Zone 3 (inclusive of the Schuylkill River), 60 to DRBC Zone 4 (inclusive of the Schuylkill River), and 60 to DRBC Zone 5.

3.2.16 Accidental Spills/Releases

Despite implementation of best management practices, accidental chemical spills, including small- to large-scale oil spills, continue to occur in the Estuary. Following spills, chemicals often reach receiving water bodies either directly or via stormwater. The effects of these releases vary in magnitude depending on the volume and chemical concentrations released. The degree of impact is also determined by the bioavailability and toxicity of the released substance and the sensitivity of the receptors in the affected habitat. Non-chemical spills, such as releases of sewage, can also occur.

1 http://www.epa.gov/tri/

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3.2.17 Sediments

Sediments contaminated with metals and organic compounds can also act as sources (USEPA, 2005), through erosion and re-suspension events followed by transport and eventual re-deposition. Hydrodynamically active areas are likely sources of contaminated sediment to adjacent areas. Sediments in quiescent areas, however, may also act as important vectors to benthic in-fauna and epi-fauna, while ultimately influencing benthic and pelagic organisms (particularly via bioaccumulation through a food chain).. In addition, as new clean sediment is deposited on top of older more contaminated sediment, biological reworking (i.e., bioturbation) within the upper 4–6 in. (deeper in some locations) may cause deeper contaminated sediment to mix with the newer sediment.

3.2.18 Atmospheric Deposition

The deposition of particulates from the air is another potential source of contaminants to rivers and estuaries. Particulates that have settled on land or buildings can be washed by rainfall into streams and storm drains and then be transported to larger water bodies. Atmospheric particulate matter can also be deposited within the Estuary directly. Various chemical stressors that can be transported via atmospheric deposition include polychlorinated biphenyls (PCBs), metals, pesticides, and various petroleum-related and volatile organic compounds (VOCs). Because air-water exchange is a bi-directional equilibrium, it is possible that vapor phase constituents, such as PCBs and nitrogen-related compounds, can “de-gas” from the water column into the atmosphere, thus making the Estuary a “source” and the atmosphere a “sink.” Direct deposition of chemicals into this Estuary from the atmosphere is nonetheless viewed as the dominant direction of air-water exchange.

3.3 Stressor Inventory

An inventory of source categories and associated physical, chemical, and biological stressors for the Estuary is provided in Table 3-1. This inventory table identifies the major stressors associated with each source category; additional, more minor stressors may also exist within each category. It is instructive to evaluate the numbers and types of sources that are associated with physical, chemical, and biological stressors, because it illustrates the complexity of the system and points to the difficulty of pinpointing the effects of individual sources.

A number of sources predominantly associated with urban and industrial development and construction are associated with habitat loss. The most critical habitat loss from the perspective of the Estuary is in the nearshore and adjacent upland areas. These habitat losses are difficult to replace without focused restoration activities. Conventional water quality parameters, including temperature, salinity, dissolved oxygen, and turbidity, are affected by several types of sources. Some of these sources, such as dredging, are short-term, while others are more permanent, such as turbidity associated with runoff.

A broad spectrum of chemical contaminants is associated with the list of sources in Table 3-1. The degree of risk posed by these chemicals depends on many factors, including the concentrations, bioavailability and toxicity of individual chemicals, the presence of multiple chemicals at the same location, and the co-occurrence of chemicals with ecological receptors. Regulatory programs are in place to remediate areas where chemical stressors cause unacceptable risk. However, it is often a difficult and complex challenge to identify the sources of chemicals especially in urbanized and industrialized environments.

Although there are relatively fewer sources of biological stressors in the Estuary, the effect of these stressors can potentially be substantial. Invasive species enter a foreign habitat, such as the

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Estuary, without natural predators or controls on their population. If a food source is available, they can easily create a habitat niche and out-compete native species. This, in turn, may result in either subtle or very significant changes in the structure, function, and overall health of ecological communities. In addition to invasive species, over-harvesting is an additional biological stressor that has left certain stocks of fish and shellfish at levels that are far below those of many decades ago.

This section has provided background on the definition of stressors, the types of stressors, and how stressors may result in adverse impacts to the Estuary. An inventory of regional physical, chemical, and biological stressors is presented in Section 4. In addition, perspective is provided on available information characterizing the spatial and temporal trends of stressors.

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4. Characteristics of Regional Stressors in the Delaware Estuary

This section presents summary information that describes the type, magnitude, and distribution of stressors that have influenced or potentially influenced ecological conditions in the Delaware Estuary under historical and current conditions. Our discussion is divided into three primary subsections that address physical, chemical, and biological stressors. For each potential stressor within these categories, we discuss: 1) the characteristics of the stressor and its relevance to the Estuary, 2) its potential sources, 3) the metrics used to gauge source strength, 4) temporal and spatial trends in its occurrence, and 5) key data gaps and uncertainties that limit the understanding of the degree to which a given stressor influences the ecology of the Estuary.

The intent of this summary is not to provide an exhaustive listing of the available information, but rather to provide sufficient and appropriate information to support the identification and characterization of spatial and temporal trends in the Estuary and provide for a clear understanding of current conditions. As mentioned previously, this information will be used in the subsequent multi-stressor regional risk assessment to be conducted as part of the Delaware River Study. In those instances where information is incomplete or insufficient, data gaps and uncertainties will be clearly articulated. This information can then be used in concert with the results of the regional risk assessment to guide future data collection efforts.

4.1 Physical Stressors

Physical stressors affect plant and animal populations and communities by altering the natural habitat that these species prefer. Based on the compiled information, key physical stressors in the Estuary are as follows:

� Water volume;

� Water temperature;

� Salinity;

� Suspended solids;

� Sedimentation;

� Barriers to fish access; and,

� Habitat loss.

Available information on each of these physical stressors is summarized in the following subsections.

4.1.1 Water Volume

Water volume is an important factor that defines the overall physical environment of the Estuary. It is considered a stressor because changes in volume can directly affect the Estuary’s ecology by inundating, drying, or eroding habitats. Indirect effects may also occur through changes in the physical environment, which in turn lead to other physical and chemical changes that can

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adversely affect ecological communities. For example, rising sea level can inundate wetlands and other low-lying lands, erode beaches, and increase the salinity of the Estuary. Lowered water levels due to drought or increased consumptive water withdrawals can dry wetland habitats, raise water temperatures, and increase tidal amplitudes, which in turn can cause erosion and change wetland hydrological characteristics. Increased water volumes stemming from navigational dredging can lead to greater upstream transport of saline waters and increased tidal heights. Under certain conditions, decreases in water volume (e.g., under drought conditions) may lead to an increase in concentrations of certain chemicals. Conversely, under increased water volume conditions (e.g., wet weather events), chemical concentrations will tend to become more dilute.

4.1.1.1 Sources

Water volume in the Estuary is determined to a large degree by a mass balance of water inputs minus withdrawals. Water inputs are determined by freshwater flow from the Delaware River and tributaries and tidal flow from the Atlantic Ocean. Most changes in water levels are simply the result of natural climatic factors such as drought or flood. However, water withdrawal (removal), consumption (removal without replacement), dredging, and sea level rise all can affect total water volume, and thus change the Estuary’s physical environment.

4.1.1.2 Metrics

Changes to water volume in the Estuary can be gauged by a variety of metrics. These include flow as well as volumes of water removed and consumed. Changes in tidal ranges also indicate changes in water volume, as well as flood frequency, and the occurrence of drought.

4.1.1.3 Temporal and Spatial Trends

Flow in the Estuary is tied significantly to freshwater inputs. An estimated 58% of the freshwater flow to the Estuary comes from the non-tidal Delaware River; another 14% comes directly from the Schuylkill River, while the remaining 28% is from surrounding tributaries and non-point sources (Smullen et al., 1984, as presented in Sutton et al., 1996). The Delaware River at Trenton, NJ exhibits a mean freshwater flow of 319 m3/s (11,280 ft3/s), and a total average flow to the Estuary at the mouth is estimated to be 550 m3/s (19,470 ft3/s). Freshwater flows in the Estuary are summarized in Table 4-1.

As is common among large, lotic water bodies, long period measurements of flow tend to be relatively constant, but year-to-year variability can be significant. Figure 4-1 depicts average annual stream flow at Trenton for the period 1910–1990. As can be seen, total flow is similar across the entire period, but is substantially lowered during small time frames such as during the 1930s, 1960s, and 1980s. These time periods corresponded to times of significant drought. For perspective, Table 4-2 presents a detailed timeline of historical drought and flooding events in the state of DE since the 19th century. Similar information for New Jersey and Pennsylvania was not located. During times of increased precipitation, particularly during flood events, flow can dramatically increase. More typical meteorological conditions result in seasonal patterns, with flow being highest in the spring and lowest in the summer (Table 4-3).

Changes in water use can result in changes to these natural patterns of variability in flow. Increased population growth in areas surrounding the Estuary has resulted in concomitant increases in water use. Billions of gallons of water are withdrawn from the Estuary on a daily basis with millions of gallons being consumed (i.e., not directly returned to the River). Though non-consumptive water use has no net effect on water flow, consumptive water use does. Water withdrawals and consumption from the upper Estuary (corresponding to DRBC Zones 2 and 3) are dominated by electric generating facilities (withdrawals) and public water supply (consumption), whereas those in the lower Estuary (corresponding to DRBC Zones 4 and 5) are

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dominated by electric generating facilities (primarily thermoelectric power stations) (Santoro, 2004). Figures 4-2 and 4-3 depict pie charts of specific uses within total water withdrawal and consumptive use categories as presented by Santoro (2004). The remaining water consumption volumes in the lower Estuary are attributable to industry, agriculture, and public water supply. Estuary-wide, electric generating facilities dominate withdrawals (69% of total) and public water supply, including regional exports to NY and NJ, dominates consumption (81%) (DRBC, 2004; Sutton et al., 1996).

Changes in water volume in the Estuary also can result from dredging activities. The ports of Wilmington, Philadelphia, Camden, and Trenton have historically been economically important to the region and nation. The natural channel depths in the Estuary ranged from 17–24 ft. prior to any dredging activity (Najarian Associates, Inc., 1993). Dredging activity began in 1885 and continued in earnest in the years prior to World War II, resulting in a deepening of the main shipping channel from 26 to 40 ft. A timeline of the dredging activity in the Estuary and maintenance of the main shipping channel is shown in Table 4-4. Since World War II, the main shipping channel has been regularly dredged to maintain the 40 ft. depth, requiring the removal of approximately 4.9 million cubic yards (cy) of sediment annually (USACE, 1997).

The original dredging work, creating the shipping channel, deepened the natural channel and allowed a greater volume of water to enter the Estuary and move upstream (Biggs and Horwitz, 1999; USACE, 1997). The continued maintenance of the shipping channel perpetuates the increased water volume, though it does not increase it further. As a result of the increase, increased tidal heights have occurred. For example, prior to 1910, the average tidal range at Trenton was approximately 4.2 ft. The average tidal range at Trenton under current conditions is 8.25 ft., or approximately two times greater than historical levels. The greatest effects are noted in the upper Estuary because this section has a larger cross section, or conveyance area due to dredging. This larger cross section facilitates greater tidal amplitude (Najarian Associates, Inc., 1993). In addition, increases in tidal height could be exacerbated by decreased freshwater flow due to water withdrawal and or consumptive use in the upstream regions of the Estuary (DELEP, 1996; Sutton et al., 1996). Additional long-term data exist for tidal ranges measured by NOAA’s National Ocean Service from 1921 to 1990 at Lewes, DE, and Philadelphia, PA, while data for Trenton, NJ cover only a more recent period (Najarian Associates, Inc., 1993). The mean tidal range shows a net increase of approximately 1 ft. during this time at Philadelphia (Figure 4-4), with the most noticeable increase occurring between 1930 and 1943, coincident with the period of greatest dredging. No discernible change in tidal height is observable from the Lewes record.

The U.S. Army Corps of Engineers (USACE), Philadelphia District, recently proposed a dredging project to deepen the main shipping channel and channel bends from –40 to –45 ft. The extent of the proposed dredging spans from Philadelphia through the Delaware Bay. The total amount to be dredged during initial project construction is estimated to be approximately 33 million cy (USACE, 1997). Continual maintenance dredging will increase from 4.9 to 6.0 million cy per year with periodic advanced maintenance dredging to depths up to 49 ft. in high shoaling areas (USACE, 1997). Though dredging operations were initially slated to begin by 2002, a number of issues have stalled project initiation. If initiated, this project could further affect tidal amplitude.

In addition to tidal dynamics, an increasing rate of global sea level rise may also result in a greater volume of water in the Estuary. It has been estimated that over the past 2,000 years, global sea level has risen an average of 0.12 cm/yr. Present estimates are substantially greater at 0.33 cm/yr (Delaware DNREC, 1999). USEPA further projects sea level rise as high as 11 ft. by 2100, resulting in significant impacts to Delaware River shoreline communities (Delaware DNREC, 1999). Figure 4-5 shows projected sea level rise throughout the Estuary (noted by

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shaded shoreline areas, Kraft, 1988 as presented in Sutton et al., 1996). In the ecological context, sea level rise can be a stressor of great consequence. Rising waters lead to permanent inundation of low-lying areas which, over time, changes the position of the shoreline and drowns natural habitats. Ecological communities will shift in response to these changes. For perspective, on a national basis, up to 65% of the coastal marsh of the contiguous U.S. might be lost due to sea level rise by the year 2100 (Sutton et al., 1996; Wetlands Research Associates, Inc., 1995; Kraft et al., 1992). Long-term sea level rise is also projected to result in a shift in salinity regimes, though the precise magnitude and spatial extent of this and resultant saltwater intrusion in the Estuary is currently unknown.

4.1.1.4 Data / Information Gaps and Uncertainties

Long-term and seasonal patterns of flow in the Estuary due to natural climatic conditions are well documented. The impact of water consumption on total flow has also been documented although projections of the precise magnitude of decreased flow in response to increased consumption was not identified among the available literature. The impact of shipping channel dredging on water volume and tidal flow is also well documented based on historical observation and modeling. Less well understood and characterized, however, is the potential magnitude of saltwater intrusion as a consequence of long-term sea level rise.

The role of water volume in defining the physical environment within the Estuary is significant. Kreeger et al. (2006) called for the development of an updated hydrodynamic model for the entire Estuary that could help explain the actions and interactions of all components of the system. Such a model would greatly add to the strength of our understanding of these complex interactions on both regional and local scales.

4.1.2 Water Temperature

Water temperature is a physical stressor because it may dictate or influence various physical, chemical, and biological properties that may directly or indirectly affect aquatic life in an adverse way. Excessive temperatures can be directly harmful to temperature-sensitive aquatic life. All aquatic organisms have optimal temperature ranges for biological processes, and a shifting temperature regime can result in a corresponding shift in species composition towards a group better suited for the new conditions. In addition, water quality is negatively influenced by excessive temperature increases, which can cause decreased oxygen saturation in water and increased activity of algae and bacteria. In fact, DRBC (2004) has stated that regional temperature exceedances in urbanized portions of the Estuary can pose unacceptable risks to biota.

4.1.2.1 Sources

Changes in seasonal water temperature patterns throughout the Estuary are primarily the result of natural conditions of surface water flow and depth. Patterns of water temperature follow seasonal and spatial trends partly reflecting proximity to freshwater inflow and water depth. Drought conditions can exacerbate temperature increases, with water temperatures increasing as water depths decreases. Since 1930, various periods of major drought conditions have been noted in DE spanning more than 30 cumulative years, including the 1930s, 1960s, and 1980s (Sutton et al., 1996; USGS, No Date). Though specific instances of elevated water temperatures in the Estuary during those times were not identified in the available literature, it very probably occurred. More recently, DRBC (2004) has noted drought-related temperature increases as a source of impairment in Zones 3 and 4 of the Estuary. The rate of temperature change is another possible stressor in the Estuary, especially in shallow areas prone to wide temperature regimes from day-day which can be exacerbated by drought conditions. Long-term temperature increase is a

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potential stressor as well. Species composition may shift with certain organisms colonizing northern latitudes due to optimal conditions changing geographically from increasing temperatures.

Regional water use also can influence water temperatures as a consequence of lowering water levels in the Estuary. As mentioned in the previous section, billions of gallons of water are withdrawn from the Estuary on a daily basis with millions of gallons being consumed (i.e., not directly returned to the River). Explicit data that tracks water temperature in the Estuary as a function of water use was not located in the available literature, though it is reasonable to assume that increased water consumption contributes to lowered water levels, which under certain conditions, can result in elevated temperatures.

Direct discharge of heated water to the Estuary also can result in temperature stress, though this would be expected to occur on a localized scale. Currently, there are 15 electric generating facilities operating on the shorelines of the Estuary, including two nuclear power facilities in the Delaware Bay (Salem and Hope Creek facilities) (USEPA, 2006b). Large quantities of surface water are withdrawn by these facilities and used for cooling water and then discharged back into the Estuary. Under the current regulatory environment, if effluent temperatures are predicted to pose unacceptable risk to the surrounding ecosystems, cooling towers are built to moderate thermal discharges. No comprehensive documents addressing thermal discharges by major facilities in the Estuary were located in the published state or federal literature.

4.1.2.2 Metrics

Measurement of water temperature is the metric by which this stressor is gauged. The discussion of water temperature in the Estuary will focus on general water temperature trends combined with DRBC guidelines. DRBC (2004) has established a number of temperature criteria for particular zones within the Estuary. These criteria are listed in Table 4-5.

4.1.2.3 Temporal and Spatial Trends

Water temperature in the Estuary is influenced by a variety of factors including local meteorological conditions, water depth, temperature of adjacent coastal waters and inflowing tributaries, estuarine mixing, and industrial thermal discharges (Biggs and Horwitz, 1999). The following discussion of temporal and spatial trends is based primarily on monitoring syntheses presented in Biggs and Horwitz (1999).

4.1.2.3.1 Temporal Trends

Water temperatures in the Estuary are seasonally dynamic. Winter water temperatures in the Delaware River are highest near the mouth of the Delaware Bay, and lowest near the upper Estuary (Trenton, Zone 2) due to cold freshwater inflow. In spring and summer, this trend is reversed with the warmest water found in the upper Estuary and coldest water found near the mouth of the Bay. Transverse seasonal gradients in water temperature also exist throughout the Estuary as observed by comparing the main channel with the shoreline including tidal creeks and marshes. During the spring and summer, water temperatures are typically warmer in the littoral zones of the Estuary than the main channel, while fall and winter months show an opposite trend.

There is no indication of any long-term trends in these seasonal changes. Figure 4-6 shows an example trend of water temperature at the U.S. Geological Survey (USGS) Benjamin Franklin Bridge monitoring site near Philadelphia (Zone 3) (Krejmas et al., 2005). Monthly mean temperature in 2001 compares almost identically to long-term monthly mean temperatures for the period from 1964 to 2000, with lowest temperatures recorded in April (10–11°C) and peak

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temperatures observed in August (approximately 26–27°C). General water temperatures range from 0°C in the winter to >30°C in the summer, depending on longitudinal location (Biggs and Horwitz, 1999).

Other information on temporal trends throughout the Estuary was not found. Furthermore, the influence of droughts on Estuary-wide water temperature has not been well characterized, nor has the influence of water withdrawals on temperature patterns.

4.1.2.3.2 Spatial Trends

Water temperatures also vary spatially due to differences in water depth, flow rates, and water sources (e.g., shallow versus deep tributaries). A longitudinal trend persists throughout the Estuary with upper portions (e.g., Trenton) showing warmer temperatures in the summer and colder temperatures in the winter due to freshwater inflow. Trenton exhibits the maximum observed temperature range in the main-stem of the Estuary, with temperatures varying from 0 to >30°C (Biggs and Horwitz, 1999). Likewise, a lateral trend is observed in the Estuary when comparing littoral zones with the main channel. Temperatures in nearshore areas and tidal creeks may exceed that in the deeper portions of the Estuary by as much as 4°C in the summer, but be considerably colder than the main channel in the winter (Biggs and Horwitz, 1999). Shoreline temperatures during the summer can stratify due to temperature discrepancy with surface and bottom depths. This, in turn, may inhibit nutrient circulation throughout the water column.

In addition to these spatial trends linked to natural flow and water depth conditions in the Estuary, monitoring data and analysis conducted by DRBC (2004) suggest that other sources could be adversely affecting water temperatures in DRBC Zones 3 and 4 of the Estuary. DRBC (2004) reported that water temperatures in Zones 3 and 4 are sufficiently high to adversely impact aquatic life, with >10% of temperature measurements collected during 2000 to 2002 exceeding criteria in Zones 3 and 4 (DRBC, 2004). DRBC (2004) hypothesized that these temperature impairments could be due to drought conditions as well as generalized impacts associated with urbanized and high density areas. No other spatial trends were apparent in the available data.

4.1.2.4 Data/Information Gaps and Uncertainties

Overall, limited information is available to fully discriminate between natural and anthropogenic sources of temperature stress. Temperature response to drought conditions, though conceptually understood, has not been quantified Estuary-wide. The influence of water consumption on water levels and subsequent temperature characteristics also has not been quantified.

Insufficient data are available to assess spatial temperature trends throughout the Estuary due to anthropogenic sources. Some data summarized by DRBC suggests that urban/industrialized areas in Zones 2 and 3 might experience temperature increases during drought conditions, but too few data have been published to assess this spatial trend with certainty.

Readily available data also are lacking with which to evaluate more localized impacts of electric generating facilities or other industrial cooling water discharges.

Nevertheless, there is no indication that water temperatures are on the rise in the Estuary. The one study (Krejmas et al., 2005) for which adequate long-term data were available revealed no temporal trends.

Kreeger et al. (2006) called for the development of an updated hydrodynamic model for the entire Estuary, which could help explain the actions and interactions of all components of the system,

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including temperature along with flow and salinity data. Such a model would greatly add to the strength of our understanding of these complex interactions on both regional and local scales.

4.1.3 Salinity

Salinity is a significant controlling factor for the ecology of the Estuary. Salinity distribution affects the aquatic and wetland habitats that exist in various reaches of the Estuary and the species that can inhabit or utilize these habitats. This is because plant and animal species are adapted to specific salinity levels and struggle to persist when conditions are outside those ranges.

To a large degree, salinity variation throughout the Estuary is a natural phenomenon caused by the interaction of the tidal flow from the Atlantic Ocean and the freshwater flows from the main-stem Delaware River and its tributaries. A north-south trend of increasing salinity exists in the Estuary, and is designated within three ecological zones. The upper zone of the Estuary is a freshwater tidal zone and extends from the head of tide at Trenton, NJ, to Marcus Hook (River Miles 80–133). A transitional zone, extending from about Marcus Hook to Artificial Island (River Miles 54–80) has a wide salinity range (about 0–15 ppth), depending on the tide and freshwater flows in the river. The lower zone is the Delaware Bay, which is a large open embayment (River Miles 0–54) with saline waters that extends to the Atlantic Ocean. The salinity range in the Estuary is from less than about 0.3 ppth (i.e., freshwater) at Trenton to about 28–31 ppth (saltwater) at Cape Henlopen. The transition zone in the Estuary shows the greatest variability in salinity. A diagram showing typical high and low flow salinity distribution provided in Figure 4-7.

Although the net flow of the Estuary tends to carry saltwater toward the ocean, tidal currents carry saltwater upstream, where it mixes with freshwater. Differences in the densities of saltwater and freshwater also contribute to saltwater intrusion; heavy saltwater on the bottom tends to move upstream when adjacent to lighter freshwater, forming a wedge.

Changes in water levels and general hydrodynamics, however, can cause the natural patterns of salinity in the Estuary to change. When this occurs, resident plants and animals not adapted to the new conditions can become stressed and may be replaced in part or in whole by more tolerant species. This can result in shifts in the nature and character of resident ecological communities.

4.1.3.1 Sources

The source of salinity in the Estuary is the Atlantic Ocean.

4.1.3.2 Metrics

Salinity is a measure of the total salt content in water, typically expressed in concentration units of parts per thousand. The upstream movement of saline water in the Estuary is tracked by movement of what is commonly referred to as the “salt line.”. The location of the salt line is defined as the 7-day average of the 250 parts per million (ppm) isochlor.

4.1.3.3 Temporal and Spatial Trends

Salinity patterns in the Estuary are temporally variable on both an annual and long-term basis. Annual variation in overall salinity and the upstream movement of the salt line is influenced largely by natural climatic conditions related to precipitation. During dry seasons and periods of low stream flow, salinity in the system increases and the salt line can move northward.

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The freshwater inflow to the Estuary comes primarily from the Delaware River upstream of Trenton, and the Schuylkill River at Philadelphia. Sutton et al. (1996) estimated that the net freshwater inflow to the Estuary and Bay represents approximately 5.6 trillion gallons per year. This freshwater input is mainly the result of precipitation and is the primary factor affecting salinity distributions in the Estuary. In general, large freshwater inflows push the saline water seaward in surface waters and decrease salinity throughout the Estuary, whereas low-flow or drought conditions increase salinity and allow intrusion of saline water from the Delaware Bay upstream in bottom waters (Sutton et al., 1996). The resulting annual fluctuation of the salt line (i.e., 250 ppm isochlor) is depicted in Figure 4-8. Based on these data, the furthest upstream movement of the salt line is to River Mile 89, which is located in DRBC Zone 4.

Major floods and droughts can have dramatic effects on stream flow, thereby changing the location of the salt line and increasing or decreasing salinity concentrations within the Estuary. Floods in the Delaware River region have been widespread, with severe floods documented in 1846, 1933, 1947, 1955, 1960, 1962, 1967, 1972, 1979, and 1989 (USGS, No Date). Severe droughts, persisting several years, occurred in the 1930s, 1960s, and 1980s (Sutton et al., 1996; USGS, No Date). These major hydrologic events are summarized in Table 4-2 (USGS, No Date). DRBC observed movements of the salt line in the Delaware River during 1999–2003, and found an upstream migration during drought conditions (1999, 2001–2002) and a substantial downstream retreat during wet periods (2000, 2003) (Santoro, 2004).

Superimposed on these natural patterns of salinity distribution is the upstream encroachment of the salt line over time. According to Smullen et al. (1984) and DELEP (1996), saline water intrusions upstream in the Estuary have been increasing over the last 50 years, as a result of drought conditions, water withdrawals, deepening of the shipping channel, and sea level rise.

Water withdrawal with subsequent consumption can contribute to increased salinity because it decreases freshwater flow. Figure 4-9 illustrates water use within the Estuary (Albert and Pollison, 1989 as presented in Sutton et al., 1996). Surface water withdrawals account for approximately 39% (2.2 trillion gallons) of total water use. Of these surface withdrawals, 23% are used for domestic and industrial purposes, whereas the other 77% is used for power generation. Based on data from the early to mid-1990s, total water withdrawals appear to be increasing slightly, but water consumption (withdrawal without replacement) appears to be increasing dramatically (Table 4-6). From 1990 to 1996, water consumption increased more than 200%, from 334 million gallons per day (mgd) in 1990 to 1,027 mgd in 1996 (DRBC, 2004; Sutton et al., 1996). DRBC actively manages flows in the Estuary to control salinity encroachment and has taken measures to ensure that consumptive water uses do not adversely affect flow and hence contribute to saltwater intrusion.

The maintenance of the shipping channel has also been implicated as a potential factor contributing to saltwater intrusion in the Estuary. As previously detailed, the shipping channel is maintained at a depth of 40 ft. to allow passage of ships from the Delaware Bay to the Philadelphia area ports. Maintenance of the shipping channel has resulted in salinity shifts by allowing a greater volume of seawater to move upstream (Sutton et al., 1996). A 5-ft. deepening project of the Delaware River shipping channel has recently been proposed. An assessment was performed by USACE to quantify potential impacts of the proposed deepening on spatial and temporal salinity distributions. It was concluded from this study that deepening the shipping channel from 40 to 45 ft. would result in minimal salinity increases in the Philadelphia area, and would not have adverse impacts on water supplies, though upstream intrusion of approximately up to four miles was predicted using the USACE 3-dimensional hydrodynamic and salinity model

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(USACE, 19972). The impact on saltwater intrusion of potential future (and as yet to be defined) dredging programs is unknown, but could conceivably track historical trends.

Perhaps on a more significant spatial scale, long-term variations in sea level also are expected to affect salinity intrusion in the Estuary (Smullen et al., 1984). A rise in sea level affects the location of the salt line by pushing it farther upstream which, in turn, can result in saltwater intrusion into aquifers, higher water treatment costs for water suppliers, and higher corrosion control costs for industries (Santoro, 2004; USACE, 1997; Sutton et al., 1996; Smullen et al., 1984). In ecological terms, as sea level rises and estuarine and wetland salinities increase, coastal vegetation will likely undergo changes in community composition, notably with an increase in more salt-tolerant plant species while intolerant plant species are forced further inland. These changes in vegetation will likely modify fish and wildlife populations adapted to specific plant associations (Cooper et al., 2005). Hull and Titus (1986) predicted that sea level rise could substantially increase the salinity of the Estuary in the 21st century. They predicted that without any countermeasures, a combination of severe drought (i.e., akin to that in the early 1960s) and sea level rise could send the salt line upstream to River Mile 100, compared with approximately River Mile 90 under present sea level conditions. More recently, Cooper et al. (2005) reiterated the threat of saltwater intrusion in the Estuary consequent with sea level rise, with subsequent alterations in the shoreline habitats and biota that inhabit them. An increase in salinity also has the potential to negatively influence economically-important organisms in the Estuary, such as the oyster, and this concern helps fuel regular saltwater intrusion management (Sharp, personal communication).

4.1.3.4 Data/Information Gaps and Uncertainties

Overall, the available data support a relatively robust understanding of salinity distribution in the Estuary as a function of water flows resulting from natural seasonal variations and episodic events (e.g., drought, flood). Continued increases in consumptive water withdrawals can additionally facilitate saltwater intrusion, though projections of the precise magnitude of salinity intrusion as a result of increased consumptive withdrawals have not been published. Dredging of the shipping channel has contributed to some long-term upstream encroachment of the salt line, and planned dredging could contribute to further encroachment.

Less well understood and characterized, however, is the potential magnitude of saltwater intrusion as a consequence of long-term sea level rise. Many researchers agree that sea level rise is occurring and will be associated with increased saltwater intrusion in the Estuary. The magnitude of that impact can be approximated only by modeling, but is potentially significant. The accuracy of existing models to predict saltwater intrusion as a result of sea level rise is unknown.

4.1.4 Suspended Solids

Suspended solids are particles that are present in the water column. They can consist of silt, clay, sand, finely divided organic matter, and plankton and other microscopic organisms. Suspended solids can influence biological productivity throughout a water body by reducing the amount of light passing through the water column (thereby reducing primary production). Suspended solids can also serve as a chemical stressor source by adsorbing hydrophobic chemicals. In the Estuary, maximum turbidity (a measurement of water cloudiness used to relate suspended solids) occurs from the southern industrialized corridor downstream to Zone 5, and consists mostly of inorganic

2 Also found at http://www.nap.usace.army.mil/cenap-pl/8studies.htm

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total suspended solids loads that enter the river system via natural processes as well as the downstream transport of resuspended bottom sediment. Suspended solids present in the water are largely a function of sediment flux within the Estuary.

4.1.4.1 Sources

The Estuary is a naturally turbid water body, likely due to the fact that it is very well mixed and hydrodynamically active, thus leading to the constant reworking and resuspension of bottom sediment (Kreeger et al., 2006; Walsh, 2004). Sediment influx leading to suspended solids is mostly from main-stem and tributary river sources, with levels of suspended solids relatively constant since the 1960s (Santoro, 2004). Natural processes are the dominant influence on turbidity dynamics with tidal strength causing high suspended sediment concentrations along the estuarine turbidity maximum (ETM), which is located south of the industrial corridor of the Estuary down to Zone 5 (Zones 4-5). Though bottom sediment resuspension is believed to be the predominant source of turbidity in the Estuary, Santoro (2004) estimates as much as 50% of the annual sediment load entering the Estuary is supplied from runoff and elevated stream flow during the rainy season. Other factors contributing to turbidity include general stratification, seaward residual current, and tidal pumping (Cook et al., in press; Santoro, 2004; Walsh, 2004; Sanford et al., 2001; Jay and Musiak, 1994). The position of the ETM might also be influenced by the future migration of the salt line (see Section 4.1.3) potentially associated with dredging measures and freshwater inflow.

Mansue and Commings (1974) and Biggs et al. (1983) estimated that approximately 1.5–2 million tons of fluvial sediment enters the Estuary annually, massively contributing to total suspended sediment amounts. It is also shown that bottom erosion can significantly contribute to suspended sediment as well (Cook et al., in press; Walsh, 2004). Walsh (2004) estimates that as much as 72% of sediment sources in the Estuary can result from bottom erosion, thus leading to resuspension in the water column. The majority of suspended matter throughout the ETM is inorganic; Cifuentes (1991) reported percent organic carbon levels at <10% in the industrial corridor. Similarly, Mansue and Commings (1974) estimated that approximately 12% of suspended sediment in the Estuary reflected organic materials, with the inorganic sediment represented by silt (53%), clay (43%), and sand (4%).

4.1.4.2 Metrics

The dominant metrics used to measure suspended solids in the Estuary are total suspended solids (TSS), turbidity, and seston concentrations. TSS refers solely to the inorganic sediment suspended in water. Turbidity refers to the amount of cloudiness or haziness in water, and is measured as a function of the behavior of light passing though water (either as attenuation or deflection). Seston is defined as the total weight of inorganic suspended sediment and organic constituents including chlorophyll and particulate organic carbon removed from water samples via filtration (Biggs et al., 1983).

4.1.4.3 Temporal and Spatial Trends

Suspended solids vary both spatially and temporally in the Estuary, primarily due to natural processes. Biggs and Horwitz (1999) summarized DRBC TSS monitoring data collected biweekly from 1971 to 1998 at two sampling stations near River Mile 50. Over the course of the sampling period, the highest TSS ranges typically occurred in May, and the lowest ranges occurred during December through February. The median TSS concentration during this time was 40 mg/L, and the observed range was 10–130 mg/L. Pennock (1985) showed seasonal variability of suspended solids across the Estuary. The largest suspended sediment concentration

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was observed in the upper Estuary near the industrial corridor during the spring, probably due to rain activity and stormwater runoff increasing sediment loadings (Pennock, 1985).

Seston values throughout the Delaware River have been observed to range from less than 1 to >200 mg/L with the highest levels found in Zone 5 (Biggs et al., 1983). Figure 4-10 shows surface water seston concentrations with distance from the mouth of the Delaware Bay (Biggs et al., 1983). Seston in Zone 5 is relatively high, ranging from 20 to 140 mg/L, though these values are lower than adjoining tributaries (approximately 230 mg/L; Biggs et al., 1983). Bottom water seston concentrations are also higher than at shallower depths (Biggs et al., 1983). This increase in concentrations near the river bottom is a result of resuspended sediments from strong tidal currents, particularly apparent south of the industrial zone (Biggs et al., 1983; Najarian Associates, Inc., 1993). Najarian Associates, Inc. (1993) identified an increase in tidal strength from Philadelphia to Trenton from 1910 to 1990 as a result of regular dredging maintenance.

Sharp (personal communication) presents long-term turbidity data from research cruises throughout the entire Delaware Estuary in which Zone 5 (~ River Mile 60) showed seston concentration maxima probably from sediment resuspension (Figure 4-11). Cook et al. (in press) further observed an increased sediment flux downstream of the Estuary that was significantly larger than estimated influx from river tributaries (11 x 108 kg versus 5 x 108 kg). Such a mass imbalance implies eroded bed sediment as a major source of suspended solids to the ETM.

The high turbidity in the Estuary is believed be a limiting factor on primary productivity. The Estuary is a nutrient-rich system, and high nutrient levels are typically associated with increased algal biomass, increased levels of bacterial degradation, and a commensurate decrease in levels of dissolved oxygen, a condition known as eutrophication. However, despite high levels of nutrients in the Estuary, eutrophication has not been reported (Santoro, 2004; Sutton et al., 1996; Sanders and Riedel, 1992). Light limitation due to turbidity has been suggested by some as the most likely explanation (Marshall, 1992), though overall reduced bioavailability of the nutrients present in the system is also a possibility. USEPA (2004) reported that water clarity in the Estuary was substantially less than other northeast U.S. estuaries, with only about 5% of incident light (on average) reaching 1 m in depth. Chlorophyll-a is used as an index of algal biomass and thus as an indicator of possible eutrophic conditions. Sharp (personal communication) observed a relative decrease in chlorophyll-a concentrations near the ETM across seasons during a long-term Estuary-wide monitoring program from 1978-2003 (Figure 4-12).

Recent chlorophyll-a levels were reported to average around 6 µg/L in the shipping channel of the Estuary and 9 µg/L at stations outside of the shipping channel (Santoro, 2004). Kiddon et al. (2003) classified areas having chlorophyll-a concentrations of greater than 15 µg/L as “degraded,” and reported somewhat different results. These authors classified 24% of the Bay, 63% of the tidal portion of the Delaware River, 20% of the tidal portion of the Schuylkill River, and 100% of the tidal portion of the Salem River as “degraded” due to high levels of chlorophyll-a.

4.1.4.4 Data/Information Gaps and Uncertainties

The available data are sufficient to understand the general patterns of the distribution of suspended solids in the Estuary. The collective literature indicates that the Estuary is a naturally turbid water body, with levels of TSS/seston occurring at highest levels downstream of the industrial corridor. The industrial corridor itself is also prone to high turbidity due to stormwater input from adjoining urban areas as well as rain events. There are natural seasonal variations that are tied to precipitation and increased flow in the system.

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A comprehensive quantitative understanding of turbidity, sedimentation, and the sediment budget for the Estuary is currently lacking. Recent research by Cook et al. (in press) and Walsh (2004), along with unpublished data by Sharp (personal communication), have provided important data for better understanding particulate sources and transport in the Estuary. More information would further our understanding. Kreeger et al. (2006) concluded that insufficient data are available to fully elucidate the interrelationship between sediment inputs, turbidity, and light availability (physical traits), nutrient concentration and balance (chemistry), contaminant forms and concentrations (chemistry), and the relative production of autotrophs (phytoplankton) and heterotrophs (bacteria) that represent the base of the food chain.

4.1.5 Sedimentation

Sedimentation is the process by which sediments moving within the water body are deposited onto the bottom. Sedimentation is a stressor because deposited sediment can alter the ecological community by directly changing the physical environment in the depositional area. In fact, sedimentation in combination with salinity dynamics is believed to be the dominant influence on habitat within the Estuary (Santoro, 2004).

4.1.5.1 Sources

A number of physical processes directly affect sedimentation in the Estuary, including sediment load entering the Estuary, hydrodynamics, and dredging. A range of crude estimates of sediment load entering the Estuary have been made. Biggs et al. (1983) presents a total sediment budget of approximately 3 million tons of sediment input to the Estuary with 68% from upland rivers, or approximately 2 million tons (Table 4-7). This amount compares favorably with a prior estimate of 1.5 million tons for fluvial transport of sediment, with the majority originating from the northern Delaware River main-stem above Trenton (56%), the Schuylkill River (20%), and the Christina River (9%) (Santoro, 2004; Mansue and Commings, 1974). Biggs et al. (1983) shows that in addition to fluvial sediment transport, shore erosion, dredging leakage, and phytoplankton production each contribute 5–10% to sedimentation inputs.

These initial sediment budget estimates did not reasonably account for the Estuary itself as a potential sediment source, since resuspension and benthic erosion can have significant impacts on sediment dynamics in a system. Walsh (2004), for example, observed bottom erosion as a major source of fine-grained sediment in the Estuary with an estimated annual supply of 3.4 x 109 kg/yr of sediment versus 1.3 x 109 kg/yr coming from river input. Internal sediment sources consequently have significant implications on the sediment budget.

4.1.5.2 Metrics

The dominant metric used for evaluating sedimentation is annual sediment loading. We did not find much information in the literature that discussed spatial and temporal (i.e., year-to-year long-term) patterns to sedimentation. Therefore, we relied on indirect measures to explore these trends. Sediment grain size was used to identify the spatial distribution of depositional environments across the Estuary, and dredge volumes were used to provide an indirect measure of sedimentation changes over time.

4.1.5.3 Temporal and Spatial Trends

Sedimentation occurs throughout the Estuary, and bottom sediment types span the full range of grain size. Fine-grained sediment accumulations are typically interpreted to indicate depositional areas and coarse-grained sediments are used to indicate high-energy erosion areas. Figures 4-13

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and 4-14 depict the distribution of sediments types and depositional areas throughout the industrialized corridor within the Estuary. As can be seen from the accompanying sediment core photographs, the areas near Philadelphia consist of coarser sediment (sand/gravel) with no fine-grained deposition, whereas the downstream area near Wilmington consists of finer clays indicating depositional areas. This transition suggests the lower portion of the Estuary is depositional in nature and the upriver area is more dynamic and sufficiently energetic to constantly rework sediments (Santoro, 2004). Sediment consisting of sand is confined mostly to the lower half of the Estuary, adjacent to the Delaware Bay. Deposition occurs in other areas as well. These results parallel the findings of Sommerfield and Madsen (2003) who observed a down-Estuary transition from coarse-grained sand and gravel to fine-grained clays and silts to occur between River Miles 75-85 (boundary of Zones 4-5). Like Santoro (2004), Sommerfield and Madsen (2003) also observed reworked bottom sediment to dominate the general sedimentary environment of the Estuary.

In addition to these areas, sedimentation also occurs in the shipping channel and in nearshore anchorage/berthing areas in ports. As a result, dredging is required to remove sediments and return the bottom to the necessary navigational depth. This occurs on a regular basis, and because of this, dredging volumes can provide an indirect measure of sediment loading in the Estuary. Dredging activity in the Estuary has focused on the maintenance of a 40 ft. shipping channel from Philadelphia through the Delaware Bay since 1938. Fine-grained sediment accumulation within subtidal waters of the Estuary have been found to occur at discrete centers of deposition limited to the Marcus Hook-New Castle reach (Zones 4-5; Sommerfield and Madsen, 2003). This area is believed to be the most sediment-rich of the Estuary requiring annual dredging maintenance, in which >60% of all dredged sediment from the shipping channel is derived from this reach (Sommerfield and Madsen, 2003). Dredged sediment volume from 1938–1968 across the entire shipping channel was estimated at approximately 54,000,000 cy, or an estimated 1.8 million cy of sediment dredged annually (USACE, 1992, 1950). This operation included the dredging of five anchorages. From 1968 to 1992, the same dredging operations required an average annual maintenance of approximately 8 million cy of sediment, and the current amount from 1992 to the present is an estimated 5.4 million cy annually (USACE, 1997, 1992). These data suggest higher sedimentation in the Estuary under present day conditions than in the 1960s and prior decades.

4.1.5.4 Data / Information Gaps and Uncertainties

Sedimentation is a continuous and dynamic process in the Estuary. As explained by Sommerfield and Madsen (2003), long-term monitoring of sedimentation, sediment movement, and other physical processes is lacking. Consequently, historical and current conditions across space and time are not specifically characterized. Additional data are needed to more fully understand the manner in which sedimentation occurs across the Estuary over time in order to create a more detailed and accurate sediment budget.

4.1.6 Barriers to Fish Access

Barriers to fish access represent a potential stressor to the Estuary. Overall, this stressor occurs in the Estuary tributaries where dams and weirs are present. These structures can impede access of Estuary fish that use the tributaries for spawning. Limited detailed information is available to separately discuss metrics and spatial and temporal trends of this stressor, so a collective discussion is provided below.

The Delaware River is the “last major free-flowing river east of the Mississippi” (Albert, 1987). There are no dams present in the main-stem Delaware River, and there never have been any located in the Estuary. The only dam ever constructed on the River was located at Lackawanna,

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PA (more than 100 miles upstream of the Estuary).3 However, several of the tidal tributaries to the River have been repeatedly dammed for a variety of reasons, typically for industrial purposes and water supply, beginning as early as the 18th century. Dams create a physical obstruction to spawning runs of anadromous fish such as American shad, blueback herring, alewife, and other species. Anadromous fish migrate from marine or estuarine waters into fresh water streams to spawn. The spawning and development of these species can be adversely affected by the construction of dams or other obstructions that block spawning runs. Dams can also impede the migration of catadromous fish, including the American eel, as these organisms spawn in marine systems and re-enter freshwater/estuarine environments. Dams therefore limit the ability of catadromous fish to utilize upper reaches of tributaries after spawning.

The best metric by which to assess the distribution and magnitude of this stressor is to identify the amount (in acres or miles) of upstream habitat that cannot be accessed by migratory fish because of dams. We did not uncover information on this metric in the publicly available data nor did we find an inventory of all dams located within the Estuary watershed. Consequently, the precise magnitude and spatial distribution of this stressor is not known. However, the magnitude of this stressor is considered potentially significant based upon previously directed restoration efforts. For example, PSEG has played a significant role in the Estuary Enhancement Program by building fish ladders on tributaries in NJ and DE. The ladders are intended to increase alewife and herring access to historical spawning areas closed off by dams. The first ladder was installed in 1996. Since that time, fish use has continually increased and spawning has been observed above the impoundments (PSEG, 2004). Table 4-8 shows the location of fish ladders placed by PSEG in NJ and DE and provides estimates of the amount of habitat made accessible to anadromous fish as a result. The amount of remaining habitat that is inaccessible to anadromous fish is unknown. Additional data are needed to better characterize the magnitude and distribution of this stressor under current conditions across the Estuary.

4.1.7 Habitat Loss

From an ecological context, habitat is the one principal defining element for determining the ecological community in a given area. Numerous habitat types are present in the Estuary, as discussed in detail in ARCADIS BBL and Integral (2007). Table 4-9 lists the primary habitat types within the Estuary. This section focuses on habitat loss as a key stressor defining the current and historical character of the Estuary. Habitat loss in this context is defined as the physical elimination or alteration of the natural habitat.

This section also focuses on habitat loss in wetland, aquatic, and nearshore areas, because these areas are the most significant for defining the ecological community of the Estuary. Habitat loss in upland areas is considered a more relevant indicator of overall urbanization and industrialization, and the multitude of stressors associated with this are separately assessed in other parts of this section. In addition, habitat alteration due to chemical conditions is addressed separately in other sections.

There is a substantial amount of information in the published literature that documents habitat loss and current conditions in the Estuary (ARCADIS BBL and Integral, 2007). This section draws largely upon the previous historical and current ecology report (ARCADIS BBL and Integral, 2007) to provide a focused summary of the available data as well as perspective on the extent of habitat loss in the Estuary and significant historical and regional trends. This information will be used to evaluate the relative regional importance of habitat loss as a stressor.

3 This dam was built between 1825 and 1828 and lasted into the early 20th century.

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The extensive literature, as well as the overall synthesis presented in ARCADIS BBL and Integral (2007), should be consulted directly for specific details.

4.1.7.1 Sources

There are a number of important sources of habitat loss in the Estuary. Large-scale conversions of wetlands for agriculture and filling for development and highway construction have traditionally been the greatest causes of wetland loss in the Estuary. Other key impacts include port construction, dredging, and dredge material disposal, suburban subdivisions, borrow pits for sand and gravel mining, impounding water for water supply, waterfowl impoundments, and mosquito ditching (Tiner, 2001; Delaware DNREC, 1999). In the future, sea level rise may also cause wetlands loss and changes (Sutton et al., 1996).

Mosquito ditching was a method of mosquito control initiated during the Great Depression under the Civilian Conservation Corps. The process created a series of parallel ditches about 150 ft. apart in wetlands where mosquito breeding was considered prolific. It was thought that draining these areas would suppress mosquito populations. This process drastically impacted hydrology, yielding drier lands with standing pooled areas of water. The altered hydrology caused a shift in vegetation from low marsh to high marsh or upland vegetation (Delaware DNREC, 1999; Wetlands Research Associates, Inc., 1995).

Dredging and channel maintenance are necessary to maintain the shipping channel. Due to deepening of the channel, the upper and lower portions of the Estuary have undergone noticeable changes. As previously described, tidal fluctuations have increased in the upper portions of the Estuary (Delaware DNREC, 1999). In addition, increased inundation into upper marsh habitat, and increasing salinity levels significantly impact the vegetation and wildlife relying on the freshwater tidal marsh of the upper Estuary. The entire Estuary is also impacted by changes in salinity, turbidity, and oxygen levels after dredging. In addition, placement of dredged material has been associated with wetland filling (Delaware DNREC, 1999).

Increasing rate of global sea level rise is a contemporary concern. It is estimated that over the past 2000 years, sea level has risen an average of 0.12 cm/yr. With an increase in sea level rise associated with global climate change, present estimates are substantially greater at 0.33 cm/yr. With continuing rates, it is expected that by 2100, the sea will have risen another meter and eradicated 65% of the coastal marshes of the contiguous U.S. (Sutton et al., 1996; Wetlands Research Associates, Inc., 1995; Kraft et al., 1992).

Studies have already begun to examine the changes in the tidal wetlands along the Estuary. One study by Field and Phillip (2000) examined the changes between Chester, PA, and Trenton, NJ, by comparing aerial photos of the late 1970s and late 1990s. They used vegetation as a signal for tidal duration and depth and relative elevation of the marsh. Between the two time periods, the amount of marsh land remained relatively the same in both locales, but there was an increase in low marsh from 9% in 1977/1978 to 34% in 1997/1998. This change is attributed to altered hydrology in the area affecting the system’s ability to counteract the effects of sea level rise with matching sediment accretion (Field and Phillip, 2000).

Factors other than physical removal or destruction contribute to habitat loss. For example, the spread of the invasive form of the common reed Phragmites australis is one well known problem throughout the Estuary. It is most associated with disturbed areas and edges including dredged material placement areas. Large placement areas, such as Philadelphia Airport and Killcohook and Artificial Islands may offer conditions suitable for the spread and dominance of the common

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reed. The impacts and benefits of common reed have been widely debated. Although it is known to increase water quality and create stable banks, it creates monotypic stands that differ in composition and structure of native wetlands, and are thus far less desirable for certain endemic wildlife in the Estuary (Wetlands Research Associates, Inc., 1995).

Snow goose grazing has also become a problem within the Estuary. The geese feed on the rhizomes of smooth cordgrass in the tidal marsh. This not only damages the vegetation directly, but the large number of geese feeding on the marsh also compact the soil and indirectly damages the habitat. It has been found that geese grazing patterns change the low marsh habitat to intertidal mudflat. The geese have been slowly moving southward and now concentrate in the softer soils of DE (Wetlands Research Associates, Inc., 1995).

4.1.7.2 Temporal and Spatial Trends

During the more than 300 years of development since European settlement, habitat loss has occurred as wetlands and streams were filled, shorelines were altered, and in-water habitats modified. Overall, the collective data suggest that magnitude of loss was significant. Our historical and current ecology report (ARCADIS BBL and Integral, 2007) presented a very detailed analysis of the spatial and temporal trends in wetland loss and shoreline alteration which is summarized briefly below by state and then for tributaries.

4.1.7.2.1 Pennsylvania

The northern section of the Estuary on its western banks is located in lower Bucks County, PA. In the 18th and 19th centuries, this area supported an agricultural landscape with a large number of scattered woodlots as well as roads, rail lines, and a canal corridor. Industrial development has changed the land profile in the 20th century (Berger et al., 1994). The extent of pre-industrial wetlands is not known for this reach, although losses have been documented in recent decades (Sullivan et al., 1991).

Continuing southward from Bristol through Philadelphia to the Walt Whitman Bridge, urbanization and development have been intense. In the 18th and 19th centuries, this stretch of shoreline was already a major anchoring location for both colonial and industrial era shipping. After two and a half centuries of filling the tidal marshes once occupying that land, the shoreline is now elevated and dry, and supports roadways (including Interstate 95) and numerous residential, commercial, and industrial areas (Berger et al., 1994). By the late 19th century, much of the Philadelphia shoreline was already filled and bulkheaded for industry. The intensity of total losses from pre-settlement times to the present day is not known (Sullivan et al., 1991).

Filling and industrial development eliminated natural shorelines and tidal wetlands throughout the PA portion associated with the Estuary (Sullivan et al., 1991; Walton and Patrick, 1973). Shoreline modification and wetland “reclamation” by filling altered much of the coastline. This alteration occurred to its greatest extent near Philadelphia. Of 3,670 wetland acres historically present in the South Philadelphia region, all (including 2,680 acres of high marsh and 990 acres of low marsh) have been eliminated by filling (Tables 4-10 and 4-11). The area of Tinicum Island, which includes the reach of the Estuary downriver from League Island south to the mouth of the Schuylkill River, is also estimated to have lost all of its 1,510 acres of historical wetlands. Of the 1,510 acres, 800 acres of meadow and 500 riverine acres were lost to development. Another 150 acres of meadow were converted to open water, and 60 acres of meadow were filled for highway construction (Tables 4-10 and 4-11).

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A specific historical alteration of note was the filling of a large span of low marsh once present on the Philadelphia shore. In 1887, this marsh was filled as part of construction activities for the Philadelphia Naval Shipyard (now the Naval Business Center). Only small patches of freshwater forested/shrub wetland remain in the area on the current wetland maps. In addition, wetlands up the Schuylkill River and on the north shore have been largely eliminated or substantially altered. Similarly, wetlands in the vicinity of the present Philadelphia International Airport have been filled or impacted by construction for the airport itself, and associated transportation and municipal infrastructure (Sullivan et al., 1991). Throughout the remaining PA and northern DE coastline, filling and development have been significant, with entire stretches of shoreline wetlands disappearing over time.

In recent times, wetland losses in the PA portion of the Estuary have slowed. From 1975 through 1986, about 184 of 1,640 wetland acres were filled and eliminated (Table 4-12; Sullivan et al., 1991).

4.1.7.2.2 Delaware

From the mouth of the Christina River in Wilmington to the Chesapeake and Delaware Canal, the shoreline landscape of much of DE along the Estuary has been altered. During the 19th and early 20th centuries, this region had already been altered by the creation of hundreds of acres of agricultural lands. During that time, recreational beaches lined the shores of the Estuary. Much of the agricultural land is now devoted to suburban housing and industry. Some lowland agricultural areas have returned to tidal marsh (Berger et al., 1994). The tidal marsh that once bordered the mouth of the Christina River is now all but gone and replaced with small patches of open water. The swath of cultivated lands that once existed in Wilmington and New Castle have either been developed or converted to low marsh bordering the river. South of New Castle to the Chesapeake and Delaware Canal, low marsh is still found adjacent to the river.

In the immediate vicinity of the Christina River, all 2,520 acres of historical wetlands have been lost (Wetlands Research Associates, Inc., 1995). Of the 800 acres that were high marsh meadow, 140 were lost to development, 170 were lost to highway construction, and 490 were lost to dredging. Tidal low marsh comprised 1,170 acres, of which 500 were lost to development and 670 were lost to highway construction. The remaining 550 acres of wetlands were dredged (Table 4-10). It is estimated that there were 1,265 wetland acres historically present in the vicinity of Red Lion Creek and the Chesapeake and Delaware Canal. About 70 of those acres have been converted to open water. Much of the remaining acreage, composed of meadow, tidal marsh, and riverine habitat, was lost to dredging (i.e. filling with dredge material) (Table 4-10).

From 1938 to 1973, Sullivan et al. (1991) estimate that 5,730 acres of wetlands in the DE regions of the Estuary were lost to filling and creation of waterfowl impoundments (the installation of dikes and/or gates to obstruct tidal flow for the purpose of creating or enhancing waterfowl habitats) (Table 4-12).

4.1.7.2.3 New Jersey

The eastern banks of the Estuary in NJ also reflect a changing landscape dominated by human activity. Residential, commercial, and industrial development occupies much of the land from Trenton to Palmyra (Berger et al., 1994). From Palmyra through Camden, and Gloucester to the mouth of Big Timber Creek, lies the urban center of the eastern shore of the Estuary. Into the 1950s, significant acreage of woodland and fields remained bordering the various towns, and tributaries remained open and largely unaltered, possibly due to a sluggish regional economy and associated lack of development pressure (Berger et al., 1994).

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Despite less intensive development, substantive wetland alterations and losses occurred in this area. Of particular note are the once-expansive riparian wetland areas surrounding Newton Creek, dividing Camden and Gloucester and Big Timber Creek. Additional wetland acreage was lost in the vicinity of Gloucester around Woodbury and Mantua Creeks. All of the historical 780 wetland acres estimated for this area have been lost. Almost half of the total acreage lost, 365 acres, was tidal marsh. Of that total, 280 acres were lost to development, ten acres were lost to highway construction, and 75 acres were lost to dredging. Another 130 acres of high marsh meadow were lost to development and 55 acres to dredging. The remaining 230 acres of riverine habitat were lost to dredging (Table 4-10). South of Gloucester, the area between Raccoon and Oldmans Creeks once contained an estimated 2,910 acres of wetlands. Of that total, almost all was lost to dredging (Table 4-10).

From the mouth of Big Timber Creek south to the present Delaware Memorial Bridge lies a portion of the NJ coastal plain that was largely converted to agriculture and scattered woodlots in the 1890s. Wetlands remained in many riparian and shoreline areas. Relatively small towns and associated transportation networks (railroads and roadways) were located primarily in the upper reaches of tributary creeks. Today, this land use pattern has changed somewhat, although development is less intense than in other areas of the watershed. Additional acreage is now devoted to industry and residential development, agriculture acreage has declined, and highway infrastructure has expanded (Berger et al., 1994). In the vicinity of Killcohook and Artificial Island, it is estimated that 2,330 acres of wetlands were lost to dredging. However, 590 wetland acres have been created with dredged material on Artificial Island (Tables 4-10 and 4-11).

In general, well over 25% of the historical tidal wetlands were lost on the NJ shore of the Estuary from 1953 to 1972 (Table 4-12; Sullivan et al., 1991). Losses were dominated by conversion to agriculture and filling.

To address wetland loss and in response to its New Jersey Pollutant Discharge Elimination System (NJPDES) permit, PSEG began habitat restoration efforts which initiated the Estuary Enhancement Program. Under the program, more than 20,000 acres of wetlands and adjacent upland buffers are being restored, enhanced, and preserved.4 The wetland restoration program focuses on diked salt hay farms, Phragmites-dominated wetlands, and fish ladders. Salt hay farm restoration parcels comprise about 2,894 acres (plus 339 acres of upland buffer) in Commercial Township (Cumberland County), about 1,135 acres (plus 108 acres of upland buffer) in Maurice River Township (Cumberland County), and 369 acres (plus 15 acres of upland buffer) in Dennis Township (Cape May County). Restoration of Phragmites-degraded wetlands in Salem County and Cumberland County, NJ and New Castle County, DE has successfully converted over 5,000 acres back to productive brackish tidal Spartina marshes. Installation of fish ladders has restored access to around 1,000 acres of fish habitat (PSEG, 2004).

4.1.7.2.4 Tributaries

There are a large number of tributaries to the Estuary and they too have been subjected to intense pressure from urbanization and industrialization. A multitude of tributaries, from large rivers to small creeks, can be seen on historical maps meandering through the watershed and eventually entering the Estuary. Most of the shoreline area along the upper Estuary has been developed. Many of the streams that were present throughout the Estuary have been rerouted, straightened, tunneled into underground sewers, filled, or dammed. A substantial number of the small unnamed creeks have simply disappeared from historical maps. As presented in Table 4-13, 30% of streams that could be seen entering the Estuary on maps created between 1886 and 1927 have 4 The 20,000 acres is inclusive of restoration activities in both New Jersey and Delaware.

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either completely disappeared (based on present day maps) or no longer appear to enter the Delaware River due to filling, damming, redirecting, or rerouting underground.

4.1.7.3 Data / Information Gaps and Uncertainties

Habitat loss throughout the Estuary has been extensively documented. Records of significant habitat loss are readily available and computerized technologies such as satellite imagery allow for fine-scale mapping of current habitat conditions. Comprehensive understanding of the effects of multiple stressors on habitat loss (or conversion to a different type of habitat) is highly complex, such as the interplay between habitat type and the location of the salt wedge, which is itself affected by water removals for human use, drought, dredging, and sea level rise. Additional information on the effects of habitat loss on the structure, function, and inherent health of resident communities of the Estuary is needed. Additionally, more comprehensive information on ecological impacts is needed to better understand the system-wide effects of the loss of natural habitat in the Estuary.

4.2 Chemical Stressors

As described in detail in ARCADIS BBL and Integral (2007), the Estuary is a highly industrialized and developed watershed. As occurs in developed watersheds throughout the nation, chemicals are introduced from a variety of point and non-point discharges within the Estuary. These include municipal and industrial WWTP outfalls, CSOs, storm drains, spills, and other accidental releases, groundwater discharge, and atmospheric deposition.

Surface water outfalls throughout the Estuary are shown in Section 3 (Figures 3-2a–c) as are the facilities that have had documented chemical releases to the environment (Figures 3-3a–c). The broad distribution of different types of surface water dischargers along the Estuary is shown in Figure 4-15.

A variety of chemical stressors can be associated with point sources along the Estuary. For example, industrial discharges may contribute various volatile organic compounds (VOCs,) semivolatile organic compounds (SVOCs), metals, polychlorinated biphenyls (PCBs), dioxins, nutrients, and other chemicals. Sewage treatment plant discharges can include nutrients, PCBs, metals, pharmaceutical and personal care products, along with other chemicals. Oil and coal power plants can discharge polycyclic aromatic hydrocarbons (PAHs), petroleum compounds, VOCs, SVOCs, metals, and nitrogen and sulfur oxides (NOx, SOx). Maritime operations can be associated with release of petroleum and related compounds from commercial vessels into the water, as well as diesel exhaust into the air. Spills of cargo during unloading and loading can also introduce chemicals to the Estuary. Furthermore, chemicals associated with anti-fouling paints previously used primarily on commercial vessels (e.g., TBT) and potentially still used on naval vessels, could be associated with releases from these facilities.

Non-point sources, which exist throughout the Estuary watershed, may also contribute a relatively similar diversity of chemical stressors including pesticides. Important non-point sources in the Estuary include agriculture runoff, CSOs, storm water, and atmospheric deposition.

Once released, chemicals can alter the ecology of the Estuary by affecting growth, reproduction, survival, or any number of physiological or behavioral processes that ultimately influence the ability of member species to effectively compete and perpetuate in the environment. Species that are unable to tolerate the presence of certain chemicals or mixtures of chemicals may be replaced by other more tolerant species, resulting in anywhere from minor to major shifts in community structure, function, and health.

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For a given species, the effects of exposure to a given chemical will depend on the chemical concentration, the route, timing, duration, and magnitude of exposure and the inherent toxicity of the chemical to that species. In this section, we present available data that can be used to characterize chemical sources and resultant concentrations in various exposure media. We focus on data for chemicals present in water, sediment, and biological tissue because these media represent the principal exposure media for the Estuary’s ecological community, although data on chemical levels in the air are presented in situations where atmospheric deposition has been identified as a key source.

As a consequence, the data gathering approach used for chemical stressors focused on identifying large regional data sets that would provide quantitative data synthesized on a regional scale. We acknowledge that a multitude of site-specific chemical data sets are likely available that focus on releases associated with waterfront industries or outfalls. We also recognize that some of that site-specific data may contain higher chemical concentrations than are found in regional data collection programs that may have sampled farther offshore. However, our regional focus is consistent with the goal of the Delaware River Study to assess regional ecological conditions.

Numerous sources of data were drawn upon, including historical summaries of the pollution history and the historical water quality of the Estuary. Several key sources were used to provide a qualitative historical perspective on chemical source, presence, and concentration. Especially important in this regard are the detailed reviews presented by Sutton et al. (1996), Kreeger et al. (2006), Dove and Nyman (1995), and DELEP (1996) as well as information in Najarian Associates, Inc. (1991) and Sharp (1983). In addition, chemical sampling data for the general watershed including the Estuary published by Fischer et al. (2004), Riva-Murray et al. (2003), and Brightbill et al. (2004) were used to provide a general perspective on spatial distribution of chemicals and tributary contributions to the Estuary.

These sources were augmented with more recent data that can be used to provide a quantitative characterization of chemical stressor sources and distribution in the Estuary under current conditions. The references that provide the most recent Estuary-wide monitoring data and information are as follows:

� Hauge (1993). Pesticide concentrations in fish (fillet).

� Costa and Sauer (1994). Chemical concentrations in sediment for 16 sampling stations throughout the Estuary. Chemicals include PCBs, pesticides, and PAHs. DRBC Zones by sampling station are approximated as: stations 1-4: Zone 5; stations 5-9: Zones 4-5; stations 10-16: Zones 2-4.

� Frithsen et al. (1995). Loading estimates of metals, pesticides, PAHs, nutrients, and select volatile organic chemicals from both point and non-point sources.

� DRBC (2006a, 2003a). Estimates of current PCB loadings with EPA-sanctioned total maximum daily load (TMDL) values across Zones 2–6. PCB concentrations in fish (fillets) across all zones over past 20–30 years.

� DRBC (2006b, 2003b, 1998). Analyses of PCB discharges via point and non-point sources.

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� Tetra Tech and Andrew Stoddard Associates, Inc. (2000). Nutrient data summarized by river kilometer for multiple years: 1968–1970, 1978–1980, and 1988–1990.

� Hartwell et al. (2001). Chemical concentrations in sediment for 70+ sampling stations throughout the Estuary. Chemicals include metals, PCBs, dioxin, pesticides, and PAHs. Sampling stations utilized in this effort are shown in Figure 4-16. DRBC Zones by sampling station are the following: Zone 2: stations 1-4, 6; Zone 3: stations 5, 7-14; Zone 4: stations 15-18; Zone 5: stations 19-33, 35-36; Zone 6: stations 34, 37-61.

� Ashley et al. (2004). PCB concentrations across all zones in various fish species (fillet) and invertebrates (whole body).

� Santoro (2004). Nutrient data summarized across the Estuary.

� Reinfelder and Totten (2006). Total mercury concentrations by season across DRBC Zones 2–6, along with volatilization fluxes.

Data from these specific reports were supplemented by examining data from a number of publicly available chemical sampling databases that exist for the Estuary and its tributaries. The particular databases that were accessed are listed in Table 2-2. GIS maps were prepared showing the locations of the sampling stations found in these data sets.5 These maps provide an indication of the density of sampling stations and areas where data have been collected as part of large regional surveys for the Delaware River and its tributaries. Figures 4-17a–c show locations where sediment chemistry data were collected. Figures 4-18a–c contain water column sampling stations that included metals and/or organic chemicals in addition to conventional parameters. Figures 4-19a–c depict sampling stations where samples for tissue chemistry data were collected.

Collectively, the large regional data sets provide comprehensive spatial coverage throughout the Estuary. The number and density of sampling locations varies by medium, however, with the greatest sampling number and density pertaining to water quality samples, followed by sediment samples. Far fewer locations were sampled for tissue data. On a year-by-year basis, the sampling density decreases given that not every point was sampled every year.

Because of potentially significant cross-program differences in study objectives, sampling strategies and methods, analytical methods, target analytes, reporting protocols, and quality control, it is difficult to meaningfully and reliably combine these regional data in a systematic and precise quantitative fashion. Such an effort is beyond the scope of this work and would require extensive levels of planning, outreach, and scrutiny. However, others in the literature have attempted to examine these and other regional data to assess overall contaminant burden in the Estuary. To the greatest extent possible, we have drawn upon these efforts with the balanced recognition of the limitations inherent in such meta-compilations. The following sections present an overview of the characteristics of the regional stressors within the Estuary derived from the collective literature.

4.2.1 Petroleum, PAHs, and Related Compounds

Petroleum is broadly used to refer to products that are derived from oil. Petroleum products fall into three major categories: fuels, such as motor gasoline and distillate fuel oil (diesel fuel); 5 This effort was conducted only for those databases that provided sampling coordinates in latitude and longitude. We did not attempt to approximate coordinates if the database provided location using another type of location data (e.g., river mile).

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finished nonfuel products, such as solvents and lubricating oils; and supply products for the petrochemical industry, such as naphtha and various refinery gases (USDOE, 2005).

A variety of chemicals are constituents of petroleum. Petroleum is principally made up of hydrocarbons and hence the term petroleum and hydrocarbons are often used interchangeably. PAHs are an environmentally persistent component of petroleum. (Though PAHs also emanate from combustion of fossil fuel and other sources, they are discussed in this section given their presence in petroleum.) Other petroleum constituents include VOCs frequently found in refined petroleum products (e.g., gasoline), such as benzene, toluene, and the additive methyl tert-butyl ether (MTBE). Because of their characteristics, VOCs, such as benzene and toluene, are not persistent in the surface water environment, whereas denser VOCs, such as MTBE, can persist (Fischer et al., 2004; Sutton et al., 1996). Other petroleum constituents include the minor elements nitrogen, sulfur, and oxygen. Trace metals such as nickel and chromium (discussed in a later section) are also components of some crude oils.

4.2.1.1 Sources

The Estuary is the home of the third largest oil port in the U.S. There are six major oil refineries along the shores of the Estuary that handle approximately 70% of the oil imports on the East Coast of the U.S. In total, there are 17 total petroleum bulk terminals and general petroleum facilities present on the shorelines of the Estuary (USEPA, 2006a).

A major point source of petroleum and related compounds in the Estuary has been accidental oil spills (Figure 4-20). Since 1972, 12 documented oil spills have occurred in the Estuary, with the most recent spill occurring on November 26, 2004, when the Athos I dumped 265,000 gallons of heavy crude oil near Philadelphia (Corbett, 2004). The largest documented spill was approximately 11,000,000 gallons of crude oil dumped in 1975 by the Corinthos near Marcus Hook, PA (Corbett, 2004). Following most oil spills, the majority of lingering oil on the water or sediment surface volatilizes relatively quickly or is otherwise degraded as a result of chemical and physical weathering processes. Even surface oil that ultimately reaches subsurface sediments is prone to physical and chemical weathering, thereby minimizing the long-term toxicity of sporadic oil spills. Certain forms of weathered oil (e.g., tar, asphalt) can persist following spills, but bioavailability of toxic constituents in these forms is typically very low. PAHs that have been released and sorbed to sediments can persist and remain bioavailable for long periods of time, although almost always at concentrations and composition substantially different from immediate post-spill conditions (Short et al., 2004; Page et al., 2002; Hayes and Michel, 1999).

Other point sources of petroleum and related compounds include fuel spills from recreational and commercial watercraft, as well as industrial effluents along the shoreline of the Estuary. Petrogenic sources from such industries as oil refineries (Alden et al., 2005; Hall et al., 2005) are additional point sources of petroleum compounds to the Estuary and PAHs are often found to be major components of those discharges.

Non-point sources of petroleum and related hydrocarbons include atmospheric deposition (e.g., from fossil fuel combustion) and urban runoff. Frithsen et al. (1995) estimated that approximately 35,000 kg of PAHs enter the Estuary annually via urban runoff and atmospheric deposition. Costa and Sauer (1994) further characterized PAHs found in sediments of the Estuary as being derived primarily from fossil fuel combustion (i.e., pyrogenic origin).

Frithsen et al. (1995) estimated that 95% of the approximately 35,000 kg of annual non-point source loadings of PAHs to the Estuary originated from urban runoff. However, the authors did

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not have sufficient data to assess point source introductions. Although Costa and Sauer (1994) suggested that most of the PAHs adsorbed to sediments in the Estuary originated from fossil fuel combustion (via atmospheric deposition), the study also recognized that petroleum-related compounds from direct inputs of petroleum (e.g., oil spills) may also be an important source. The importance of non-point sources to the input of PAHs to the Estuary is also supported by Sutton et al. (1996). Based on this limited literature, it appears that non-point sources most greatly contribute PAHs to the Estuary, although the role of direct sources is also recognized to be potentially important.

Primary point sources of PAHs, petroleum, and related compounds include fuel releases and industrial effluents, whereas the primary non-point sources are urban runoff and atmospheric deposition.

4.2.1.2 Metrics

Chemical concentration is the metric by which the magnitude of PAHs, petroleum, and related compounds are gauged. Concentrations of associated compounds in environmental media provide an integrated measure of loadings to a system across all sources. Because of varying chemical properties, some petroleum-related compounds such as PAHs are more persistent in the environment, compared to more volatile compounds such as benzene and toluene. Because individual PAHs have a wide range of molecular weights, their persistence in the environment varies. However, concentrations in various media can be used to help define spatial and temporal trends.

Although the supporting data are limited, it appears that PAHs are not present in fish tissue in the upper Estuary. This finding is consistent with the fact that fish metabolize PAHs efficiently via a liver oxidative enzyme pathway. As shown in Pinkney et al. (2001), biomarkers of PAHs can provide an integrated measure of exposure in fish, and indirectly a measure of stressor strength. PAHs have been detected in bivalves (Sutton et al., 1996; Gottholm et al., 1994), which do not metabolize PAHs; however, the reported concentrations are relatively low. Overall, food web contamination by PAHs does not appear to be a significant phenomenon in the Estuary. Given this, as well as a limited amount of bivalve data, information on tissue concentrations is not presented in this report. The subsequent discussions focus on concentrations specifically in sediment and water.

4.2.1.3 Temporal and Spatial Trends

The discussion of temporal and spatial trends is organized by environmental medium. The trend data for sediment focus on PAHs because these environmentally persistent compounds preferentially partition to sediment. The trend data for water focus on the volatile and more soluble petroleum fractions, which are more likely to be found in water. Concentration data discussed below are reported on a dry weight basis in sediment and a total basis in water, unless otherwise noted.

4.2.1.3.1 Sediment

PAHs have been detected in sediments throughout the Estuary. Costa and Sauer (1994) detected PAHs (including alkylated PAHs) at 16 stations distributed across all zones of the Estuary, with the highest total PAH concentrations detected at stations offshore from Philadelphia, where a maximum concentration of approximately 41 mg/kg (ppm) was found (Figure 4-21). The most common individual PAH compounds detected in the sediment samples were benzo(a)pyrene, benzo(b)fluoranthene, fluoranthene, phenanthrene, and pyrene (Santoro, 1998; Costa and Sauer, 1994).

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The USGS National Water Quality Assessment (NAWQA) Program evaluated sediment concentrations of PAHs throughout the Delaware River Basin (Fischer et al., 2004). This comprehensive study included sampling stations distributed throughout the Basin ranging from the Appalachian Plateau in New York State to the actual Estuary. Though sampling data specific to the Estuary are not presented separately in this report, the regional data do indicate that PAHs are widely distributed throughout the watershed. PAHs were detected in sediment samples collected in all land-use types—forested, urban, and agricultural settings—as well as the main-stem of the Delaware River. Concentrations of total PAHs at all urban sites exceeded a commonly cited screening-level sediment toxicity guideline value referred to as a threshold effects concentration (TEC)6 (Fischer et al., 2004). The TEC was exceeded most frequently at urban sites and in the main-stem of the River, consistent with expectation that runoff from urban areas is a significant source of PAH loading. The probable effects concentration (PEC)7 was exceeded at 46% of urban sites, but only 17% of forested sites. The median concentration of total PAH at urban sites and in the main-stem of the River was approximately 10 mg/kg and exceeded the TEC (Fischer et al., 2004), whereas the median concentrations at the agricultural and forested sites were less than the TEC.

More targeted on the Estuary, Hartwell et al. (2001) evaluated concentrations of low molecular weight PAHs (LPAH) and high molecular weight PAHs (HPAH) throughout the Estuary as part of the NOAA NS&T Program. LPAHs and HPAHs (including alkylated homologues) were similarly represented across all stations, with highest concentrations observed in the industrialized areas of Zones 2 and 3 (Figure 4-22). The highest total PAH concentration was observed at Station 13 (Zone 3) near south Philadelphia, with a reported concentration in excess of 18 ppm (dry weight). Station 17 (Zone 4), south of Philadelphia, actually had a reported concentration > 157 ppm, but this was determined to be a spurious sample because its location was in a ship turning basin in a heavily industrialized section of the Estuary (Hartwell et al., 2001). Figures 4-23 and 4-24 differentiate between the base and alkyl-substituted PAHs within both LPAHs and HPAHs, respectively. The relatively greater presence of alkyl-substituted PAHs in the LPAHs implies a mixture of pyrogenic and fuel-spill sources, whereas the HPAHs are believed to have originated from pyrogenic sources such as fossil fuel combustion (Hartwell et al., 2001).

Additional sampling conducted by Black and Veatch Waste Science, Inc. (1996) throughout the Delaware River’s industrialized corridor (Philadelphia to Chester/Wilmington) showed relatively high PAH concentrations along the shoreline adjacent to shipyards and petroleum facilities, with maximum individual PAH concentrations ranging from approximately 0.6 ppm (chrysene, anthracene) to approximately 2 ppm (pyrene).

Collectively, the available sampling data indicate that PAHs are ubiquitous in the Estuary and its watershed, with the highest concentrations present in industrialized and urban areas. Localized spikes in concentrations can occur adjacent to particular sources, such as shipyards and petroleum facilities. Too few data are available to assess long-term trends in sediment.

4.2.1.3.2 Water

Volatile organic constituents of petroleum were observed in streams and groundwater in the Delaware River Basin during sampling conducted as part of the USGS NAWQA Program (Fischer et al., 2004). Gasoline products (including benzene and toluene) were observed more frequently in surface water, whereas less degradable compounds, such as MTBE, were observed 6 A TEC is defined as the chemical concentration below which toxic effects are not expected to occur. 7 A PEC is defined as the chemical concentration above which toxic effects are expected to occur.

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in groundwater as well (Figure 4-25). The concentrations of VOCs were relatively low, with only MTBE exceeding one part per billion (ppb) in surface water (Fischer et al., 2004). The number of compounds detected was greatest in urban areas likely due to greater use and production of gasoline products, solvents, and sewage in those areas. In contrast, DRBC did not detect any volatile compounds in Estuary surface water during a 1997 survey, at a detection limit of 1–2 ppb (Santoro, 1998).

Fischer et al. (2004) observed a seasonal trend in which most solvents and gasoline compounds were detected in surface water during the winter, most likely because of the higher rates of volatilization during the warmer summer months. However, the Schuylkill River in Philadelphia and the Delaware River near Trenton showed summer peaks in MTBE, mostly likely because this denser compound was released during increased use of motorized watercraft (Fischer et al., 2004).

4.2.1.4 Data / Information Gaps and Uncertainties

Overall, the available sediment monitoring data are sufficient to characterize the general Estuary-wide presence of PAHs, with surface runoff and atmospheric deposition being the predominant source. Several studies documented the ubiquitous distribution of PAHs and their higher concentrations near industrial and urban sources. This is consistent with general expectation given the source along with the fate and transport characteristics of these compounds. The data compiled by Hartwell et al. (2001) are sufficient to provide a quantitative characterization of conditions throughout the Estuary, but these data are over one decade old. Further, the sampling density and distribution were not sufficient to understand PAH distribution relative to likely or known sources. It was beyond the scope of this report to compile monitoring datasets of sediment chemistry. Such a summary, however, would better provide an updated and comprehensive understanding of PAH contamination throughout the Estuary.

Too few data are available to reliably assess the presence and concentrations of volatile petroleum fractions in the Estuary. The two data sources from which surface water data were available presented contradictory information. Nevertheless, surface water contamination by volatile fractions is not expected to be an important stressor throughout the Estuary simply because these compounds are indeed volatile and are not expected to persist in the water column. It is possible, and even likely, that these volatile fractions will be present in surface waters located adjacent to continuous sources, such as a contaminated aquifer. However, there is no indication that these types of local VOC sources are spatially pervasive throughout the Estuary, and therefore, this type of source will likely operate on a local, not regional, scale.

There is a general lack of tissue data for PAHs, but this is not considered a significant data gap because: 1), PAHs are metabolized and do not bioaccumulate in fish and, 2), the levels measured in bivalves (which do not metabolize PAHs) are low.

Importantly, however, the overall magnitude of oil-related stressors cannot be evaluated solely on the basis of constituent chemicals present in environmental media. Irrespective of long-term persistence, oil released during an oil spill can have significant ecological impact on resident species if sufficiently large (e.g., the Exxon Valdez oil spill in Alaska) or if they occur during an especially sensitive time during a species’ life cycle. For example, the Estuary is an important resting and feeding ground for migratory shorebirds, which stop in the Estuary to feed on horseshoe crab eggs found in the sandy beaches of the Bay. These birds enter the Estuary to feed in large numbers that, in some cases, represent a significant proportion of the total population of

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the species. Thus, oil spills also pose a risk to shorebird populations, particularly if a spill were to occur during critical breeding/migration periods (Clark and Gelvin-Innvaer, 1995).

4.2.2 PCBs

PCBs are a class of compounds that were manufactured for various uses, most notably as dielectric fluids in transformers and capacitors. PCBs were manufactured in the U.S. by Monsanto Corporation under the trade name Aroclor®. Aroclor products, which contain a number of different PCB compounds, include Aroclors 1221, 1232, 1016, 1242, 1248, 1254, 1260, 1262, and 1268. For all Aroclors except Aroclor 1016, the last two numbers indicate the overall level of chlorination of the PCBs. For example, Aroclor 1248 contains 48% chlorine by weight.

There are 209 different PCB compounds, or congeners, containing from one to ten chlorine atoms in various configurations. Each group of congeners with a given number of chlorines is categorized as a homolog group (e.g., the homolog group pentachlorobiphenyls consists of PCB congeners with five chlorine atoms). In general, environmental persistence increases along with the degree of chlorination.

Several different laboratory methods are available for PCB analysis, and the nature of the information provided varies by method. A commonly used method is gas chromatography with electron capture detection (e.g., USEPA Method 8082), which is generally used to analyze samples for PCBs as Aroclors, but can also be used to analyze samples for individual PCB congeners. Gas chromatography with mass spectrometry (e.g., draft USEPA Method 1668) is most commonly used to analyze samples for PCB congeners. Analysis may be completed for the entire suite of 209 congeners or for a subset, consisting of only the coplanar congeners, which are considered the most toxic. “Total PCBs” can be derived in many different ways depending on which method is used by the laboratory. For example, total PCBs can be reported based on the sum of the results for all Aroclor groups and/or the sum of all 209 PCB congeners. The sum of all toxic dioxin-like congeners is often affiliated with PCB analyses by laboratories as well.

The monitoring data reported for the Estuary are based on a variety of analytical methods. Consequently, the analytes reported vary by study. In addition, the precise interpretation of the meaning of total PCBs cannot be known unless the particular method for calculating the total is specified in the report or data set. In this section, we present sampling data as reported by the authors. We did not review analytical methods used to determine the compatibility of data generated in different studies.

4.2.2.1 Sources

PCBs have been documented in the Estuary since the 1960s when they were first detected in fish tissue (DRBC, 2003a; Riva-Murray et al., 2003). A variety of point sources has been identified for PCBs including abandoned waste sites (e.g., Brownfield and Superfund sites), WWTPs, and industrial discharges. Non-point sources include storm water outfalls, CSOs, contaminated site runoff, and atmospheric deposition. In addition, PCBs present in river sediments act as a continuing non-point source. Because of these point and non-point sources, PCBs have been listed as a cause of impairment throughout Zones 2–5 of the Estuary, as detailed in Table 4-14, as well as in Zone 6. The relative strengths of these diverse sources have been examined in the context of the development of the USEPA Regions 2 and 3 PCB TMDL by DRBC in 2003 (DRBC, 2003a) and 2006 (DRBC, 2006a).

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4.2.2.1.1 PCB TMDL Development

In the 1990s, DE, PA, and NJ collectively designated portions of the Estuary (Zones 2–5) as an impaired water body under Section 303(d) of the CWA, primarily due to high PCB levels in fish. Total PCB water quality standards adapted from DRBC in 1996 were used to form the basis for TMDLs. These standards are 44.4 picograms per liter (pg/L) for Zones 2 and 3, 44.8 pg/L for Zone 4 and the upper portion of Zone 5, 7.9 pg/L for the lower portion of Zone 5, and 64 pg/L for Zone 6 (DRBC, 2006a, 2003a). The discrepancy in PCB standards between the lower portion of Zone 5 and the remaining zones is due to a higher fish consumption rate used by DRBC for the lower Estuary (lower Zone 5).TMDL development was divided into two stages to accommodate the need for additional data collection and modeling. DRBC (2006a, 2003a) describes the TMDL development process for the Stage I TMDLs based on penta-PCB homologues. This focus is the result of DRBC’s (2003a) determination that penta-PCB homologues represent the majority of PCB constituents in the Estuary. The resulting TMDLs (mg/day) are as follows: Zone 2—257.4, Zone 3—17.8, Zone 4—56.7, and Zone 5—48.1 for a total of 380.0 mg/day (DRBC, 2003a). The Stage I PCB TMDLs are 2–3 orders of magnitude below currently understood PCB loadings, particularly in heavily industrialized areas (DRBC, 2003a). Figure 4-26 compares TMDL loadings with existing loading values for penta-PCB congeners in the Delaware River at Trenton, the Schuylkill River, and DRBC Zones 2–5 (DRBC, 2003a). The Zone 6 TMDL was released in September, 2006 as 1876.5 mg/day (DRBC, 2006a). This value is built upon the TMDLs developed for Zones 2-5 in 2003. It reflects > 80% of total TMDLs for all Estuary Zones due to a high load allocation from the relatively large influence of the ocean on pollutant concentration in the Bay. The Zone 6 TMDL is not a result of discharges regulated under NPDES. Even so, this load allocation is equivalent to only 14.5 pg/L of Total PCBs, which is well below the Zone 6 and ocean water quality criterion of 64 pg/L (DRBC, 2006a).

Stage II PCB TMDL work, based on additional data collection, advanced modeling and all PCB homologues, is scheduled to be completed in December 2008 (DRBC et al., 2006). Until Stage II is completed, TMDL results presented in 2003 and 2006 (Stage I) represent the final and effective TMDLs supporting the CWA.

4.2.2.1.2 Source Types and Loadings

Loadings of PCBs to the Estuary were first investigated by DRBC in 1996 and 1997 (DRBC, 1998). This study examined mass loadings of PCBs during wet and dry conditions, with an emphasis on municipal/industrial wastewater point discharges and tributaries, to assess relative contributions to the Estuary. CSOs were also assessed during wet weather. Table 4-15 summarizes regional PCB loadings by DRBC zone as originally estimated by DRBC (1998). Point sources were shown to dominate PCB inputs during dry conditions, with total loadings to the Estuary estimated at 34.25 g/day. Under wet weather conditions, however, tributaries contributed a substantially greater loading to the Estuary, increasing to nearly 84 g/day up from <2 g/day under dry conditions. Total wet weather loadings from point sources and tributaries were dwarfed, however, by the loadings from CSOs, estimated to contribute >2,000 g/day during wet weather. This discrepancy in loadings between wet and dry weather is particularly evident in Zone 3 as a result of CSO contributions, with estimated mass loadings nearly 70 times greater during wet weather than during dry weather (Table 4-15).

In support of the 2003 PCB TMDL development, daily PCB loads from point and non-point sources were estimated for Zones 2–6 across a 577 day simulation from 2001 to 2003 (DRBC, 2003b). Specific sources examined include contaminated sites, atmospheric deposition, tributaries, CSOs, and a “Boundary” category referring to the Delaware River at Trenton and the

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Schuylkill River. A re-calibrated simulation was released in September, 2006 to account for a previous overestimation of input from contaminated sites in 2003 (DRBC, 2006b). Figure 4-27 shows an updated summary of the 577 day total loads for each source category. Non-point sources contributed 9.22 kg, miscellaneous point sources contributed 6.56 kg, revised contaminated site input was estimated as 3.90 kg, atmospheric deposition contributed 2.34 kg, and CSOs contributed 2.19 kg (DRBC, 2006b). The Delaware and Schuylkill Rivers also contributed 5.26 and 4.00 kg of penta-PCBs, respectively (DRBC, 2006b).

PCB concentrations in specific tributaries have also been assessed by DRBC (1998) with wet weather concentrations significantly higher than dry weather, particularly at Christina and Red Clay creeks (Figure 4-28). PCB concentrations in the main-stem of the River are lower during high flow events (wet weather) and higher during low flow events (dry weather) (Santoro, 2004). This may be the result of greater dilution of water column concentrations during wet weather events.

Atmospheric deposition of PCBs and consequential adsorption by sediments is another means of introduction into the Estuary, and was included in the model for TMDL development (DRBC, 2006a, b, 2003a, b). The two means of atmospheric transfer included in the TMDL model were atmospheric dry deposition and gas phase transfer of PCBs. Gas phase concentrations varied substantially between sample locations (up to two orders of magnitude), and though atmospheric deposition accounts for only an estimated 5% of total PCB loadings, this amount can exceed TMDL values by an order of magnitude (Totten et al., personal communication – 2005 SETAC Annual Meeting).

4.2.2.1.3 Relative Source Strength

Point sources were originally estimated to contribute approximately two-thirds of the PCB loadings into the Estuary (Table 4-16; Frithsen et al., 1995 as presented in Sutton et al., 1996). DRBC (1998) further estimated that approximately 90% of total PCB loadings during wet weather originate from CSOs, with 4–9% coming from tributaries, and the remaining 1–3% originating from other point sources, thus implying even greater disparity between point and non-point contributions. Point sources were also estimated to contribute approximately 95% of PCB loadings during dry weather, with the remainder coming from tributaries.

With the adjustment of contaminated site loading estimates for the more recent 577 day penta-PCB loading simulation, point sources (including fluvial input from the Delaware and Schuylkill Rivers) were shown to dominate total loads for Zones 2-5 (DRBC, 2006b, 2003b). Only Zone 6 had noticeably higher non-point source PCB loading. Regardless of weather conditions or point versus non-point introductions, the majority of PCB loadings enter the more industrialized River zones (Zones 2–5) (DRBC, 2003b, 1998). DRBC (1998) further concluded that rain events significantly increase PCB loadings into the Estuary. This was suggested to occur through increased resuspension of contaminated sediment, erosion, and transport of upland contaminated soil, and PCBs released from sewage collection systems (DRBC, 1998). Overall, both historically and currently, PCB introduction is greatest in urban areas versus rural, particularly from loadings adjacent to Philadelphia.

To supplement PCB TMDL development, DRBC performed waste load allocation estimates for municipal separate storm sewer systems (termed MS4s) likely to discharge to the main-stem of the river, which includes storm drains and reflects non-point sources. Percent of runoff attributable to MS4s was determined as 42% for Zone 2, 88% for Zone 3, 41% for Zone 4, and 29% for Zone 5 under wet weather conditions (DRBC, 2003a). Percent of the total PCB TMDL attributable to MS4s for Zone 6 was estimated as < 1% (DRBC, 2006a).

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4.2.2.2 Metrics

PCB concentrations in environmental media provide an integrated measure of PCB loading to the system across all sources. Because PCBs are hydrophobic compounds, which preferentially partition to sediment and accumulate in biota, these media can be used to help define spatial and temporal trends. PCB concentrations in water are more difficult to measure reliably and provide a less reliable metric by which to assess PCB spatial and temporal trends.

PCB concentrations discussed below are reported on a dry weight basis in sediment and a fresh weight basis in biological tissue, unless otherwise noted.

4.2.2.3 Temporal and Spatial Trends

The discussion of temporal and spatial trends is organized by environmental medium.

4.2.2.3.1 Sediment

PCB distribution in sediments tends to be highest in the urban area near Philadelphia (Zone 3) and decreases downriver (Hartwell et al., 2001; Figure 4-29). It is also higher in nearshore areas than in the shipping channel (Costa and Sauer, 1994). Maximum concentrations over the 73 stations sampled by Hartwell et al. (2001) occurred near the mouth of the Schuylkill River south of Philadelphia (Zone 3). Surface samples collected across all stations were collected to a depth of 3 cm. A maximum total PCB concentration of 295 µg/kg was found at Site Number 13 (Zone 3), located south of Philadelphia in a heavily industrialized area in a marina near Darby Creek. Hartwell et al. (2001) concluded that PCB contamination is prevalent in the upper estuarine zone, not the main bay, and concentrations are greater in the nearshore areas than in the shipping channel. This sediment distribution does not include planar-PCBs as Hartwell et al. (2001) did not analyze these chemicals at every sampling station.

Costa and Sauer (1994) consistently found the highest concentrations of PCBs occurring between Trenton (Zone 2) and Chester, PA (northern Zone 4, south of Philadelphia) in surface sediment samples (composite samples collected to a depth of 2 cm). Maximum concentrations reported by Costa and Sauer (1994) were consistent with those found by Hartwell et al. (2001) and ranged from 97 µg/kg north of the Delaware Bay to 280 µg/kg near Philadelphia.

PCBs were also observed in the shipping channel during a USACE sediment testing program that supported the Delaware River deepening project (Burton, 1997). Maximum concentrations of total PCBs observed in these shipping channel sediments were 74.7 µg/kg in surface sediments (defined as 0–3 in. in the sediment column) and 152 µg/kg between 3 and 5 in. below the water–sediment interface (Burton, 1997). More elevated concentrations in subsurface sediments indicate higher loadings historically and a reduction in the discharge of PCBs over time. Costa and Sauer (1994) conducted a study of nearshore shoal areas in the same areas of the Estuary and found total PCB concentrations substantially greater than those reported by Burton (1997) for the shipping channel. Data from both studies were categorized into nearly identical “reaches” and the studies used the same high resolution methods, so direct comparisons of concentrations are possible (Burton, 1997). Concentrations in nearshore surface samples near Philadelphia were more than eight times greater than those in nearby channel sediments (177.8 versus 21.9 µg/kg) (Burton, 1997; Costa and Sauer, 1994). Summaries from both Costa and Sauer (1994) and Burton (1997) are also presented in Fikslin and Santoro (2003).

Temporal trends in sediment are more difficult to discern because long-term monitoring at co-located stations has not been conducted. Burton’s (1997) analysis of sediment cores collected in

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the Estuary included surface (0–3 in.) and subsurface (3–5 in.) samples, thus allowing some level of evaluation of temporal trends, although we do not know sediment deposition rates or the years that are represented by these sediment horizons. Figure 4-30 shows total PCB concentrations for both strata from this data set. Concentrations were generally higher in the surface horizon than in the subsurface horizon, except for Station 4 (Philadelphia area) where the total PCB concentration was significantly higher in the sub-surface layer. In light of the definitive difference between surface and sub-surface PCB concentrations at Station 4, Burton’s data imply reduced PCB loadings in more recent years. Reinfelder and Totten (2006) present PCBs (and DDT and mercury) in sediment cores collected at Woodbury Creek in southwest NJ (northern Zone 4) between the 1940s and 2000 (Figure 4-31). PCB concentrations increased rapidly in the 1960s followed by decreasing concentrations beginning in the 1970s, which corresponds to the approximate time that PCB production was halted in the U.S.

4.2.2.3.2 Water

The DRBC’s Boat Run Program is an ongoing monitoring program that began in the 1960s, involving monthly water quality sampling for some parameters from Trenton to the Delaware Bay. Santoro (2004) used the DRBC Boat Run data for several time periods between 2001 and 2003 to examine the relationship between flow and water column total PCB concentrations. He found that PCB water column concentrations are higher during low flow conditions. During low flow sampling events the concentration of PCBs shows a pattern of elevated PCBs between River Miles 80 and 107 (Zones 3 and 4), indicating PCB loadings in the urbanized areas of the river (Santoro, 2004). In higher flow sampling events, concentrations were found to be lower and more evenly distributed throughout the sample area, probably because of dilution of PCBs during high flow conditions.

4.2.2.3.3 Tissue

Fish consumption advisories for the Delaware River have been in existence since the late 1980s as a result of PCB concentrations in fish tissue. Though few fish contain PCBs at concentrations near the U.S. Food and Drug Administration (FDA) action level of 2.0 mg/kg in fillet tissue (Riva-Murray et al., 2003), various states have instituted consumption advisories because of concerns regarding human health risks associated with PCB ingestion. Fish consumption advisories based on PCBs currently range from non-consumption recommendations for all species between the Chesapeake and Delaware Canal to the DE-PA border to consumption of no more than one meal per month of striped bass or white perch from Zones 2–4 (DRBC, 2003a).

Ashley et al. (2004) collected tissue samples (i.e., channel catfish, white perch, prey fish, and invertebrates) in Zones 2 through 5 and analyzed them for PCB congeners. Fish were collected from single locations within each zone. Concentrations were measured in whole body and fillet for fish (with whole body results discussed here8) and whole body for invertebrates. Channel catfish9 had the highest mean PCB concentrations in Zones 3 and 4 over both spring and fall sampling periods with a maximum average concentration of 21,740 µg/kg (ng/g; lipid-normalized) (Figure 4-32a–b). In contrast, maximum concentrations in white perch were reported for fish taken from Zone 4 in the fall (19,776 µg/kg lipid-normalized) and Zone 5 in the spring (26,479 µg/kg lipid-normalized). Prey fish (juvenile species, small fish) had highest PCB concentrations in Zone 3 (33,492 µg/kg lipid-normalized, spring) and invertebrates (amphipods,

8 Whole body concentrations are considered most representative of ecological conditions and potential exposures, as opposed to fillet concentrations, which are considered most representative of conditions appropriate for evaluations of human health. 9 Channel catfish reportedly has a small home range and may be more indicative of localized conditions than other fish species.

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crayfish, grass shrimp, blue crab) displayed considerable variability in PCB concentrations, particularly in Zones 3 and 4 (maximum average concentration 26,001 µg/kg lipid-normalized in Zone 3, fall).

The distribution of PCB homologue groups was also reported by Ashley et al. (2004) and provides a different mechanism for understanding the distribution of sources of PCBs to the Estuary. For example, Figure 4-33 shows the fractional contribution of each PCB homologue group by zone for catfish. For some homologue groups, clear differences between zones occur in the fractional contribution of that homologue group to the total, suggesting different sources. Some attention has been given to the occurrence of congener 209 in the Estuary, and particularly in Zone 5. As shown in Figure 4-34, the concentration of PCB-209 in channel catfish and white perch is generally greatest in Zones 4 and 5.

PCB concentrations in fish appear to have declined through time. DRBC (2003a) has presented overall decreasing trends in PCB concentrations in fillet samples of channel catfish from Zones 2 through 5 (Figure 4-35) for 1977 through 2001, as well as a notable decrease in concentrations of PCBs in white perch fillet samples from Zones 2 through 6 (Figure 4-36) for 1969 through 2002. Mean observed fillet concentrations across all zones for channel catfish have decreased from approximately 1.9 mg/kg in 1985 to approximately 1.0 mg/kg in 2001, and white perch concentrations have decreased from approximately 5 mg/kg in 1969 to approximately 1.0 mg/kg in 2001 (DRBC, 2003a). These levels are still two to three orders of magnitude above the concentrations from which water quality standards have been developed. Riva-Murray et al. (2003) has similarly presented decreasing trends from 1969 to 1998 for American eel, carp, channel catfish, and white sucker (all benthic species) around Trenton (Zone 2) (Figure 4-37). Figure 4-36 further shows that the majority of recent benthic fish samples are below the FDA tolerance level and a wildlife protection value developed by the National Academy of Sciences and National Academy of Engineering (NAS/NAE, 1973 as cited in Riva-Murray et al., 2003).

4.2.2.4 Data Gaps / Information and Uncertainties

There is a relative abundance of data for PCBs compared with other contaminants in the Estuary, and overall, there are sufficient data with which to approximate the general magnitude and distribution of PCBs. The collective data on PCB concentrations in sediment provide solid perspective on spatial trends across the Estuary as a whole (highest in urban areas) and laterally within any given reach (highest nearshore).

The data compiled by Hartwell et al. (2001) are sufficient to provide a quantitative characterization of PCB levels in sediments throughout the Estuary, though not of localized conditions near individual sources. These data are nearly a decade old, so the degree to which they represent current conditions in the Estuary is not known.

The available fish and other biota tissue are sufficient to provide a general perspective on PCB bioaccumulation in the aquatic food web, the general magnitude of concentrations, and spatial patterns. However, whole body concentrations presented in Ashley et al. (2004) and various state data sets, which are more ecologically relevant than fillet concentrations, are insufficient to support a comprehensive assessment. Also, the generally limited data available for top predatory fish in the Estuary is not wholly sufficient to quantify specific degrees of biomagnification that is currently occurring in the aquatic food web. Sampling variability for some species (both fish and invertebrates) may also introduce some uncertainty to interpretation of the data. Finally, the focus of the available tissue sampling to a single location within each zone, limits the degree to which these data can be extrapolated to other parts of the zone.

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Overall, there are too few data available to assess temporal trends, although loading estimates and concentration data in sediments and fish suggest that concentrations are decreasing.

4.2.3 Dioxins and Furans

Similar to PCBs, dioxins and furans are a group of chemical compounds that share certain chemical structures and biological characteristics. Several hundred of these compounds exist and are members of three closely related families: the chlorinated dibenzo-p-dioxins (CDDs), chlorinated dibenzofurans (CDFs), and certain PCBs (discussed in the previous section). Sometimes the term “dioxin” is also used to refer to the most studied and one of the most toxic dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

Dioxins and furans are not created intentionally, but are produced inadvertently by a number of human activities. Natural processes also produce CDDs and CDFs. Dioxins are formed as a result of combustion processes such as commercial or municipal waste incineration and from burning fuels (like wood, coal, or oil).

Few data exist for dioxins and furans in the Delaware Estuary. Hartwell et al. (2001) analyzed dioxins and furans at four locations adjacent to the Philadelphia-Camden metropolitan area and the Chesapeake and Delaware Canal. Stations 10 and 11 (both Zone 3), adjacent to Philadelphia, had relatively low concentrations as compared to Stations 20 (Zone 5, Cherry Island Flats) and 29 (Zone 5, Salem Cove within Ready Island). Though total dioxin and furan concentrations were detected in the estuarine stations, most were in the form of octachlorinated dibenzo-p-dioxin (OCDD). OCDD is substantially less toxic than tetrachlorinated CDD congeners. OCDD resulted in the highest average concentrations (4–5 ng/kg, dry weight) at Stations 20 and 29; furans were highest at Station 29 (5,663.8 ng/kg, dry weight) (Hartwell et al., 2001).

The Dioxin TMDL for the main-stem of the Delaware Estuary is targeted for 2011. Dioxin TMDLs for portions of the Delaware River watershed (i.e., main-stem of Red Clay Creek and Upper Brandywine Creek) are targeted for completion by 2009 and 2011, respectively. These creeks both discharge to Zone 5 (Delaware DNREC, 2004).

Insufficient data are currently available to assess the presence, magnitude, and distribution of dioxins and furans in the Estuary.

4.2.4 Pesticides

Pesticides have been identified as toxic pollutants of concern by DELEP, particularly the chlorinated pesticides DDx (i.e., DDT, and its chief metabolites DDD and DDE), dieldrin, and chlordane (Sutton et al., 1996). Other chlorinated pesticides present in various media throughout the Estuary include aldrin, hexachlorocyclohexane (HCH), endosulfan, endrin, heptachlor, hexachlorobenzene (HCB), mirex, pentachlorophenol, and toxaphene. Chlordane is a cause of fish consumption advisories in Zone 5, based on tissue concentrations that exceeded the FDA action level of 0.3 mg/kg (DRBC, 2004). In addition, Gottholm et al. (1994) concluded that chlordane is widely present throughout the Estuary at some of the highest concentrations observed in the U.S. Concentrations of DDx are also elevated in portions of the Estuary, compared to other parts of the U.S. For example, maximum observed concentrations in oysters from Zone 5 ranked in the top 14th percentile nationally, with a maximum mean value of 202 µg/kg (dry weight) observed at Ben Davis Point Shoal (Gottholm et al., 1994).

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4.2.4.1 Sources

Both point and non-point sources contribute to chlorinated pesticide loadings in the Estuary, and these pesticides have been routinely detected in sediment, water, and tissue. Because of the hydrophobic and lipophilic nature of chlorinated pesticides, they often are persistent in the environment, adhering to sediment particles or accumulating in the fatty tissue of organisms. Much like PCBs, many chlorinated pesticides were manufactured and released to the environment for a relatively short time period prior to being banned by the federal government. The substantial and widespread historical use of these pesticides in agricultural applications, combined with their tendency to bioaccumulate in organisms, has led to their presence and persistence throughout the Estuary.

Few data are available that quantitatively estimate pesticide source type and strength. Frithsen et al. (1995) estimated the total loading of DDx to the Estuary as 7,900 kg/year. Nearly 60% of this estimate (i.e., 4,400 kg/year) was attributed to non-point agricultural runoff, based on consideration of the historical distribution of agricultural lands in the watershed. Point sources were estimated to contribute nearly 40% of total loadings (3,000 kg/year), whereas urban runoff was estimated to contribute the remaining portion (100 kg/year). No loading data for other chlorinated pesticides were found. Atmospheric deposition is not believed to be an important source of chlorinated pesticides to the Estuary (Sutton et al., 1996), but overall, there is a lack of sufficient data with which to fully assess contributions via this pathway (Frithsen et al., 1995). However, Frithsen et al. (1995) suggested that atmospheric deposition likely contributes a relatively small amount of chlorinated pesticides to the Estuary.

4.2.4.2 Metrics

The primary metrics used to characterize the temporal and spatial trends of pesticides in the Estuary were pesticide concentrations in various environmental media. Unless otherwise noted, pesticide concentration data discussed below are reported on a dry weight basis in sediment, a total basis in water, and a fresh weight basis in biota.

4.2.4.3 Temporal and Spatial Trends

The following discussion of temporal and spatial trends of chlorinated pesticides in the Estuary is organized by sampled medium: sediment, surface water, and biological tissue.

4.2.4.3.1 Sediment

Costa and Sauer (1994) evaluated the spatial patterns of DDx in sediment of Zones 3–5 of the Estuary and found that the highest concentrations were generally found near Philadelphia, where a maximum concentration of 130 µg/kg was found (Figure 4-38). Concentrations of DDx generally declined downstream and reached low levels near the mouth of the Delaware Bay, although a relatively high concentration of approximately 85 µg/kg was found near the Chesapeake and Delaware Canal (Figure 4-38). In general, the highest concentrations observed were present from River Miles 80 to 115 (Zones 2–4) (Santoro, 1998, based on Costa and Sauer, 1994).

Hartwell et al. (2001) evaluated sediment concentrations of chlorinated pesticides. In general, the highest DDx concentrations were found along the industrial corridor near Philadelphia (Zone 3) and concentrations steadily declined farther downstream (Figure 4-39; Table 4-17). Few DDx concentrations exceeded 200 µg/kg. Concentrations of chlordane, HCH, and HCB followed a spatial distribution pattern similar to that of DDx (Figure 4-40), with the highest concentrations of chlordane in the industrialized corridor ranging from 11 to 18 µg/kg (Hartwell et al., 2001).

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Frithsen et al. (1995) compiled information on chlorinated pesticides in sediments from such databases as NS&T, EMAP, and STORET to evaluate the spatial distribution of concentrations in seven segments of the Estuary (Table 4-18). Pesticide concentrations were found to be highest in the northern Estuary (i.e., Sampling Segments 1 and 2, Zones 2–3), with DDT concentrations ranging from undetected at the detection limit to 13 µg/kg, DDD concentrations ranging from 10 to 35 µg/kg, and DDE concentrations ranging from 19 to 37 µg/kg (Table 4-19). Although the highest sediment concentrations were observed in the northern Estuary, the largest reservoirs of pesticides were found in the Delaware Bay (i.e., Segments 6 and 7) because of its larger area. Segment 7 (Zone 6), for example, contained approximately 40% of the chlorinated pesticides reservoir (Frithsen et al., 1995).

Data to elucidate temporal trends in pesticide distribution in the Estuary are relatively limited. In terms of sediment, Reinfelder and Totten (2006) provide information on DDT concentrations in sediment cores collected from 1940 to 2000 at a station in Woodbury Creek, NJ (Figure 4-30). Concentrations of DDT showed one peak of approximately 600 µg/kg in the early 1960s and a second peak of approximately 500 µg/kg in the early 1970s. Concentrations declined substantially following the early 1970s following the ban on DDT use in the U.S.

4.2.4.3.2 Water

Summaries of pesticide concentrations in Estuary surface waters are not published. DRBC’s Boat Run monitoring program has historically collected surface water samples for pesticide analysis throughout the Estuary, but we found no published synthesis of these data.

On a broader watershed scale, Fischer et al. (2004) did provide information on pesticide concentrations in surface water and groundwater throughout the Delaware River Basin as part of the USGS NAWQA Program. Pesticide degradation products such as ethane sulfonic acids were often found at higher concentrations than parent compounds in both surfacewater and groundwater. Concentrations of atrazine and metolachlor were higher in streams draining agricultural lands than in streams draining urban areas (Fischer et al., 2004). The prevalence of metolachlor and atrazine throughout the Delaware River Basin was also noted by Hickman (2004) during a USGS NAWQA study conducted during 1998–2001, with most of the detected concentrations found in agricultural lands. The prevalence of these two compounds in the Estuary has, to date, not been fully investigated.

Long-term data on chlorinated pesticides in water were not available in the literature reviewed. Based on the decreases in sediment concentrations, it is likely that water column concentrations have similarly declined.

4.2.4.3.3 Tissue

Few data are available to directly explore spatial patterns of pesticide distribution in the Estuary biota. Based on data from Hauge (1993), however, the general spatial patterns of pesticide concentrations in tissue are similar to those identified for sediment, with relatively greater concentrations in the northern part of the Estuary. Hauge (1993) evaluated the concentrations of chlordane and DDx in fillet tissues of various fish species along the eastern and western borders of NJ with two sampling areas, identified as Camden and Delaware, located in or near the Estuary (Figure 4-41). Chlordane concentrations in American eel (163.96 µg/kg), white perch (146.15 µg/kg), and carp (275.38 µg/kg) from the Camden area have the highest concentrations. The highest concentrations of DDx were similarly found in the Camden area for American eel (258.33 µg/kg) and carp (371.83 µg/kg), whereas the highest concentrations in the Delaware area were

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found for channel catfish (297.59 µg/kg), white perch (358.33 µg/kg), and brown bullhead (295.07 µg/kg). Although the Delaware area included stations south of the industrialized corridor, 25% of the stations were located near Trenton.

Fischer et al. (2004) compared pesticide concentrations in fish tissue with sediment concentrations throughout the Delaware River basin, including the Estuary. In general, higher detection frequencies occurred in fish tissue than in sediment, suggesting that chlorinated pesticides may be present below laboratory detection limits in sediment, but become detectable as they bioconcentrate in fish. With respect to the presence of these chemicals in areas with different land uses (i.e., forest, agricultural, urban, and large river), DDx was frequently detected in all land use categories, most likely as a result of its widespread use. Chlordane and dieldrin were more frequently detected in fish from urban settings than from other areas, probably due to their commercial use as insecticides in residential areas (e.g., for termites). Figure 4-42 shows that fish from urban areas generally had higher tissue concentrations of DDx, chlordane, and dieldrin than other areas. Bioaccumulation of these chlorinated pesticides is demonstrated by the exponential increase in median concentrations observed in fish tissue compared to sediment (Fischer et al., 2004).

Ashley and Horwitz (2000) provide information on temporal trends in the fillet tissue concentrations of chlordane and DDx in parts of the Estuary for the periods 1986–1987 and 1998–1999. Chlordane concentrations generally decreased substantially during this time period (Table 4-20). For example, concentrations in American eel declined from 0.63 mg/kg in 1986–1987 to 0.015 mg/kg in 1998–1999. Concentrations of DDx showed both decreases (e.g., 1.3 to 0.373 mg/kg for eel) and increases (e.g., 0.074 to 0.163 mg/kg for largemouth bass) between the two sampling periods (Table 4-21) (Ashley and Horwitz, 2000). It is not known whether the increasing DDx concentrations were due to sampling variability or reflected broad scale increases.

4.2.4.4 Data Gaps / Information and Uncertainties

Overall, the pesticide data set is sufficient only to establish some general perspectives on the magnitude and distribution of pesticides in the Estuary. The available data are neither sufficiently comprehensive nor consistent across time, space, or constituent to establish a quantitative characterization with full certainty for all media.

As was the case with the other chemicals, the data compiled by Hartwell et al. (2001) are sufficient to provide a quantitative characterization of the concentrations of various pesticides in sediments throughout the Estuary, though not of localized conditions near individual sources. These data are, however, nearly a decade old so the degree to which they represent current conditions in the Estuary is not known.

Too few surface water summary data are available to support reliable estimates of pesticide distribution in the Estuary, though the raw data contained in the DRBC Boat Run database could be compiled and examined to support this analysis. Furthermore, the data for pesticides in fish tissue were collected in only a few zones within the Estuary, and consequently the total pesticide burden across Estuary fish is not fully known. Too few data are available with which to assess temporal trends, although the limited data that are available suggest that concentrations are decreasing. Also, too few data are available to understand the source strength for pesticides other than DDx.

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4.2.5 Metals

The term “metals” refers to a broad array of trace heavy metals (e.g., cadmium, copper, lead, mercury, zinc), metalloids (e.g., arsenic), and organometallic compounds (i.e., TBT). Metals have been recognized as an important group of chemical contaminants in the Estuary.

4.2.5.1 Sources

Concentrations of metals in water, sediments, and organisms in the Estuary have been measured since the 1960s, and numerous point and non-point sources have been identified. Major point sources include effluent discharges from WWTPs, industrial facilities, and power plants. Major non-point sources include atmospheric deposition, urban runoff, and agricultural runoff.

There are 190 major and 1,263 minor point-source discharges to the Estuary (Frithsen et al., 1995), with most of the major dischargers located upstream from Wilmington, DE (Zone 4 and north). The highest estimated loadings for the major dischargers are for zinc, copper, chromium, and nickel (Table 4-22). Total estimated point-source loadings of various metals to the Estuary range from less than 1,000 kg/yr for mercury to 1,000,000 kg/yr for iron. Loadings for arsenic, cadmium, chromium, copper, lead, and zinc range from approximately 10,000 to 100,000 kg/yr (Figure 4-43).

Of the major point sources of metals, WWTPs exhibit the greatest contribution to total loadings, followed by industrial facilities and, to a much lesser extent, power plants (Frithsen et al., 1995).

Important non-point sources of metals to the Estuary are atmospheric deposition and urban runoff. Each of these sources has been estimated to contribute to total non-point loadings, whereas agricultural runoff contributes a lesser amount (Table 4-23).

Estimates of total metals loadings to the Estuary from atmospheric deposition range from 364 kg/yr for cadmium to 17,403 kg/yr for zinc (Table 4-24). Figures 4-44 and 4-45 show the loadings from direct atmospheric deposition and the loadings from indirect atmospheric deposition via runoff from the watershed, respectively (Frithsen et al., 1995). Indirect inputs of atmospheric deposition on the watershed follow the same relative patterns as direct atmospheric deposition. Overall, zinc, mercury, and lead account for approximately 75% of the total metal loadings from atmospheric deposition.

Most mercury contamination in the Estuary is likely the result of atmospheric deposition from both historical and current releases due to anthropogenic activities (Reinfelder and Totten, 2006). According to Reinfelder and Totten (2006), compared to the atmosphere, the surface waters of the Delaware River basin are supersaturated with elemental mercury. Mercury volatilization fluxes showed a spatial trend from Zone 2 to Zone 6 in 2002, with measurements decreasing from 46 pmol/m2/h in Zone 2 to 16 pmol/m2/h in Zone 6 (Table 4-25), suggesting higher mercury concentrations in the more northern portions of the Estuary (Reinfelder and Totten, 2006).

In total, point sources are the major source of metals loading to the Estuary. Frithsen et al. (1995) estimated that point sources contribute approximately 64% of the total metals load to the Estuary compared to the approximately 36% contributed by non-point sources (Table 4-23). Point sources account for over half the loadings for five metals (i.e., chromium, copper, lead, silver, and zinc), whereas non-point sources account for over half the loadings of two metals (i.e., arsenic and mercury). For non-point sources, urban runoff contributes approximately 16% of total loadings, followed by atmospheric deposition (approximately 13%) and agricultural runoff (approximately 7%). Urban runoff is responsible for most of the metals loadings from non-point

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sources, with the exceptions of arsenic and mercury, for which the major sources are agricultural runoff and atmospheric deposition, respectively.

4.2.5.2 Metrics

The primary metrics used to characterize metals in the Estuary were concentrations in surface water, sediments, and biota, as well as atmospheric inputs. Surface water chemical concentrations are expressed as total, unless otherwise noted. Sediment concentrations are expressed on a dry weight basis and tissue on a fresh weight basis unless otherwise noted. In assessing ecosystem impairments to various DRBC zones, the 2004 DRBC 303(d) water quality report was consulted (DRBC, 2004). This document assessed impairments to the main-stem of the Estuary (see Table 4-14), and does not necessarily reflect the assessments of individual state agencies (DNREC, NJDEP, PADEP). Copper, for example, has been recognized on by DRBC as a source causing impairment, specifically for the lower portions of the Estuary (Zones 4 and 5, Table 4-14).

4.2.5.3 Temporal and Spatial Trends

A number of studies have been conducted on trace metals within the Estuary, including studies conducted by NOAA NS&T Program, USGS NAWQA, USGS National Mercury Pilot Program (NMPP), DELEP, and DRBC (Fischer et al., 2004; Brightbill et al., 2004; Hartwell et al., 2001; Santoro, 1998; DRBC, 1993). Trends identified from these data are discussed below by environmental medium. It is acknowledged that unpublished data by the Academy of Natural Sciences on metals concentrations in the Estuary may exist, though this data has not been consulted.

4.2.5.3.1 Sediment

Sutton et al. (1996) summarized elevated sediment concentrations of various metals in different parts of the Estuary. The elevated metals included cadmium, chromium, copper, lead, mercury, nickel, and zinc in the upper Estuary, lead, mercury, and zinc in the middle Estuary, and cadmium, chromium, lead, mercury, nickel, silver, and zinc in the lower Estuary. Sutton et al. (1996) also noted that the general spatial pattern for most metals was characterized by the occurrence of moderate concentrations above Philadelphia, highest concentrations in the greater Philadelphia area, and moderate to low concentrations in the lower Estuary.

A DRBC study conducted in 1991 reported that concentrations of chromium, copper, lead, mercury, and zinc exceeded screening-level sediment toxicity guidance values (i.e., effects range-low [ERL] and effects range-median [ERM] from Long and Morgan, 1990). Exceedances occurred at sampling sites within River Miles 80–115 (Zones 2–4), with the highest concentrations of cadmium, copper, lead, and zinc occurring between River Miles 97.5 and 107 near Philadelphia (DRBC, 1998, 1994). Table 4-26 shows the highest observed concentrations for these four metals compared to these screening-level sediment quality guidelines.

Frithsen et al. (1995) estimated mean metals concentrations in sediments from seven segments of the Estuary. The mean concentrations of most metals were highest in the upper two segments (1 and 2) of the Estuary (Zones 2 and 3), which include most of the areas near Philadelphia (Table 4-27). These upper segments receive relatively large metals loadings from both point and non-point sources (Frithsen et al., 1995). Although mean concentrations of most metals declined from the furthest to the lowest downstream segments, the mean concentration of arsenic was greatest in Segment 7 (Zone 6). Mercury concentrations were relatively consistent in Zones 3–5 (Segments 2–5), and lower in Zone 1 (Segment 1) and Zone 6 (Segments 6 and 7).

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A relatively large amount of information was collected on sediment chemistry and sediment toxicity in the Estuary in 1997 by Hartwell et al. (2001) as part of the NOAA NS&T Program. As was observed with many other constituents analyzed in that study, metals concentrations declined with increasing distance downstream from Philadelphia (Zone 3, Figure 4-46). There was, however, a relatively smaller peak in metals concentrations near the Chesapeake and Delaware Canal (Zone 5).

On a regional scale, Fischer et al. (2004) concluded that concentrations of all metals, except arsenic, were generally highest in streams associated with historical and/or current industrial activities, whereas the lowest concentrations were generally found in streams associated with agricultural areas (Brightbill et al., 2004).

Additional sampling for mercury was conducted at 28 stations under the NAWQA study as part of the USGS NMPP. Concentrations of total mercury and methylmercury were detected at all stations, with mercury concentrations ranging from 1.5 to 380 µg/kg, and methylmercury concentrations ranging from 0.01 to 8.7 µg/kg (Brightbill et al., 2004).

In general, there is an absence of long-term data within the Estuary, and only a few summary evaluations have been conducted that examined long-term trends in metal concentrations in Estuary sediment. For example, ANSP (1991) reviewed the available data metal concentrations in sediment from USEPA’s STORET database and other sources and concluded that there is evidence for a general decreasing trend among metals in the lower zone.

Relative temporal trends of metals in sediments have been assessed by examining the vertical distribution of contaminants in the sediment column. In 2002, Reinfelder and Totten (2006) collected sediment samples from two tributaries, Woodbury Creek and Oldmans Creek, located within Zone 4. In Woodbury Creek, sediment concentrations of mercury ranged from 218 to 1,350 µg/kg during a period from the mid-1940s to 2002. Two peaks in mercury concentrations in Woodbury Creek were found: one in 1950 and another in the late 1960s with concentrations between 1,000 and 1,500 µg/kg. The lowest mercury concentrations were found during the period of 1980–2000 (Reinfelder and Totten, 2006; Figure 4-31). In Oldmans Creek, mercury concentrations were generally lower than the concentrations observed in Woodbury Creek, ranging from 110 to approximately 900 µg/kg in all but one year (Figure 4-47). Concentrations in Oldmans Creek showed a single peak of 2,200 µg/kg that corresponded to about 1991. Reinfelder and Totten (2006) concluded that the higher mercury concentrations found in Woodbury Creek were due to a greater number of inputs from point sources than occurred for Oldmans Creek. The degree to which these trends in tributary creeks represent trends in the main-stem of the Estuary is not known.

4.2.5.3.2 Water

In general, metals concentrations in surface water of the Estuary tend to be within the range of concentrations found in other large rivers on the East coast (Church et al., 1993 as presented in Sutton et al., 1996; Table 4-28). However, the concentration of zinc in the Estuary was found to be greater than the concentrations found in all of the other rivers summarized by Sutton et al. (1996).10

Concentrations of total mercury and methylmercury were measured in surfacewater at five locations in the Estuary in 2002 by Reinfelder and Totten (2006). Concentrations varied seasonally in most zones and ranged from 6.4 to 75 picomolar (pM) for total mercury and <0.11 10 This evaluation did not include mercury.

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to 1.15 pM for total methylmercury. The highest concentrations of total mercury were found in Zones 4–6 (maximum concentration of 75 pM), whereas the highest total methylmercury concentrations were found in Zones 3, 5, and 6 (maximum concentration of 1.15 pM). However, the high variability observed across months precludes definitive determination of spatial trends. Overall, the authors concluded that the levels of mercury within the Estuary are within the range observed in other urbanized estuarine environments.

Various studies conducted between 1970 and 1990 have found that metals concentrations in surface water of the Estuary frequently exceed water quality criteria, particularly in the area near Philadelphia (Sutton et al., 1996). It was also found that mean concentrations of zinc and copper appeared to be decreasing within the entire Estuary, whereas nickel concentrations were increasing in the middle and upper zones of the Estuary (Sutton et al., 1996). Mean concentrations of other metals did not exhibit noticeable temporal trends.

4.2.5.3.3 Tissue

Various metals have been found in the tissues of fish, mussels, and oysters in the Estuary (Sutton et al., 1996). Mercury is the metal of greatest concern with respect to fish because it accumulates in fish tissues and can biomagnify in the food web. Because mercury accumulation in fish tissue can cause adverse health effects in humans, statewide and water body-specific consumption advisories have been issued by NJ and DE for the Delaware River and its tributaries.

Fish tissue (fillet) samples were collected in the Delaware River Basin watershed as part of the USGS NMPP and NAWQA studies (Brightbill et al., 2004). Only one of the 31 fish sampling locations was in the main-stem of the Estuary, with the remaining locations occurring in the river upstream of the northern Estuary boundary or in tributary creeks. Therefore, these data are best used to provide an indication of the mercury loadings to the Estuary rather than conditions in it. Of the 31 samples collected, tissue concentrations of mercury ranged from 0.03 to 0.35 mg/kg, with a geometric mean of 0.26 mg/kg (Brightbill et al., 2004). The highest fish tissue concentrations at levels deemed to pose a potential threat to human health and wildlife were found in the urbanized portion of the Estuary between Philadelphia and Wilmington. Fischer et al. (2004) found that mercury concentrations exceeded the human health criterion of 0.3 mg/kg at 22% of the 31 sampled sites, whereas concentrations at 87% of the sites exceeded the criterion of 0.1 mg/kg for protection of fish-eating birds and wildlife. Of the 20 basins studied in the NMPP, the Delaware River Basin was ranked eighth for elevated concentrations of mercury in fish fillets.

All of the trace metals of concern for the Estuary (as summarized by Sutton et al., 1996) have been found in the tissues of fish and shellfish oysters of the Estuary, and much of the available data suggest that these concentrations might be elevated relative to nationwide concentrations. Data collected by DRBC (as summarized by Sutton et al., 1996) for fish in the upper Estuary showed that metals in many fish exceeded the 90th percentile nationwide for those metals concentrations in fish. These exceedances were for white perch (copper, cadmium, chromium, and zinc), channel catfish (chromium and lead), white catfish (chromium), and brown bullhead (chromium). Channel catfish (chromium and lead) and white perch (chromium) from the middle Estuary were also found to exceed the nationwide 90th percentile for fish tissue burdens. Blue crab from the middle Estuary was found with copper, lead, and silver tissue burdens that were elevated (Sutton et al., 1996).

Recent analyses that could be used in support of an examination of temporal trends were not located in the available literature. An examination of monitoring data contained in the USGS National Contaminant Biomonitoring Program database

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(http://www.cerc.usgs.gov/data/ncbp/ncbpres.xls) revealed that between the early 1970s and late 1980s, there appeared to be decreasing trends for three metals, copper, lead, and selenium.

4.2.5.4 Data / Information Gaps and Uncertainties

The available data indicate that metals are present in the Estuary and that the loadings will continue given continuing inputs from point and non-point sources. In addition, metals are present in sediments and fish at concentrations that are elevated, either when compared to toxicity screening concentration limits or to monitoring data from across the nation. The available data are sufficient to generally characterize the source (both point and non-point) and general distribution patterns in the Estuary (typically higher concentrations near urban/industrialized areas). As was the case with the other chemicals, the data compiled by Hartwell et al. (2001) are sufficient to provide a quantitative characterization of the concentrations of various metals in sediments throughout the Estuary, though not of localized conditions near individual sources. Again, however, these data are nearly a decade old, so the degree to which they represent current conditions in the Estuary is not known.

With the exception of a recent monitoring study for mercury, no recent summaries of surface water data were uncovered. Existing regional databases (e.g., from DRBC Boat Run, USEPA STORET, and others) could provide sufficient data to characterize the distribution and magnitude of metals concentrations in Estuary surface waters.

Too few fish tissue summary data are available to support reliable estimates of the current magnitude and distribution of metals in Estuary biota. Based on historical data summaries, we know that metals have been elevated in fish and shellfish in the Estuary, and recent studies on mercury in the watershed document that it is pervasive and elevated when compared to other areas nationwide. The elevated presence of mercury in fish fillet in some portions of the Estuary has led to fish consumption advisories. It would be possible to compile additional data from USEPA’s STORET and EMAP databases (USEPA, 2006d, e), but based on the sample station distribution depicted in Figure 4-17a–c as well as inconsistencies in the analytes, it is expected that too few data could be compiled to support detailed analyses.

Too few summary data have been compiled for each of the summarized media above to assess temporal trends, though some limited data suggest that concentrations have decreased.

4.2.6 Nutrients

Nutrients in surface waters of the Estuary have been measured since the early 1900s and originate from both point and non-point sources. The two nutrients that have the largest impact on biological production in the Estuary are nitrogen and phosphorus. Dissolved inorganic nitrogen can be present in the form of ammonium (NH4

+), nitrate (NO3–), or nitrite (NO2

–), whereas dissolved inorganic phosphorus is typically found as phosphate (PO4

3–).

Nutrient loadings to the Estuary are the highest measured in any major estuary in the U.S. and among the highest in the world (USEPA, 1998b; Sutton et al., 1996). On a regional basis, nutrient loadings to the Estuary are substantially higher than loadings to Chesapeake Bay and the coastal bays of Maryland and DE. As of the early 1990s, the nitrogen loading to the Delaware Bay from both point and non-point sources was approximately 200 lbs. of total nitrogen/acre/year, whereas the phosphorus loading was approximately 50 lbs. total phosphorus/acre/year (USEPA, 1998b).

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Despite high loadings, eutrophication has not been a major problem in the Estuary, and many researchers have speculated that this is most likely due to the relatively high concentrations of total suspended solids that inhibit light penetration (Santoro, 1998; Frake et al., 1983). The bioavailability of nutrients to primary producers from biological and chemical processes is another potential limiting factor to eutrophication (Frake et al., 1983), however.

4.2.6.1 Sources

The major point sources of nutrients to the Estuary are the industrial and municipal WWTPs that are found primarily along the heavily urbanized Trenton-Philadelphia-Camden-Wilmington corridor, as well as along the Schuylkill River (Gottholm et al., 1994). This highly urbanized region has upwards of approximately 350 outfalls, including 181 industrial point sources and 153 municipal waste treatment plants, according to data for the period 1982–1987 (Gottholm et al., 1994).

Non-point sources of nutrients include surface runoff from agricultural areas, lawns, and roads, as well as loadings from atmospheric deposition. Non-point sources of nutrients are a concern because of the high percentage of agricultural land in the watershed, and the associated use of pesticides, fertilizers, and animal manure (Gottholm et al., 1994). Table 4-29 provides the estimated non-point loadings of nutrients to the Estuary for 1990, as well as projected loadings for 2020. A decrease in the loadings of both total nitrogen and total phosphorus is anticipated to occur in the future in response to continuing reductions in agricultural land use (Evans et al., 1993 as presented in Sutton et al., 1996).

Point and non-point sources of nitrogen contribute comparable loadings to the Estuary, whereas point sources contribute approximately four times more phosphorus than non-point sources (USEPA, 1998b). The primary sources of these nutrients are point sources along the urban corridor of the Estuary. Gottholm et al. (1994) estimated that industrial and municipal facilities contribute approximately 41% of the total amount of inorganic nitrogen entering the Delaware Bay.

4.2.6.2 Metrics

Nutrient sources to the Estuary are represented by both nutrient loadings and nutrient concentrations in water.

4.2.6.3 Temporal and Spatial Trends

Nutrient loadings in the Estuary tend to be highest along the urban corridor, and decrease downstream to the mouth of the Delaware Bay. The highest loadings occur between Trenton, NJ (River Mile 133.4; Zone 2/1e boundary), and Philadelphia, PA (River Mile 95.0; Zone 3/4 boundary), with municipal sewage treatment plants in the Philadelphia/Camden area being the largest contributors. Decreases in nutrient loadings begin to occur below Marcus Hook, PA (River Mile 78.0; Zone 5) and continue to decline to the mouth of the Delaware Bay.

Concentrations of total phosphorus, ammonia (NH3), ammonium (NH4), and nitrite-nitrogen along the Estuary during 1998–2003 are presented in Figures 4-48 through 4-50 (Santoro, 2004). The mean phosphorus concentration during this period ranged from approximately 0.1 to 0.2 mg P/L, and remained relatively constant throughout the Estuary with slight increases noted from Zones 2-4 (Figure 4-48). The mean total ammonia plus ammonium concentrations during the period 1998–2003 were highest just downriver from Trenton and decreased toward the Delaware Bay, only to increase again in the Bay, with mean concentrations ranging from approximately

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0.025 to 0.16 mg NH3 plus NH4-N/L (Figure 4-49). In general, mean ammonia and ammonium concentrations exhibited more variability at a given location than phosphorus, though concentrations were highest in Zones 2-4. Mean nitrite-nitrogen concentrations for the period 1998–2003 exhibited a spatial pattern different from those observed for phosphorus and ammonia/ammonium, with the highest mean concentrations located near Philadelphia in Zones 3 and 4 and the lowest concentrations observed in the Delaware Bay (Figure 4-50). Mean nitrite concentrations during that period ranged from approximately 0.2 to 2.0 mg/L. Sharp (personal communication) presented monthly-weighted annual average nutrient concentrations for nitrate, ammonium, and phosphorous from 1986-1988 (Figure 4-51). Like Santoro (2004), Sharp also showed nutrient maxima in Zones 2-4. The highest observed concentrations were found in the urban river region of Zones 3 and 4 (Figure 4-51).

Historical data suggest that, overall, nutrient concentrations in surface water of the Estuary have decreased over time. Long-term data from the DRBC Boat Run Program at Marcus Hook demonstrate substantial decreases in concentrations of ammonium, phosphorus, and nitrogen between 1967 and 1994 (DRBC, 1994 as presented in Sutton et al., 1996; Sharp et al., 1988). During this time, total phosphorus levels in the Estuary decreased four-fold (DRBC, 1994 as presented in Sutton et al., 1996). Ammonium showed a large decline in response to improvements in municipal sewage facilities. The historical range of ammonium concentrations was 0.5–3 mg N/L, compared to the more recent range of 0–0.5 mg N/L found in the early 1990s (DRBC, 1994 as presented in Sutton et al., 1996). In contrast, long-term nitrite data at Marcus Hook reported by Santoro (1998) show increasing concentrations between 1910 and the mid 1990s.

Additional information on historical trends of nutrients has been presented by Tetra Tech and Andrew Stoddard Associates, Inc. (2000). These studies presented trend information for total phosphorus, total nitrogen, and ammonium along the Estuary between 1968–1970, 1978–1980, and 1988–1990. Concentrations of each of these nutrients decreased between the late 1960s and late 1970s and then remained relatively stable. Phosphorus concentrations were similar throughout the Estuary, while total nitrogen concentrations were highest at approximately River Kilometers 110–120 (River Miles 68.4–74.6, Zone 5). Ammonium concentrations were the most variable, with peak concentrations between River Kilometers 130–150 (River Miles 80.8–93.2, Zone 4) in the late 1960s, 150–160 (River Miles 93.2–99.4, Zones 3–4) in the late 1970s, and 130–140 (River Miles 80.8–87.0, Zone 4) in the late 1980s.

The overall decrease in nutrients can be attributed to the focus of federal and state water quality programs on point source pollution abatement beginning in the 1960s (Sutton et al., 1996). Point source discharges from industrial and municipal facilities are now regulated under the DNREC NPDES, PADEP NPDES, and NJPDES permit processes. Over the two decades or more, non-point sources such as agriculture and development have gained increasing attention for their role in nutrient loading, though specific mechanisms for abatement have not been measurably achieved.

4.2.6.4 Data Gaps / Information and Uncertainties

The available nutrient data for the Estuary are temporally and spatially robust and can be used to characterize spatial and temporal trends as well as current nutrient conditions in the Estuary. There are no significant data gaps or uncertainties associated with this stressor alone. However, the interactions between stressors could be better understood. Kreeger et al. (2006) called for a better understanding of the interrelationship between sediment inputs, turbidity and light availability (physical traits), nutrient concentration and balance (chemistry), and other factors.

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4.2.7 Dissolved Oxygen

The concentration of oxygen in solution, or dissolved oxygen, is an important measure of general water quality because of its integral role in basic chemical and biological functions. Dissolved oxygen is continually consumed via respiration by bacteria, plants, and animals and can be quickly depleted if not replenished by air. This is especially true if nutrient enrichment of a water body exists, as with the effects of WWTP effluent. Ultimate oxygen deficiency of a water body results in anoxic conditions. Though stratification from density differences often results in oxygen deficiency throughout layers of lakes or small streams, systems such as the Estuary would not typically have this problem because of its dynamic flow and tidal influence.

Temperature and nutrient concentrations are the dominant abiotic parameters influencing dissolved oxygen dynamics. Increases in temperature decrease the capacity of water to hold oxygen. The interplay of enrichment in nutrients or other oxygen-demanding wastes in combination with high temperatures can result in degraded water quality, particularly lower dissolved oxygen concentrations. Monitoring data on dissolved oxygen reported for the Estuary are based on water quality investigations, which permit examination of trends across DRBC zone and time.

4.2.7.1 Sources

The principal source of dissolved oxygen reductions in the Estuary has been the presence of oxygen-demanding wastes. Sewage treatment plants and major municipalities have historically been the largest contributors of oxygen demanding wastes. Elevated temperatures coincident with drought and/or thermal effluent can exacerbate this stressor.

4.2.7.2 Metrics

The primary metric used to characterize dissolved oxygen in the Estuary was concentration or percent saturation in the water column. Biological oxygen demand, which is a measure of the maximum amount of oxygen consumption that can occur in water due to its load of suspended and dissolved wastes, is another commonly used metric.

4.2.7.3 Temporal and Spatial Trends

Dissolved oxygen deficits stemming from the release of heavy loads of oxygen-demanding wastes from both industrial and municipal sources posed some of the more identifiable water quality problems during early urbanization and development, but especially after 1900, when the region under went rapid and extensive development. Population growth, industry, water usage, and sewer discharges resulted in dissolved oxygen levels lower than 1 mg/L by 1914. By 1917, the Delaware River was reported to receive “one of the largest and most diverse industrial waste loads of any river in the nation,” including mostly untreated sewage from a population of more than two million people (Najarian Associates, Inc., 1991). The increased industrial activity occurring during World War II caused even greater degradation of water quality conditions, and by 1946, there was a 20-mile stretch of River that was anoxic from shore to shore and top to bottom (Albert, 1988).

Water quality improved with the advent of pollution control programs and development of primary and secondary WWTPs. By the early 1960s, all major cities along the River had primary or secondary WWTPs, although only about half of municipal and industrial discharges were treated (Levine, 2005; Najarian Associates, Inc., 1991). The effects of these changes on dissolved oxygen levels could be seen from 1946 to 1958, when levels rose at least 1 mg/L in the reach of the Delaware River between Philadelphia and Chester. Although dissolved oxygen

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levels were still low, the River was no longer anoxic. Dissolved oxygen is no longer a problem Estuary-wide, although oxygen deficits do occur on a more local scale.

Santoro (2004) presents multi-decade summer dissolved oxygen trends throughout the Estuary from 1967 to 2003 (Figure 4-52 depicts temporal and spatial trends). River Miles 84–111 refer to Philadelphia Boat Run sampling areas in which marked improvements in water quality are observed from 1967 to 2003. Furthermore, since 2001, the majority of all sampling locations through 2003 were > 4.5 mg/L. Also important to note is that recent sampling periods do not exhibit a reduction in mean concentrations along the industrial corridor (including Philadelphia) as dramatic as those in 1967 and 1980. Interestingly, an increase in dissolved concentrations persisted northward from Zone 5 through Zone 2 during 2003 sampling with concentrations > 7 mg/L in Trenton. An explanation for this is not provided in the literature. Sharp (personal communication) has observed dissolved oxygen saturation by season throughout the Delaware Estuary from 1990-2003 (Figure 4-53). Similar to Santoro (2004), Sharp showed an increase in dissolved oxygen approaching Zone 2, with another dissolved oxygen maximum observed near Delaware Bay at Zone 6. Zone 6 actually had the highest percentage of total samples fully saturated by dissolved oxygen, most likely due to tidal mixing (Figure 4-53).

DRBC (2004) has developed dissolved oxygen objectives for the Estuary in Zones 2–5. These objectives are presented in Table 4-30. An ultimate minimum concentration during spring and fall turnover months of 6.5 mg/L is enacted for all zones according to DRBC (2004). Spring and fall months result in shifts from former temperature extremes in which resultant water is better able to maintain dissolved oxygen. Zone 2 and the southern portion of Zone 5 have the highest year-round minimum dissolved oxygen concentration objectives, most likely due to the input of the Delaware River tributary to the north of Trenton and the tidal influences in Zone 5 facilitating oxygenation of the water column. The lowest minimum year-round concentration (3.5 mg/L) is characterized by Zones 3, 4, and the northern reach of Zone 5 (DRBC, 2004), due again to WWTPs and non-point runoff, which facilitate nutrient enrichment, thereby increasing microbial degradation.

DRBC (2004) also presented a dissolved oxygen objective for Zone 6 to be no less than 5.0 mg/L at any time (this is the highest compared to all other zones most likely due to tidal recirculation of the water). Zones 3, 5, and 6 have been observed to violate these objectives due to municipal point discharges, wet weather discharges, agriculture, and non-point sources (Table 4-31; DRBC, 2004). Poor water quality in these areas could be the result of a variety of factors, including effects from municipal WWTP effluent, agricultural runoff in Zones 5 and 6, and high temperature effects. Zone 6 as a whole, however, should not be viewed as oxygen depleted, again due to tidal effects recirculating the water column.

4.2.7.4 Data / Information Gaps and Uncertainties

Temporal trends in dissolved oxygen are well understood on both temporal and spatial scales. DRBC has been sampling dissolved oxygen since the early 1960s and the sampling data are extensive. The spatial representation of oxygen throughout the Estuary is also well exhibited, although the degree of reduction in concentration values throughout the Philadelphia region is not entirely understood.

4.2.8 Other Chemicals

In addition to the previously discussed organic chemicals (petroleum, PAHs, PCBs, dioxins/furans, metals, pesticides), a number of other organic chemicals can potentially occur in the Estuary. These include other VOCs, phenols, and phthalates, as well as other SVOCs that are

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present on USEPA’s Target Compound and Priority Pollutant Lists. In addition, organo-tin compounds, including TBT, that have been used historically in anti-fouling paints on ships are another potential chemical stressor. Sulfur oxides (SOx) and nitrogen oxides (NOx) are additional regional chemical stressors that can be deposited to the Estuary, largely as a result of atmospheric input.

Virtually no monitoring data are available for these other organic chemicals in the Estuary. Most of the available information is focused on 1,2-dichloroethane and tetrachloroethene, which were specifically identified by the Toxic Task Force of DELEP (as referenced in Sutton et al., 1996) as toxic substances that could occur at levels detrimental to the Estuary. The Task Force identified these chemicals based on their consistent presence in the upper Estuary adjacent to industrialized areas potentially at concentrations that could pose human health risks, as summarized by the Academy of Natural Sciences of Philadelphia (ANSP, 1991). Given general consideration to toxicity, the concentrations of these compounds needed to pose aquatic life risks will be much higher than those associated with human health risks, and it is likely that these organic compounds do not pose a threat to the Estuary’s ecology.

Fischer et al. (2004) studied the distribution of SVOCs in streambed sediments as part of USGS NAWQA for the Delaware River basin from 1998 to 2001. As mentioned earlier, this comprehensive study included stream locations as far north as the Appalachian Plateau in New York State through the Piedmont and Coastal Plain regions, but also covered the main-stem of the Estuary. The study did not separately analyze data for the Estuary, so no specific conclusions are possible. Nevertheless, the findings do provide information on the potential presence of other organic compounds. In addition to PAHs (discussed previously), phthalates and phenols were detected frequently and at the highest concentrations in urban areas and the main-stem of the River, respectively. Separately, DELEP (1996) noted an increasing trend in phenol concentrations throughout the Estuary accompanied by a decreasing trend in VOCs closer to the Bay mouth.

In the watershed-wide study, Fischer et al. (2004) reported that chlorinated solvents and disinfection by-products were the most commonly detected VOCs (Figure 4-54). Actual concentrations of VOCs were relatively low and relatively consistently below 1 ppb (Fischer et al., 2004). These VOC data were consistent with the results of water analyses performed by DRBC in 1997 as part of its Boat Run data throughout the main-stem of the Estuary, which detected very few VOCs at a 1–2 ppb detection limit (Santoro, 1998).

In addition to these more conventionally considered toxic chemicals, Kreeger et al. (2006) lists chemicals of emerging concern throughout the Estuary for which even fewer monitoring data exist. These include perfluorinated compounds, the flame retardant polybrominated diphenyl ether (PBDE), and pharmaceuticals and personal care products. Currently, the minimal monitoring information present for these chemicals is limited to some information on the levels of PBDEs in fish fillet tissue and sediment. Ashley et al. (2006) and Toschik et al. (2005) are the sole studies showing the levels of these compounds in the Estuary.

Ashley et al. (2006) compared total PBDE concentrations in sediment (dry weight) with total PCB (a similarly behaving chemical) concentrations in three locations adjacent to Philadelphia (Zone 3; Bristol, Bridesburg, and Little Tinicum Island – all in PA) plus Delaware City, DE (near the Chesapeake and Delaware Canal, Zone 5). Figure 4-53 shows comparative results, where total PCBs were close to an order of magnitude higher than PBDEs, which were similarly low across all stations.

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Ashley et al. (2006) also examined total PBDE concentrations (fillet) in American eels across the Estuary. Results suggest that total PBDEs are highest in Trenton (Zone 2) and adjacent northern reaches of the Estuary, but low sample size (n < 15 total eels) prevents definitive conclusions from being drawn. Figure 4-55 shows total PBDEs for eels on a wet weight and lipid-normalized basis where individual eels are included. Highest PBDE concentrations are approximately 5.5 mg/kg lipid north of Trenton and approximately 3 mg/kg lipid near Trenton.

Toschik et al. (2005) likewise looked at total PBDEs throughout the Estuary, but with osprey eggs. Osprey eggs were collected in the nontidal Delaware River, the northern Estuary (Trenton-Chesapeake and Delaware Canal, Zones 2–4), the central Estuary (Zones 4 and 5), and the southern Estuary/Delaware Bay. Table 4-32 shows mean total PBDEs and associated congeners across sampling regions where the northern sampling region (Trenton-Chesapeake and Delaware Canal) had the highest observed mean total PBDE concentration (0.57 mg/kg, fresh weight). Mean values decreased south towards the Delaware Bay. Toschik et al. (2005) also looked at perfluorinated compounds across the Estuary where a subset of data is presented in Table 4-33. Similar to PBDEs, perfluorinated compounds were highest in the northern Estuary with a maximum mean of 0.29 mg/kg, fresh weight (perfluorooctanesulfonate) (Toschik et al., 2005).

Organo-tin compounds also have been detected in the Estuary, though the available monitoring data appear to be limited to that provided by Hartwell et al. (2001) as part of the NOAA NS&T Program (see Figure 4-16 for sampling stations), which also analyzed sediments for butyltins, including TBT. Butyltins were detected at most freshwater stations (Figure 4-56) at concentrations generally on the order of 10 µg/kg or less (dry weight), but there were spikes of higher concentrations at Stations 13 (31.49 µg/kg), 17 (48.09 µg/kg), and 57 (23.99 µg/kg) (Hartwell et al., 2001). High concentrations at these stations might be attributable to maritime operations near Stations 13 and 17 (located just south of Philadelphia), and tributary discharge at Station 57 (Dividing Creek). These data are sufficient to provide an indication of the spatial distribution of these compounds in the Estuary. Monitoring data to examine historical trends were not located.

Overall, too few data are available to reliably assess the presence, source, magnitude, and distribution of these other organic chemicals in the Estuary. It is likely that additional monitoring data for some of these compounds exists within electronic databases (e.g., for VOCs and SVOCs on the USEPA’s Target Compound List), but heretofore, these compounds have not been identified as important chemical stressors potentially affecting the Estuary’s ecology. Other chemicals, including perfluorinated compounds, PBDE, and pharmaceuticals and personal care products, simply have not been the focus of much sampling.

4.3 Biological Stressors

Biological stressors are changes to the character and composition of the ecological community that occur outside of natural ecological succession processes. Biological stressors include introduced, non-native species that may out compete or displace native species (i.e., become invasive), thereby potentially altering habitat and the food web. Other biological stressors include reduction of local fish or shellfish stocks due to harvesting, potentially resulting in concomitant reductions in the food supply for predators or, in the case of clams and oysters, concomitant changes in habitat characteristics that influence benthic dwelling species. Pathogens and parasites are additional biological stressors that occur in the Estuary.

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4.3.1 Invasive Species

The rate of introduction of invasive species in the U.S. has increased exponentially over the past 200 years (Carlton, 2001; Ruiz et al., 2001). These introductions come mainly from ballast water and hull fouling. Ballast water is the largest source of marine invasions throughout the world (Wonham et al., 2000; Carlton, 2001; Ruiz et al., 2001; Cooper et al., 2002; Smithsonian Environmental Research Center, 2004; USEPA, 2006c). Invasive species introduced within the Estuary, including aquatic plants and animals and terrestrial plants, can have major ecological effects as well as economic impacts, and are a potentially significant threat to both estuary food webs and wetland habitats.

Invasive species introductions to the Estuary occur mainly as a result of maritime operations (contamination via ballast water and hull fouling) and the commercial/recreational fishing industry (seafood industry and aquarium trade) (Kreeger et al., 2006). According to Kreeger et al. (2006), there is not much comprehensive data available to date on the impacts of invasive species on the distribution and population dynamics of native species. A listing of potential vectors for invasive species introductions and their impacts is shown in Table 4-34. The major effects of invasive species on aquatic and terrestrial ecosystems include habitat destruction and the loss of biological diversity through the introduction of new predators, competitors, disturbers, parasites, and diseases (Carlton, 2001). Figure 4-57 illustrates the number of species introduced to the Delaware Bay by vector.

4.3.1.1 Metrics

Invasive species introduced to the Estuary can be measured by either the number of species (aquatic and terrestrial) or by the total acreage (terrestrial).

4.3.1.2 Temporal and Spatial Trends

Specific data pertaining to temporal trends of invasive species introduction to the Estuary are not available. However, trends over time of introductions for individual states were obtained from the USGS Non-indigenous Aquatic Species database.

The number of aquatic and terrestrial invasive species introduced to the state of DE up through 1950 was ten; this number increased to 36 introduced species by 2006 (USGS, 2006a). The state of NJ has seen a steady increase in the number of introduced species, from 12 prior to 1900 to 67 in 2006. PA has also incurred a constant increase of invasive species introductions over the last 100 years, from 12 species introduced prior to 1900 to 102 introduced invasive species by 2006. As of June 2005, USGS (2006a) reports that there are a total of 49 known invasive species located within the Estuary, as shown in Table 4-35.

Table 4-36 lists the most common invasive plant species found in each state that impact the nearshore and wetland habitats along the Estuary. The common reed, Phragmites australis, is one of the invasive plant species that has been studied most along DE’s shores. Phragmites, once a native species in DE, has been nearly eliminated by a non-native variation that originated in Eastern Europe. These introduced forms of P. australis are aggressively expanding in coastal wetlands, creating dense monocultures due to a vast underground system of roots and rhizomes (Ehrenfeld, 2006). P. australis can be found in disturbed habitats, dredged material disposal areas, reconstructed wetlands, marshes, riverbanks, and ditches (Faulds and Wakefield, 2006; Swearingen et al., 2002). The degree to which P. australis has impacted DE’s coastal wetlands can be seen in Figure 4-58. As a result of its rapid growth, P. australis occupies 12–16 ha, roughly one-third of DE’s tidal wetlands (DELEP, 1996; Jones and Lehman, 1987). In a Delaware DNREC study conducted in 2000, P. australis was identified as a priority non-native

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species affecting two reserves, Upper Blackbird Creek and Lower St. Jones River (Delaware DNREC, 1999). P. australis composes 11.05% of the wetland vegetation in the Upper Blackbird Creek watershed and 13.38% in the Lower St. Jones River watershed, as seen in Table 4-37.

4.3.1.3 Data Gaps / Information and Uncertainties

Comprehensive data are lacking on the rate and spatial extent of invasive species introductions to the Estuary. Also, few measures are available to understand how these species affect the Estuary’s ecology. The recent data on the distribution of Phragmites wetlands on coastal DE does provide a good summary of the distribution of that stressor. Similar data for the NJ shoreline were not found, however. Overall, the full scope and magnitude of invasive species distribution are far from known.

4.3.2 Reduction of Local Stocks

The Estuary serves as a breeding ground, nursery, and a forage area for more than 200 resident and migrant fish species, as well as home for a number of shellfish species (Santoro, 2004; Sutton et al., 1996). Many of these species are harvested recreationally or commercially and collectively constitute the Estuary fishery resource. Important species of the fishery include, but are not limited to, American shad (Alosa sapidissima), sturgeon (Acipenseridae family), Atlantic menhaden (Brevoortia tyrannus), striped bass (Morone saxatilis), weakfish (Cynoscion regalis), American eel (Anguilla rostrata), Eastern oyster (Crassostrea virginica), and blue crab (Callinectes sapidus). Table 4-38 lists the various species that significantly contribute to the fishery of the Estuary (Killam and Richkus, 1992).

Over the past century, there has been a substantial decline in the abundance of both fish and shellfish species (Michels and Greco, 2005; Santoro, 2004; Weisberg et al., 1996; Dove and Nyman, 1995). A number of factors have been implicated as potential causes in decline, including poor water quality, entrainment and impingement resulting from the intake of cooling water at electric generating facilities, habitat loss, and access changes. Human fishing pressure, both recreational and commercial, is an additional stressor placed on fish stocks. In some cases, harvest pressure is clearly a determinant in overall population abundance. In other cases, human harvest could have caused an initial decline in the population and other factors are delaying recovery. The interaction of these collective stressors makes it difficult to discern the precise cause of population declines.

4.3.2.1 Metrics

The metric used to gauge fishing pressure is the size of the annual harvest. Harvest numbers are tracked annually and are typically presented in pounds. Data are available for a large number of commercial and recreational species. However, harvest numbers are not a direct indicator of the magnitude of the impact of this stressor on populations, given that harvest itself is a function of a number of factors (e.g., economic, other causes of population decline).

Estuary-wide information regarding reductions of local stocks due to impingement and entrainment of fish and other aquatic life was not located in the available literature, although this is a potentially important stressor in the Estuary. USEPA (2002) evaluated the potential loss of fish as a result of impingement and entrainment due to water intake at power plants and manufacturing facilities in the lower Estuary (Zone 5) and concluded that the cumulative impacts could be significant, even though the impacts from individual plants might not be. Estuary-wide information on this stressor is not available, but USEPA’s (2002) evaluation did focus on the part of the Estuary where water intakes (and thus impingement and entrainment risks) were greatest. Species-specific population evaluations were not conducted, however.

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4.3.2.2 Temporal and Spatial Trends

Currently, the recreational fishing industry is significantly larger than the commercial fishing industry of the Estuary, as observed in Figure 4-59. Data for 13 species caught both recreationally and commercially in DE waters in 2004, show that the recreational harvest accounted for 64.6% (1,787,771 lbs.), and the commercial harvest accounted for 34.4% (980,091 lbs.). Harvest trends are discussed below for some recreationally and commercially important species.

4.3.2.2.1 American Shad

Throughout the 19th century, the Estuary was heavily populated with American shad. Miller (1995a) state that from 1896 to 1901, “the catch of shad in the Delaware River was greater than in any other river system on the Atlantic coast, averaged 5,445 to 6,350 metric tons, or 12–14 million lbs. annually.” After 1901, the harvest of the American shad quickly declined, falling below 500,000 lbs. by 1920. From 1920 to the 1980s, the harvest has remained relatively consistent with annual harvests of less than 0.5 million lbs. (Chittenden, 1974) (Figure 4-60). The decline in the shad population has been attributed to excessive harvesting, as well as chemical pollution, fish losses due to entrainment and impingement at power plant facilities, and loss of spawning grounds due to the construction of dams within the Estuary and its tributaries (USEPA, 1998b; Sutton et al., 1996; Miller, 1995a). Current harvest of shad is less than one-tenth of the early 20th century levels.

4.3.2.2.2 Sturgeon

The shortnose sturgeon was once very abundant in the Estuary but today is recognized as both a federal and state (DE, NJ, and PA) endangered species (O’Herron et al., 1995; Killam and Richkus, 1992). The shortnose sturgeon fishery began in the 1850s and was in high demand for its caviar and smoked flesh from 1870 through the late 1890s, averaging 3.5 million lbs. annually. The historical trend of the shortnose sturgeon harvest over time is illustrated in Figure 4-61. Between 1891 and 1901, the harvest decreased by more than 95% with an average harvest of 183,000 in 1901; this decline has continued and has remained steadily under 10,000 lbs. annually since 1930 (Killam and Richkus, 1992). There is currently no commercial fishery for shortnose sturgeon in the Estuary (Sutton et al., 1996).

4.3.2.2.3 Atlantic Menhaden

Atlantic menhaden is considered a key component of the commercial fishery in the Estuary. Though the beneficial uses as fertilizer and bait were discovered in the early 1800s, data on the menhaden harvest were not recorded until the 1950s. From 1950 to the early 1960s, the harvest of the Atlantic menhaden was high though variable (as shown in Figure 4-62; Killam and Richkus, 1992), yet by 1962 stocks decreased, forcing the two processing plants along the Delaware River to close in 1966 (Sutton et al., 1996). There was an increase in the abundance of Atlantic menhaden observed after the plants were closed, suggesting that harvest pressure was an important contributor to the decline.

4.3.2.2.4 Striped Bass

Striped bass, a species of historical importance to both the commercial and recreational fisheries of the Estuary, is once again becoming an important component of recreational fisheries. As shown in Figure 4-63, declines in the commercial harvest of striped bass began prior to 1900 (approximately 25,000 lbs.) and remained low until the early 1940s; variable increases were observed over the next 30 years reaching a peak of approximately 600,000 lbs. in 1977 followed by a decrease to < 10,000 lbs. by the 1980s (Killam and Richkus, 1992).

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Concern about the consequences of over harvesting led to the development of protective regulations by the States of DE and NJ. Statewide commercial bans on striped bass fishing were passed in 1984 by the State of DE and in 1996 by the State of NJ, and a total moratorium on both commercial and recreational fishing was enacted in DE from 1985 through 1989 (Sutton et al., 1996; Killam and Richkus, 1992). A moratorium was also enacted in nearby Chesapeake Bay during the same period. Figure 4-64 illustrates an increasing trend of recreational harvests between 1982 and 2002 for the entire Atlantic coast. Since 1989, the harvest of striped bass has continued to increase from >250,000 lbs. to an average of 3,500,000 lbs. by 2002 (Santoro, 2004). This information is not solely applicable to the Delaware Estuary, but implies a coast-wide rebound in recreational harvests over a twenty-year period.

Over harvesting was one of many stressors attributed to striped base declines. Other potentially important stressors influencing population abundance include diminished access to spawning areas due to dams and entrainment and impingement from power point intakes (Miller, 1995b).

4.3.2.2.5 Weakfish

Weakfish are important to both the commercial and recreational fisheries of the Estuary, contributing 19–61% of the recreational harvest and 10–50% of the commercial harvest between 1968 and 1987 (Killam and Richkus, 1992). Figure 4-65 represents the harvest of weakfish from 1890 to 1990. The harvest trend of weakfish shows large peaks in both 1958 and 1980. Killam and Richkus (1992) report that weakfish harvest decreased from 78.5 million lbs. in 1980 to >10 million lbs. by 1992, concluding that “weakfish were over-exploited and at a low level of abundance by 1990.”

4.3.2.2.6 Eel

The American eel fishery is important to the commercial and recreational fisheries of the Estuary. Eel harvests over the past century are shown in Figure 4-66. From the 1890s until 1901, the eel harvest ranged between 320,000 and >400,000 lbs. annually. The eel fishery underwent a dramatic decrease from 1901 to 1942, increased steadily between 1943 and 1970, and has remained relatively constant with an average annual harvest between approximately 200,000 and approximately 475,000 lbs., with the exception of an annual harvest of 750,000 lbs. in 1984 (Figure 4-65; Killam and Richkus, 1992).

4.3.2.2.7 Oyster

Oysters have been harvested in the Estuary since pre-colonial times. Oyster harvest between the late 1800s and the mid 1950s ranged from approximately 1.0 to 3.2 million bushels. Since then, the oyster fishery has been substantially reduced due to two parasitic diseases, MSX and Dermo (see Section 4.3.3). These parasites caused high mortality rates in 1957 and 1990 to the oyster population along the NJ shoreline (Figure 4-67; Partnership for the Delaware Estuary, 2002). Since the onset of MSX and Dermo, the oyster harvest has remained below 0.5 million bushels per year. It must also be noted that parasites alone did not cause significant declines in the oyster fishery. Figure 4-66 shows that a substantial decrease in harvested bushels (from 1.5 to 3.2 million bushels down to ~1.0 million bushels) was observed in the 1930s, 20 years before the onset of MSX, possibly due to fishing pressure and/or habitat loss.

4.3.2.2.8 Blue Crab

Blue crab became an important fishery in the Estuary at about the same time that the oyster stocks were reduced due to disease (Figure 4-68), with landings in DE exceeding those in NJ for the period 1972–2002 (Figure 4-69). According to Killam and Richkus (1992), the harvest of blue crabs has greatly increased to approximately 10 million lbs. in 1990, rendering this species the

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primary contributor to Estuary harvest. Over harvesting does not currently seem to be a major concern in the abundance of blue crab (Epifanio, 1995).

4.3.2.3 Data / Information Gaps and Uncertainties

The available information on harvest is adequate to determine the general magnitude of harvest pressure on species within the Estuary historically and currently. However, more information on catch-independent population assessments would be useful for providing an unbiased assessment of harvesting pressure across the entire Estuary. State-specific monitoring datasets exist (Sharp, personal communication), but analyzing them was beyond the scope of this project. Too few data also are available to assess the degree to which local stocks are reduced due to impingement and entrainment of fish and other aquatic life, however an assessment by USEPA (2002) suggests this cumulative impact could be significant in at least Zone 5. A lack of available trophic models analyzing the ecosystem-wide effects of fishing pressure is another concern in analyzing the magnitude of this stressor.

4.3.3 Pathogens

Pathogens are agents that cause disease. Pathogens can be non-living but typically the term is used to refer to living organisms such as bacteria or fungi. In the Estuary, the presence of two pathogens that affect shellfish has been relatively well documented because of their impacts on commercial shellfish harvests. Pathogens that affect human health are also present, although these are not the subject of this report on ecological stressors.

The two pathogens known to cause shellfish disease are:

1. Haplosporidium nelsoni, more commonly known as MSX, is a single celled parasite. The MSX disease was first identified in the lower Delaware Bay in 1957, causing massive oyster mortalities (90–95%) (Ewart and Ford, 1993). It is not clear how MSX was introduced to the Estuary, although it is believed that MSX was inadvertently introduced to the Chesapeake Bay through the importation of the non-native oyster, Crassostrea gigas, in the 1930s. As a spore-forming parasite, infections of MSX are found in the oyster’s gills. From the gills, the parasite (present as a plasmodium) enters the bloodstream and tissues, killing the oyster. Prevalence of MSX is regulated by salinity and temperature. MSX is rarely found in waters where the salinity is below 10 ppth, but is capable of spreading rapidly at salinities greater than 15 ppth and temperatures above 20ºC.

2. Perkinsus marinus, or Dermo, is a warm-water, protozoan parasite. It was introduced to the Delaware Bay in the mid-1950s, when infected seed oysters were transplanted from the lower Chesapeake Bay (Ewart and Ford, 1993). The transmission of Dermo is via oyster to oyster as parasites are released by the disintegration of dead oysters. Once in the water column, the parasite is ingested by neighboring oysters and invades the lining of the digestive system. Like MSX, Dermo incidence in oysters is regulated by temperature and salinity. Dermo spreads most rapidly among the oyster population at temperatures above 25ºC. Higher salinities (above 12 ppth) and drought conditions are also favorable conditions that promote the spread of infection.

Though extensive data do not exist, there is no evidence that other pathogens of ecological consequence are occurring in the Estuary.

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4.3.3.1 Metrics

The primary metric used to characterize pathogens with the potential to influence ecological conditions in the Estuary is disease prevalence in shellfish.

4.3.3.2 Temporal and Spatial Trends

In NJ, oyster populations suffered high mortalities in 1957 and 1990 due to diseases caused by MSX and then Dermo. The effects of these parasites on the oyster populations in the Estuary are shown in Figure 4-66. MSX first occurred in 1957, and within two years, nearly 95% of all oysters on planted grounds and 50% of all seed beds had been decimated (Partnership for the Delaware Estuary, 2002; USEPA, 1998b). Oyster populations gradually recovered, but in 1990, they were reduced by a second disease, Dermo, and have remained at relatively low levels since that time.

Information on spatial trends in the incidence of these diseases was not located in the literature review.

4.3.3.3 Data / Information Gaps and Uncertainties

Information on spatial extent of the shellfish beds affected by MSX and Dermo was not located. The extent to which the loss of shellfish beds may have affected resident benthic infauna and intertidal production is not known.

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5. Preliminary Ranking of Stressor Magnitude

As discussed in previous sections of this report, stressors are distributed throughout the Delaware Estuary, but at varying strengths. This section synthesizes the previously presented information to preliminarily rank individual stressors with respect to their relative strength in different locations throughout the Estuary. These relative rankings are developed to help elucidate differences in spatial distribution, where they exist. During the next step of the Delaware River Study, the preliminary stressor rankings presented here will be further refined and integrated into an overall multi-stressor regional risk assessment. This subsequent risk assessment will characterize, rank, and determine the key stressors that are most significantly influencing the current ecological conditions in the Estuary. The preliminary stressor rankings presented here represent a critical transition into the overall regional risk assessment work.

Our relative rankings were based on the distribution of the individual stressors rather than the distribution of the source of the stressor. For example, we examined the distribution of a given chemical in environmental media rather than looking at the distribution or density of outfalls or other potential sources. We used stressor-specific data in lieu of source data because stressors are the entities that can induce adverse effects in the Estuary system. Stressor-specific data were also relied upon because an evaluation of stressor-response linkages will be a critical element of the subsequent regional risk assessment. If ultimate management objectives are developed to address source control, the information on stressor sources presented in Sections 3 and 4 can be directly used to identify the general types of sources that contribute most importantly to any given stressor.

The following sections describe the overall process we used to derive our relative rankings and present our results. Key uncertainties and data / information gaps are then discussed.

5.1 Methods and Approach

The relative magnitude rankings were derived based on the collective consideration of the available data. Rankings were assigned to each stressor based on its relative magnitude within each DRBC zone of the Delaware River. We used the DRBC zones as our organizing spatial elements for a number of reasons, but importantly because much of the available monitoring data for the river is presented in that manner. In addition, we believe that use of an existing management construct with which people are familiar will facilitate communication and interpretation of our findings by the broader group of Estuary stakeholders.

We followed the conceptual ranking approach outlined by Landis (2005) for stressors and stressor sources to develop our rankings. Under this approach, stressors were assigned to a relative magnitude category as follows:

� High—Highest source loading or greatest stressor magnitude across the Estuary;

� Medium—Moderate source loading or moderate stressor magnitude across the Estuary;

� Low—Lowest source loading or lowest stressor magnitude across the Estuary; or,

� Absent—Stressor absent from area.

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As an important caveat, these relative magnitude rankings do not convey absolute magnitude and have no meaning outside of the context of the Estuary and this specific study. For example, a stressor magnitude characterized as “high” simply means the stressor is occurring at a given location at the highest levels that have been measured or predicted for the Estuary. It does not imply that it is high when compared to other locales outside of the Estuary, nor does it imply it is high when compared to some risk-based threshold. In fact, it does not convey relative risk in any way and should not be interpreted in that way. The relative risk contribution of each stressor will be examined during the ecological conditions characterization portion of the Delaware River Study.

Quantitative metrics were used in some instances to support the preliminary stressor ranking, but we also relied on qualitative evaluations of the variety of available data to discern relative magnitude. The reasons for this were three-fold. First, in most instances, no one quantitative metric could capture all aspects of a stressor’s distribution or measures were not consistently available for all zones. Second, we judged a ranking approach that considered the full weight of the available data to be potentially more robust than that which relied on a single metric. For example, for some chemical stressors, we considered loadings along with concentration trends in sediments and fish to characterize relative distribution, rather than relying on any one piece of information alone. Third, much of the information on stressor distribution summarized in the available literature was presented in the context of spatial trends across zones based on other researchers’ synthesis of a variety of different types of data. One of our objectives was to utilize such existing data syntheses to support our rankings.

In assigning our preliminary rankings, we used recent data to the extent possible to best characterize the current conditions in the Estuary. In many instances, however, the most recent data were collected nearly a decade ago or more. Therefore, the degree to which our rankings reflect current conditions is not known. Furthermore, for some stressors, we simply did not have enough information to evaluate relative magnitude across the Estuary, even though we might have very localized information about the stressor for a given zone. Rather than extrapolate based on a limited data set, these stressors were treated as unknowns in our rankings.

5.2 Relative Ranking Stressor Magnitude

Table 5-1 describes the criteria we used to characterize magnitude for each stressor, and Table 5-2 depicts the relative magnitude of each stressor across each of the DRBC zones. The results of our rankings are discussed below. Too few data were available to examine spatial trends for the physical stressor related to barriers to fish access in tributaries, the chemical stressors dioxin/furans and miscellaneous organic chemicals, and biological stressors related to invasive species.

5.2.1 Physical Stressors

A variety of data were used to characterize physical stressor distribution. In the case of water volume, two different ranking metrics were used to address potential differences in the time course or type of the possible adverse effects that could occur. For example, total water withdrawal is a stressor because it removes water from the system, but because much of the removed water is returned to the system after use, the effects of this stressor are considered transient. Water withdrawal, however, can lead to impingement and entrainment of aquatic life, and potentially long-term cumulative impacts on aquatic populations. Water consumption (withdrawal without return) results in a permanent removal from the system, and therefore, can also result in long-term changes to receptors. . Both ranking metrics were considered to be of equal importance.

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Overall, there is no consistent regional pattern to the distribution of physical stressors in the Estuary except that most physical stressors have their lowest magnitude in Zone 6 (Delaware Bay). Several of the stressors have their greatest magnitude in the upper reaches of the Estuary in Zones 2 and 3, linked largely to habitat alteration associated with urbanization and industrialization and/or the presence of a higher number of potential sources in these regions. For example, habitat loss is greatest in Zones 2 and 3 and extending into Zone 4, where development has resulted in a significant change in character of the available habitat over time. Suspended solids is ranked greatest in Zones 4 and 5, due to the presence of the ETM in these areas. Zones 2, 3, and 6 are labeled as “Low” due to low observed TSS/seston concentrations.

Ranking of water volume changes due to withdrawal and consumption vary depending upon the metric used. On a total withdrawal basis, Zone 5 has the greatest stressor strength, due largely to withdrawals by electric generating facilities. On a consumption basis, the stressor is of equal magnitude in Zones 2 through 5. Regardless of the metric, water volume stressor is ranked lowest in Zone 6.

Temperature stressor magnitude is greatest in Zones 3 and 4, where DRBC’s temperature criteria have been exceeded. Though temperature criteria exceedances have not been documented in Zone 2, this area was given a stressor ranking of medium because general urbanization has been linked as a possible contributor to temperature stress (DRBC, 2004). Urban land development is less in Zones 5 and 6 and therefore, these areas were ranked lowest for temperature stressor magnitude.

Salinity as a stressor was judged to have its greatest magnitude in Zone 4, where the furthest upstream movement of the salt line has been identified. Upstream Zones 2 and 3 are outside of the current intrusion extent and downstream Zone 5 and 6 are more naturally saline waters. Though Zones 5 and 6 can be subject to increased salinity as a result of decreased freshwater flows, we have not included salinity as a stressor in these zones because the animals and plants that inhabit this zone will be those adapted to the range of salinities that occur naturally in these areas. Increased salinity in Zone 6 can, however, lead to an increased prevalence of oyster disease because higher salinities (above 12 to 15 ppth) can create conditions favorable to the spread of the infection. This is captured below, under the rankings for biological stressors.

Sedimentation displays a north-south trend of increasing intensity, with greatest deposition observed in Zones 5 and 6, and least in Zones 2 and 3. This pattern is linked largely to flow and overall energy of the system.

5.2.2 Chemical Stressors

Chemical concentrations in environmental media and estimated chemical loadings were used to assess stressor strength across the Estuary for all chemicals.

Most of the chemical stressors represent chemical groups rather than individual chemicals. In these instances, we used information on a subset of all chemicals within the group to assess trends. This was most often because more monitoring data were available for these subsets of chemicals. For example, trends of petroleum, PAHs, and related compounds were based on total PAH data. PCBs were largely based on total PCBs, though the source loading estimates developed by DRBC were based on penta-PCB data. Pesticide trends were based on the chlorinated pesticide DDx (i.e., total DDT, DDD, and DDE compounds) because we had the most regional data for this pesticide. Chlordane trends were not separately evaluated given the paucity of data, but generally tracked the DDx trends in the one study that provided data on both

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(Hartwell et al., 2001). Data for other pesticides were sparse but did not suggest they were important stressors in the River. Metal trends were characterized based on evaluation of multiple metals, as published by others. Mercury-specific trends were not separately ranked because the available data do not present a consistent spatial pattern. Sediment data from Frithsen et al. (1995) indicate that the concentration of total mercury in sediment is relatively consistent in Zones 3 through 5 and lowest in Zones 2 and 6. Conversely, seasonal water data collected by Reinfelder and Totten (2006) suggest that mercury levels in Zone 5 and 6 are higher than other areas, although the high sampling variability limits the certainty of these findings. More data are needed to better assess mercury spatial trends.

With the exception of dissolved oxygen, all chemical stressors display a north-south trend of decreasing strength. Chemical stressor magnitude is consistently ranked as high in DRBC Zones 2 and 3. Zones 4 and 5 represent transitional zones for most chemical stressors. Chemical stressor strength in Zone 6 is consistently ranked as low. This north-south trend is consistent with our expectation that urban and industrial areas of the northern Estuary will be an important source of many of these chemicals.

5.2.3 Biological Stressors

Some information was available to rank the magnitude of biological stressors due to reduction in local stocks as well as to pathogens that cause oyster disease.

Overall, reduction in local stocks due to fishing pressure was judged to be a medium-level stressor throughout the Estuary, largely because it has been of historical importance for some species. Though current fishery management plans are in place to ensure that fishing pressure does not result in significantly lower fish or shellfish populations, we did not identify sufficient data to document that was the case. The magnitude of reductions in local stocks due to impingement and entrainment of fish and other aquatic life was estimated based on total water withdrawal by zone as summarized in Santoro (2004) and USEPA (2002).

Pathogens associated with oyster disease MSX and Dermo have severely impacted the oyster population in the Delaware Bay (Zone 6), and Dermo is currently a limiting factor on oyster production in the Estuary. These pathogens exist in saline waters generally greater than 10–12 ppth. Their known effects are limited in Zone 6, where significant oyster populations historically existed. No significant oyster populations exist outside of this zone and therefore the stressor is considered absent in the other zones. We did not locate data suggesting that any other pathogens are adversely affecting the ecological health of the Estuary.

Insufficient data were available to gauge the stressor strength of invasive species. Though we know that the number of invasive species in the system is on the rise in each of the states bordering the Estuary, we do not have sufficient information to understand the distribution and prevalence of these invasive species. We do have information on the distribution of Phragmites-dominated wetlands along the DE shoreline, and based on this, we know that this stressor occurs at a greater strength in Zone 5 compared to Zone 6 in DE. We did not locate information on Phragmites-dominated wetlands in other portions of the Estuary, however.

5.3 Key Data / Information Gaps and Uncertainties

The rankings presented here should be considered preliminary. They represent our current best interpretation of the available data, but are limited in their certainty by gaps in knowledge about the presence, distribution, and magnitude of stressors and their interactions. We currently lack sufficient information to even construct a preliminary ranking for a number of the regional

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stressors. Even the information that we do have is limited in many instances because we do not have a sufficiently and statistically robust data set, we do not have all areas of the Estuary represented or represented equally, we have information for only a subset of all potential stressors within the category (e.g., pesticides), and/or we have information that was collected nearly a decade or more in the past. In addition, a substantial amount of monitoring effort has been focused on chemical contaminants and relatively fewer studies area available on physical and biological stressors. Furthermore, some stressors interact with each other and the full nature of those interactions is not completely understood.

Key uncertainties and data / information influencing our understanding of stressor distribution in the Estuary include the following:

� Hydrodynamic interactions across stressors. The role of water volume, salinity, temperature, suspended sediment, and sedimentation are all important factors in defining the physical environment within the Estuary and its consequent significance. Kreeger et al. (2006) called for the development of an updated hydrodynamic model for the entire Estuary that could help to explain the actions and interactions of all components of the system. Such a model could potentially add to the strength of our understanding of these complex interactions on both regional and local scales, which could result in a thorough examination of the interactions between stressors.

� Habitat. Dams and weirs create physical obstructions to spawning runs of anadromous fish such as American shad, blueback herring, alewife, and other species. Historical declines in some species were partly linked to loss of access to spawning habitat. Additional data, or a synthesis of existing data, are needed to better characterize the magnitude and distribution of this stressor in the Estuary.

� Chemical monitoring data. Though a significant amount of historical monitoring has been conducted in the Estuary, too few data currently exist to define with great certainty the magnitude and distribution of constituents. Of greatest need are adequate monitoring data for sediments and biological tissue, because water column contaminants do not appear to be a significant source of impairment Estuary-wide. A data set published by Hartwell et al. (2001) based on the results of 1997 sampling provides the most comprehensive data for sediments, but the study did not sample for all potential chemical stressors. Furthermore, it is nearly a decade old, so its representation of current conditions is unknown. Even fewer region-wide data are available for fish or other biological tissue. The most comprehensive recently published data set for fish tissues was generated by Ashley et al. (2004), but it addressed only PCBs. Few data also exist on the distribution and extent of dioxins/furans in the Estuary. We did not independently compile data from individual databases, however, and these are a source of additional monitoring data. A comprehensive compilation of existing site-specific and regional data sets of chemical monitoring data would be a beneficial step in gaining a more comprehensive understanding of temporal and spatial trends of chemical stressors. This, however, was beyond the scope of the current task.

� Reductions in local stocks. Too few data are available to assess the degree to which local stocks are reduced due to fishing pressure. Additional catch-independent assessments of fish populations would provide a more unbiased assessment of harvesting pressure. Some of these data might already exist, but have not yet been synthesized

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and/or published. Estuary-wide data on impingement and entrainment and trophic models would be helpful in evaluating the magnitude and consequence of this stressor.

� Invasive species. Invasive species occur throughout the Estuary, but comprehensive data are lacking on the rate and spatial extent of invasive species introductions to the Estuary. Also, few measures are available to understand how these species affect the Estuary ecosystem. The recent data on the distribution of Phragmites wetlands on coastal DE does provide a good summary of the distribution of that stressor in that area of the Estuary. Similar data for the NJ shoreline was not found, however.

� Pathogens. The ecological consequence (e.g., intertidal and infaunal production), if any, of the loss of shellfish beds due to oyster disease is not known.

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6. Summary and Conclusions

This report has been prepared as part of an ongoing Delaware River Study that was initiated by DuPont in 2005. The focus of this investigation was to compile and evaluate information on the type, magnitude, and distribution of stressors that have likely influenced ecological conditions in the River historically and that are now possibly influencing current conditions. Information on stressors presented in this report will be integrated into an overall regional risk assessment designed to characterize, rank, and determine the key stressors that are most significantly influencing the current ecological conditions in the Delaware Estuary.

There is a large body of knowledge and information that exists for the Estuary (both current and historical), including a number of summary reports and bibliographies that have been created. Our report builds upon this collective synthesis information and updates it with more recent data when available. We focus on synthesis of readily available literature rather than new evaluations of raw data. We also focus on regional data sets that will support the regional review of ecological conditions. We understand that there are significant site-specific data sets that have been developed to satisfy operational and regulatory requirements at individual facilities throughout the Estuary, but this level of data collection and synthesis was beyond the scope of our effort.

The collective evaluation has shown that a multitude of physical, chemical, and biological stressors exist in the Estuary and that these stressors emanate from a variety of sources. These sources include urban and agricultural land use and related development, industrial facilities, electric generating facilities, maritime operations, dredging and related activities, discharges from municipal WWTPs, CSOs, and stormwater, accidental spills and releases, recreational boating, fishing and fisheries management, sediments, and atmospheric deposition.

From a historical perspective, many of the ecological stressors of most significance have their roots in the urbanization and industrialization of the Estuary. During the more than 300 years of development, habitat loss was severe as wetlands and streams were filled, shorelines were altered, uplands were cleared, and the invasive exotic wetland plant Phragmites australis took a foothold in the disturbed wetland areas of the region. Water quality also suffered from the outset of development, but declined precipitously in the early-to mid-20th century, due to the increased impact of population growth and expanding industrialization. Dissolved oxygen deficits stemming from the release of heavy loads of oxygen-demanding wastes from both industrial and municipal sources posed some of the more identifiable water quality problems during that time. In-water activities also greatly impacted the quality and character of the Estuary habitat and community. Water balance was affected as an increasingly large populace and industrial sector withdrew and consumed larger amounts of water from the Estuary and its tributaries. Navigational dredging, which began in the late 19th century, changed the character of the Estuary bottom, increased water volume and tidal flow and facilitated upstream transport of saltwater. Heavy harvest from the fishery along with placement of dams in the tributaries contributed to declines in many of the Estuary’s sport and commercial fish.

The magnitude of some of these stressors has lessened in more contemporary times. Water quality improved with the advent of pollution control programs starting principally in the late 1950s and early 1960s. Wetland and other habitat loss, though still continuing, have slowed significantly compared to earlier days of development. In addition, fishery management programs along with habitat restoration have been put in place to help restore important commercial and recreational species.

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Other stressors to the Estuary have held steady or are increasing. Water withdrawal and consumption continue to increase, dredging continues on an ongoing basis, and nutrient loads continue to be some of the highest across all estuaries in the U.S.

Still others had their origin in more recent times or are only beginning their influence. The oyster disease MSX entered the Estuary in the late 1950s and quickly decimated the Estuary’s oyster population. A second oyster disease, Dermo, which also entered the Estuary in the 1950s, decimated the oyster populations in the 1990s and continues to do so today. Sea level rise coincident with global warming is predicted by many researchers to be a potentially significant stressor in this century.

Under present day conditions, historical habitat loss continues to define the character of the Estuary shoreline even though the rate of habitat loss has declined in recent times. Despite the fact that some restoration efforts have taken place, the total habitat restored is but a small portion of the original habitat that was lost or altered over time. Much of the habitat that does remain is altered or otherwise disturbed.

Water consumption places a continuing demand on freshwater inputs to the Estuary, which, in turn, can affect salinity and temperature, or increase tidal amplitudes, which ultimately can cause bank erosion and change wetland hydrological characteristics. Navigational dredging continues to change the character of the Estuary bottom and increase water volume and tidal flow, which facilitates upstream transport of saltwater and can lead to shoreline erosion. Sea level rise, though not yet measurably affecting the Estuary’s ecological habitats and communities, could do so in the future as wetlands are flooded, shoreline position is shifted, and saltwater migrates up the Estuary.

Chemical stressors continue to play a role in the current day stressor mix of the Estuary, though the media of interest appear to have shifted from the water column to sediments and the food web. Though once documented as significant, contaminants in the water column under present day conditions appear to be less so. The widespread and significant problems with dissolved oxygen are now reduced to more localized areas. Trace metals concentrations in the water are less than those of other northeastern U.S. estuaries, and metal contamination of the water column appears to be localized near tributaries or other specific locales. Nutrient levels continue to be high, but the ecological implications of this appear to be mitigated by the presence of a high suspended solid load, which reduces light penetration and thus the potential for eutrophication. The presence of other chemical stressors in the water column is still under investigation, but toxicity tests demonstrated a lack of surface water toxicity. The magnitude and significance of chemical stressors in the Estuary’s sediments and food web has not been fully determined, but continues to be the subject of increasing interest by regulators, the regulated community, and the public.

Biological stressors continue to be important in defining ecological conditions in the Estuary. The oyster disease Dermo continues to be the dominant force in oyster mortality and has reached the epizootic scale during the present day. The influence of other biological stressors, though possible, is not well known.

The most recent data show that these collective stressors are distributed throughout the Estuary, but at varying magnitude. Data on relative stressor magnitude were used to develop relative rankings of stressors throughout different regions of the Estuary. Adequate data were available to develop some preliminary rankings of the spatial distribution of most physical and chemical

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stressors, and some biological stressors. Additional information is needed to refine these preliminary rankings and to develop rankings for stressors for which current data are not adequate.

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Walsh, D.R. 2004. Anthropogenic Influences of the Morphology of the Tidal Delaware River and Estuary: 1877-1987. Thesis. University of Delaware, Newark, DE.

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Weisberg, S.B., P. Himchak, T. Baum, H.T. Wilson, and R. Allen. 1996. Temporal trends in the abundance of fish in the tidal Delaware River. Estuaries 19(3):723-729.

Wetlands Research Associates, Inc. 1995. Tidal Wetlands Characterization - Then and Now: Final Report. Delaware Estuary Program: DELEP Report #95-01. Prepared for the Delaware River Basin Commission.

Whitmore, W. 2005. Marine Recreational Fishing in Delaware 2004. Dover, DE: Delaware Department of Natural Resources and Environmental Control.

Wonham, M.J., J.T. Carlton, G.M. Ruiz, and L.D. Smith. 2000. Fish and Ships: Relating Dispersal Frequency to Success in Biological Invasions. Marine Biology 136:1111-1121.

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Tables

Page 104: Characterization of Ecological Stressors in the Delaware Estuary

Search Method Location

Dialog http://www.dialog.com

OCLC FirstSearch http://firstsearch.oclc.org

Toxicology Literature Online (TOXLINE) http://toxnet.nlm.nih.gov/

Atlantic States Marine Fisheries Commission http://www.asmfc.org

City of Philadelphia http://www.phila.gov

Coastal America http://www.coastalamerica.gov

Delaware Department of Natural Resources and Environmental Control http://www.dnrec.state.de.us

Delaware River & Bay Authority http://drba.net

Delaware River Basin Commission http://www.state.nj.us/drbc

Delaware River Port Authority http://www.drpa.org

Delaware Valley Regional Planning Commission http://www.dvrps.org

National Oceanic & Atmospheric Administration http://www.noaa.gov

NJ Department of Environmental Protection http://www.state.nj.us/dep

Partnership for the Delaware Estuary http://www.delawareestuary.org

Pennsylvania Department of Conservation & Natural Resources http://www.dcnr.state.pa.us

Pennsylvania Department of Environmental Protection http://www.dep.state.pa.us

Pennsylvania Fish & Boat Commission http://www.fish.state.pa.us

Philadelphia Port Authority http://www.philaport.com

The Port Authority of New York & New Jersey http://www.panynj.gov

U.S. Army Corps of Engineers http://www.usace.army.mil

U.S. Coast Guard http://www.uscg.mil

U.S. Department of Agriculture http://www.nrcs.usda.gov

U.S. Environmental Protection Agency http://www.epa.gov

U.S. Fish & Wildlife Service http://www.fws.gov

U.S. Geological Survey http://www.usgs.gov

National Oceanic & Atmospheric Administration, National Centers for Coastal Ocean Science

National Status and Trends Program (NS&T): Monitoring Data http://ccma.nos.noaa.gov/stressors/pollution/nsandt/welcome.html

U.S. Coast Guard

Spill Response Database http://old.incidentnews.gov/incidents/history.htm

U.S. Department of Agriculture

Invasive Species Database http://www.invasivespeciesinfo.gov/

U.S. Department of Transportation

Maritime Administration - Data & Statistics http://www.marad.dot.gov/MARAD_statistics/index.html

U.S. Environmental Protection Agency

Electronic-Facility Data Release (E-FDR) Database http://www.epa.gov/tri-efdr/

EMAP Database http://www.epa.gov/emap/nca/html/data/index.html

Enforcement & Compliance History Online (ECHO) http://www.epa.gov/echo

Enviromapper http://www.epa.gov/enviro/html/em/

STORET Legacy Data Center Database http://www.epa.gov/storpubl/legacy/query.htm

STORET Data Warehouse Database www.epa.gov/STORET/dw_home.html

Toxics Release Inventory (TRI) Explorer Database http://www.epa.gov/triexplorer/

U.S. Fish and Wildlife Service

National Wetlands Inventory http://wetlandsfws.er.usgs.gov/NWI/index.html

U.S. Geological Survey

National Water Information System Web Site (NWISWeb) http://waterdata.usgs.gov/nwis

National Water-Quality Assessment (NAWQA) Program: Delaware River Basin (DELR) Study Unit http://nj.usgs.gov/nawqa/delr/

Nonindigenous Aquatic Species (NAS) Database http://nas.er.usgs.gov/

WaterWatch http://water.usgs.gov/waterwatch

Academy of Natural Sciences http://www.acnatsci.org

America Fisheries Society http://fisheries.org

Delaware Audubon Society http://www.delawareaudubon.org

Delaware Nature Society http://delawarenaturesociety.org

Delaware Riverkeeper Network http://www.delawareriverkeeper.org

Drexel University http://www.drexel.edu

Heritage Conservancy http://www.heritageconservancy.org

Historical Society of Delaware http://www.hsd.org

Historical Society of Pennsylvania http://www.hsp.org

National Shellfisheries Association http://shellfish.org

New Jersey Academy of Science http://www.njas.org

New Jersey Audubon Society http://www.njaudubon.org

New Jersey Conservation Foundation http://www.njconservation.org

TABLE 2-1

INTERNET SITES SEARCHED - Regulatory Agencies & Governmental Organizations, SPECIFIC DATABASES

INTERNET SITES SEARCHED - Non-Governmental Organizations & Research Institutions, GENERAL

ONLINE LITERATURE SERVICES

INTERNET SITES SEARCHED - Regulatory Agencies & Governmental Organizations, GENERAL

RESOURCES FOR DATA AND INFORMATION SEARCH

DRAFTTable 2-1 Page 1 of 2

Page 105: Characterization of Ecological Stressors in the Delaware Estuary

Search Method Location

TABLE 2-1

RESOURCES FOR DATA AND INFORMATION SEARCH

New Jersey Historical Society http://www.jerseyhistory.org

New Jersey Marine Science Consortium http://www.njmsc.org

New Jersey Water Resources Institute http://njwrri.rutgers.edu

Pennsylvania Audubon Society http://pa.audubon.org

Pennsylvania Environmental Council http://www.pecpa.org

Pennsylvania Organization for Watersheds & Rivers http://www.pawatersheds.org

Rutgers University http://www.rutgers.edu

Sierra Club http://www.sierraclub.org

The Nature Conservancy http://nature.org

University of Delaware http://www.udel.edu

University of Pennsylvania http://www.upenn.edu

Water Resources Association of the Delaware River Basin http://www.wradrb.org

Wildlife Management Institute http://www.wildlifemanagementinstitute.org

Woods Hole Oceanographic Institute http://www.whoi.edu

INTERNET SITES SEARCHED - Non-Governmental Organizations & Research Institutions, SPECIFIC DATABASES

Invasive Species Specialist Group (ISSG)

Global Invasive Species Database http://www.invasivespecies.net/database/welcome/

OMB Watch

The Right-to-Know Network (RTKNet) http://www.rtknet.org/rtkdata.php

Smithsonian Environmental Research Center (SERC)

National Exotic Marine and Estuarine Species Information System (NEMESIS) Database http://invasions.si.edu/nemesis/index.htmlLIBRARIES VISITED OR SEARCHED

Delaware River Basin Commission West Trenton, NJ

Drexel University http://www.library.drexel.edu/

Rutgers University Piscataway, Camden, & New Brunswick, NJ

The Free Library of Philadelphia http://www.library.phila.gov

Trenton Public Library http://www.trenton.lib.nj.us

University of Delaware Newark, DE

University of Maryland College Park, MD

Wilmington Public Library www.wilmlib.org/

Delaware Department of Natural Resources and Environmental Control Dover, DE

Delaware River Basin Commission West Trenton, NJ

National Oceanic & Atmospheric Administration Philadelphia, PA

New Jersey Department of Environmental Protection Trenton, NJ

Partnership for the Delaware Estuary Wilmington, DE

Pennsylvania Department of Environmental Protection Norristown, PA

U.S. Fish & Wildlife Service Tobyhanna, PA

U.S. Environmental Protection Agency Philadelphia, PA

REGULATORY AGENCIES & GOVERNMENTAL ORGANIZATIONS VISITED OR CONTACTED

DRAFTTable 2-1 Page 2 of 2

Page 106: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 2-2DIALOG DATABASES SEARCHED

Database

INSPEC WasteInfoBiosis Previews(R) Water Resources Abstracts

NTIS ICONDA-Intl ConstructionEi Compendex(R) Earthquake Engineering Abstracts

AGRICOLA Biol. & Agric. IndexCSA Life Sciences Abstracts Pascal

Oceanic Abstracts MEDLINE(R)Meteorology & Geoastrophysical Abstracts ToxFile

SciSearch(R) Global HealthDissertation Abs Online EMBASE Alert

Enviroline(R) Pharm-line(R)Pollution Abstracts Adverse Reaction Database

Aquatic Science & Fisheries Abstracts AGRISPAIS Int. Drug Info. Fulltext

CAB Abstracts WATERNET(TM)Food Sci.&Tech.Abs FEDRIP

FOODLINE(R): Science GEOBASE(TM)GeoArchive Pesticide Fact File

FOODLINE(R): Legal DOSEANTE: Abstracts in New Tech & Engineer Chemical Safety NewsBase

Civil Engineering Abstracts Material Safety Data SheetsSPIN(R) Material Safety Summary Sheets

Environmental Engineering Abstracts RTECSInside Conferences CHEMTOX (R) Online

SEDBASE Ei EnCompassLit(TM)EMBASE New Scientist

Int.Pharm.Abs ScienceEnvironmental Sciences Beilstein AbstractsTULSA (Petroleum Abs) CA SEARCH(R)

GeoRef Adis Newsletters(Current)JICST-EPlus Adis Newsletters(Archive)

FLUIDEX SciSearch(R) Cited Ref Sci_1974-1989General Sci Abs New England Journal of Med.

Wilson Appl. Sci & Tech Abs USP DI(R) VOL. I_2005Energy SciTec McGraw-Hill Publications

AESIS

DRAFTTable 2-2 Page 1 of 1

Page 107: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 2-3 COMPONENTS OF ELECTRONIC BIBLIOGRAPHY

Primary Components Subject Categories Availability

Number (Identifier) Surface Water Electronic CopyReference - author/year Sediment Electronic Raw Data Available

Reference - bibliographical format Toxicology Available Online for DownloadDescription Bioaccumulation Website or CD Availability of Data or Report

HabitatBiological Communities

WetlandsHydrodynamics

Dredging/BridgesEconomics/Socioeconomics

SourcesHuman Use

Air Quality, Meteorology, GeologyChemical/Effluent Releases

Historical

DRAFTTable 2-3 Page 1 of 1

Page 108: Characterization of Ecological Stressors in the Delaware Estuary

River RiverMile Kilometer(RM) (KM)

Cape Henlopen, Tip 0 0 6

Downstream Limit of Zone 5 48.2 77.55 5

Downstream Limit of Zone 4 78.8 126.79 4

Downstream Limit of Zone 3 95 152.86 3

Downstream Limit of Zone 2 108.4 174.42 2

Downstream Limit of Zone 1 133.4 214.64 1E

Sources:

Note:

Feature

Delaware River Stream Mileage System. http://www.state.nj.us/drbc/mileage.htm.

DRBCWater Quality

Zone

DRBC ZONES AND MILE CONVERSIONS FOR THE DELAWARE RIVERTABLE 2-4

Zone 1 is the non-tidal Delaware River above Trenton, NJ and is not part of the Estuary

Table 2-4 Page 1 of 1

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Page 110: Characterization of Ecological Stressors in the Delaware Estuary

SourceDistance

(km)

Drainage Area

(km2)

Average Annual Flow

(ft3/s)

Delaware River at Trenton 210 17,560 11,280Intermediate small tributaries No Data 13,367 1,800Schuylkill River at Philadelphia 150 4,944 2,750Intermediate small tributaries No Data 1,202 650Christina-Brandywine near Wilmington 110 1,475 750Intermediate small tributaries No Data 4,514 2,240Total at Mouth 0 33,062 19,470

Source:Smullen et al. (1984), as presented in Sutton et al. (1996)

Notes:km = kilometers

km2 = square kilomters

ft3/s = cubic feet per second

TABLE 4-1FRESHWATER FLOW OF THE DELAWARE ESTUARY

DRAFTTable 4-1 Page 1 of 1

Page 111: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-2 CHRONOLOGY OF MAJOR AND OTHER NOTABLE FLOODS AND DROUGHTS

IN DELAWARE, 1846–1989

Floodor

DroughtDate Area Affected

RecurrenceInterval(years)

Remarks

Flood Oct. 13, 1846Lower Delaware

RiverUnknown

"Great Hurricane of 1846." Severe storm-surge flooding nearNew Castle

Drought 1930–1934 Statewide UnknownMost extensive drought since 1894 in humid parts of United States

Flood Aug. 23, 1933Coastal parts of

DelawareUnknown Severe tidal flooding and widespread damage to resort areas

Flood May 1, 1947Christina River

basin25 to 50

Record rainfall intensity. Until exceeded in 1989, this was the largest discharge recorded since April 1943 on Christina River at Coochs Bridge

Drought 1953–57 Statewide 10 to 25 Agricultural operations affected substantially

FloodAug. 18–19,

1955

Christina River, White Clay, Red

Clay, and Brandywine Creek

basins

25 to 50

Hurricanes Connie (Aug. 12–13, 1955) and Diane (Aug. 18–19, 1955). Many lives lost and extensive property damage

FloodSept. 12–13,

1960Statewide 10 to >50

Hurricane Donna. Largest discharge recorded since January 1958 on St. Jones River at Dover

Flood Mar. 1962Coastal parts of

Delaware>2 Record high tide at Lewes. Severe storm-surge flooding

Drought 1967–71 Statewide 10 to >25Longest and most severe drought in Northeastern United States

Flood Aug 3–27, 1967 Statewide 25 to 50Record monthly rainfall at Bridgeville. In central Delaware, 3 lives lost and extensive property damage

Flood June 22, 1972

Christina River, Blackbird Creek,

BrandywineCreek, and

Smyrna River basins

10 to >50

Hurricane Agnes. Greatest flooding and damage in adjacent Middle Atlantic States

FloodFeb. 25–26,

1979SouthernDelaware

25 to >50 Intense rain on about 20 inches of snow cover. Lives lost, 1

Drought 1979–83 Statewide 10 to 25 Decreased crop yields. Water rationing in effect

Drought 1984–88 Statewide 10 to 25Decreased crop yields. Temporary restrictions on nonessential water use in northern Delaware

Flood July 5, 1989

Christina River, White Clay, Red

Clay, and Shellpot Creek basins

>100

Tropical Storm Allison. Lives lost, 3. Property damage, $5 million

Source:USGS (No Date)

DRAFTTable 4-2 Page 1 of 1

Page 112: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-3 DELAWARE RIVER AVERAGE DISCHARGE

AT TRENTON, 1954–1981

Monthly Averages m3/s

January 338February 366

March 545April 603May 381June 246July 172

August 177September 162

October 219November 282December 352

Seasonal Averages m3/s

Winter (Nov–Feb) 334Spring (Mar–May) 510

Summer (June–Oct) 195

Annual Average m3/s

Oct–Sept 320

Source:Hires et al. (1984), as presented in Sutton et al. (1996)

Note:

m3/s = cubic meters per second

DRAFTTable 4-3 Page 1 of 1

Page 113: Characterization of Ecological Stressors in the Delaware Estuary

Year Project/ Location Depth/ Width Volume Source

Early 1800sMost dredging performed in Harbors:

New Castle, Wilmington, Chester, Marcus Hook

Natural Delaware River depth of 12 to 27 ft was adequate for vessels of

this time

Snyder and Guss, 1974

USACE, No Date

Snyder and Guss, 1974

1829–1830 Delaware River HarborsKnown example of this

dredge excavated a 10 ft channel

15,369 cy Snyder and Guss, 1974

1832 Port Penn Snyder and Guss, 19741833 Marcus Hook Snyder and Guss, 1974

1835 Snyder and Guss, 1974

1840s–early1850s

Snyder and Guss, 1974

1853

Atlantic Division recommended a system of navigation improvements

for national defense—not necessarily concentrated in Delaware River

Region

Snyder and Guss, 1974

1870s Snyder and Guss, 1974

Delaware River between Bordenton, NJ (sandbar at entrance to Raritan

Canal) to Duck Creek, DE

Duck Creek entrance dredged to 8 ft

Cherry Island Flats (opposite mouth of Christina River)

1.5 mcy from channel

Bulkhead Shoal at river curve below New Castle, DE

24 ft channel on a 1 mile axis

Petty’s Island/ Mifflin Bar

1878Typical vessel draft using Delaware

River is 20–24 ftSnyder and Guss, 1974

Schooner Ledge—rock reef located 18 mi south of Philadelphia

24 ft MLW

Dredged material disposal experiment at Ft. Mifflin

Board appointed to make recommendations for future

Delaware River improvements

Recommended that 27–28 ft was the greatest depth that could be maintained, and that was sufficient as typical vessel draft was

approximately 25 ft

1877–1882 Snyder and Guss, 1974

1879 Snyder and Guss, 1974

USACE Colonel recommended extending harbor piers into natural channels to limit need for dredging

Sporadic harbor dredging, but Delaware River had sufficient natural depth to accommodate vessel draft

Philadelphia becomes 2nd largest national port and the Delaware River is used for international shipping

TABLE 4-4 DREDGING HISTORY OF THE DELAWARE ESTUARY

1804Philadelphia Harbor, Schuylkill River,

and Delaware RiverChannel Deepening

3,467,000 cy dredged prior to 1885

DRAFTTable 4-4 Page 1 of 3

Page 114: Characterization of Ecological Stressors in the Delaware Estuary

Year Project/ Location Depth/ Width Volume Source

TABLE 4-4 DREDGING HISTORY OF THE DELAWARE ESTUARY

1890–1896 Philadelphia Harbor area10.7 mcy (for river

disposal)Snyder and Guss, 1974

1968–1980 average annual maintenance

=1.1 mcy

No additional dredging required after 1980

Philadelphia (Christian St.) to Delaware Bay (Bombay Hook)

Authorization, 56 miles30 ft channel

34,953,000 cy of sediment plus 24,000 cy of rock—this is part of the 51,470,000 cy new work 1886–1909

referred to in 1885

USACE, No Date; Snyder and Guss, 1974

1900 Artificial Island—construction begins Snyder and Guss, 1974

1900–1930 Dredge Material DisposalWetlands Research Associates,

19951901–1904 Snyder and Guss, 1974

1910–1930 Dredged Material DisposalWetlands Research Associates,

19954,054,000 new work

1968–1980 annual average maintenance

=220,000 cy

Delaware River at Camden Authorization—

Total of 4 miles long

Newton Creek/ Kraighn Point to Berkley Street Terminal

30 ft deep

Kraighn Point to Cooper Point 18 ft deep

Camden Marine Terminal 37 ft deep

1919

This project has natural depths greater than authorization—so it

only needs occasional spot dredging

USACE, 1984

USACE, No Date, 1950, 1984, 1992

1917–present

Schuylkill River Authorization—confluence with

Delaware River to University Avenue

22 ft to 33 ft depth, total of 6 miles long

USACE, No Date, 1984

1910

Philadelphia to the Sea project Authorization—from Philadelphia to Delaware Bay—includes dredging of

5 anchorages: Mantua Creek, Marcus Hook, Port Richmond, Deepwater Point, Reedy Point

35 ft deep channel, 400 ft wide in Philadelphia to

1,000 ft wide in Bay

49,424,000 cy new work

USACE, 1950

1896

Wilmington Harbor Channel Authorization—Christina River

channel from Delaware River with turning basin at Wilmington Marine

Terminal

Depths included 35 ft, 21 ft, 10 ft, and 7 ft sections,

Total of 9 miles longUSACE, 1984; USACE, 1992

1885–1898 Philadelphia to Delaware Bay 26 ft channel depth51,470,000 cy new work 1886–1909

DRAFTTable 4-4 Page 2 of 3

Page 115: Characterization of Ecological Stressors in the Delaware Estuary

Year Project/ Location Depth/ Width Volume Source

TABLE 4-4 DREDGING HISTORY OF THE DELAWARE ESTUARY

1920 Dredge Material DisposalWetlands Research Associates,

1995

Philadelphia to Trenton Authorization—

Total of 30.5 miles long1968–1980 average annual=550,000 cy

36,345,000 cy new work (1957–1964)

14,572,000 cy maintenance(1914–1967)

Newbold Island to Trenton Marine Terminal

35 ft deep

Trenton Marine Terminal to Penn Central Railroad

12 ft deep

42,048,005 cy2,378,852 cy

499,833

1942–1943Philadelphia Navy Yard to Delaware

Bay maintenance29 mcy of sediment

plus 121,000 cy of rockSnyder and Guss, 1974

1946 Dredge Material DisposalWetlands Research Associates,

1995

Notes:

ft = feetcy = cubic yardsmcy = million cubic yardsMLW = mean low water

USACE, No Date, 1950, 1984, 1992

1992–present

Investigation of Philadelphia to Sea proposed deepening—project

evaluation is ongoing

45 ft channel deepening from 40 ft proposed

53,523,300 (for channel and berth

area)

1968–1992

Continued Maintenance of Philadelphia to the Sea—from

Philadelphia to Delaware Bay—includes dredging of 5

anchorages

Deepen channel to 40, 400 ft wide in Philadelphia to

1,000 ft wide in Bay

1968–1980 average annual maintenance =

7,980,000 cy (5.4 mcy average as of

1992)

USACE, 1992, 1997

USACE, No Date, 1950, 1984, 1992

1940–1942Philadelphia Navy Yard to Delaware Bay (Part of 1938–45 Phil. To Sea

project)40 ft channel Snyder and Guss, 1974

1938–1968

Philadelphia to the Sea—from Philadelphia to Delaware

Bay—includes dredging of 5 anchorages

Deepen channel to 40, 400 ft wide in Philadelphia to

1,000 ft wide in Bay

53,380,000 cy new work in main channel,

plus anchorages

1930–present

Allegheny Avenue, Philadelphia to Newbold Island

40 ft deepUSACE, No Date, 1984

DRAFTTable 4-4 Page 3 of 3

Page 116: Characterization of Ecological Stressors in the Delaware Estuary

23

45

6T

empe

ratu

re

Sha

ll no

t exc

eed

5°F

(2.

8°C

) ab

ove

the

aver

age

24-h

our

tem

pera

ture

gra

dien

t di

spla

yed

durin

g th

e 19

61–6

6 pe

riod,

or

a m

axim

um o

f 86°

F (

30°C

), w

hich

ever

is le

ssX

XX

Sha

ll no

t be

rais

ed a

bove

am

bien

t mor

e th

an: 1

) 4°

F (

2.2°

C)

durin

g S

epte

mbe

r th

roug

h M

ay, n

or 2

) 1.

5°F

(0.

8°C

) du

ring

June

thro

ugh

Aug

ust

XX

The

max

imum

tem

pera

ture

s sh

all n

ot e

xcee

d 86

°F (

30.0

°C)

XT

he m

axim

um te

mpe

ratu

res

shal

l not

exc

eed

86°F

(30

.0°C

)X

Tot

al D

isso

lved

Sol

ids

Not

to e

xcee

d 13

3 pe

rcen

t of b

ackg

roun

d, o

r 50

0 m

g/L,

whi

chev

er is

less

XX

Not

to e

xcee

d 13

3 pe

rcen

t of b

ackg

roun

d X

Tur

bidi

tyU

nles

s ex

ceed

ed d

ue to

nat

ural

con

ditio

ns: m

axim

um 3

0 da

y av

erag

e 40

uni

ts,

max

imum

150

uni

tsX

XX

XX

Unl

ess

exce

eded

due

to n

atur

al c

ondi

tions

abo

ve R

M 1

17.8

1 du

ring

the

perio

d M

ay

30 to

Sep

tem

ber

15, m

axim

um 3

0 un

itsX

Thr

esho

ld O

dor

Num

ber—

Not

to e

xcee

d 24

uni

ts a

t 60°

CX

XX

XX

Sou

rce:

DR

BC

(20

04)

Not

es:

°C =

deg

rees

Cel

sius

°F =

deg

rees

Fah

renh

eit

mg/

L =

mill

igra

ms

per

liter

RM

= r

iver

mile

Zo

ne

TA

BL

E 4

-5D

RB

C P

HY

SIC

AL

PA

RA

ME

TE

R C

RIT

ER

IA F

OR

TH

E D

EL

AW

AR

E E

ST

UA

RY

Par

amet

er

DR

AF

TT

able

4-5

Pag

e 1

of 1

Page 117: Characterization of Ecological Stressors in the Delaware Estuary

(mgd) (%) (mgd) (%) (mgd) (%) (mgd) (%)

Power 5,059 68 57 20 5,878 69 93 9

Public 1,103 15 139 40 919 11 93 9

Industry 1,017 15 54 16 804 9 44 4

Agriculture 58 1 54 15 41 0.5 36 4

Other 46 1 30 9 147 2 19 2

NYC (export) - - - - 650 8 650 63

NJ (export) - - - - 90 1 90 9

Total 7,337 100 334 100 8,530 100 1,027 100

Source:Sutton et al. (1996)DRBC (2004)

Notes:mgd = million gallons per day% = percentData for 1990 do not include exports to New York City and New Jersey.DELEP (1989) estimates inflow to the Estuary to be 16,082 mgd.

TABLE 4–6WATER WITHDRAWAL AND CONSUMPTION FOR THE ENTIRE DELAWARE RIVER BASIN

Water Use Water Withdrawal (1990) Water Consumption (1990) Water Withdrawal (1996) Water Consumption (1996)

DRAFTTable 4-6 Page 1 of 1

Page 118: Characterization of Ecological Stressors in the Delaware Estuary

DRAFT Page 1 of 1Table 4-7

TABLE 4-7 ESTIMATED ANNUAL SEDIMENT BUDGET FOR THE DELAWARE ESTUARY,

ASSUMING A CLOSED SYSTEM

SourcesAmount

(x 103

tons)

Percentof Total Inputs

SinksAmount

(x 103

tons)

Percent of Total Sinks

Rivers—upland 2,000 68 Dredge spoil 3,300 78

Shore erosion 260 9 Marsh accumulation 935 22

Dredging leakage 175 6 Total 4,235

Sewer outfalls 121 4

Industrial effluents 52 2

Phytoplankton production

233 8

Atlantic Ocean NA

Airborne particulates 86 3

Total 2,927

Source:Biggs et al. (1983) as presented in Sharp (1983)

Page 119: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-8 FISH LADDER LOCATIONS IN NEW JERSEY AND DELAWARE AND HABITAT PROTECTED

Pond/Lake Location Date Installed Acres

Protected Stream Miles

Above Coursey Pond Frederica, DE 1996 58 2.70McColley Pond Frederica, DE 1996 49 21.15McGinnis Pond Frederica, DE 1996 31 11.81Silver Lake Dover, DE 1996 171 292.25Sunset Lake Bridgeton, NJ 1997 94 34.15Cooper River Camden, NJ 1998 190 2.36Evans Pond Camden, NJ 1999 25 6.58Garrison’s Lake Smyrna, DE 1999 86 8.03Moore’s Lake Dover, DE 1999 27 1.52Wallworth Lake Camden, NJ 1999 2 --Noxontown Lake Mildford, DE 2004 162 6.09Newton Lake Oaklyn, NJ 2004 41 2.03Silver Lake (upper dam) Mildford, DE 2004 27 2.15Silver Lake (lower dam) Mildford, DE 2004 -- --Steward Lake Woodbury, NJ 2004 38 5.34

Source:PSEG (2004)

Note:-- = estimate not provided

DRAFT Page 1 of 1Table 4-8

Page 120: Characterization of Ecological Stressors in the Delaware Estuary

TA

BL

E 4

-9

GE

NE

RA

L H

AB

ITA

T C

AT

EG

OR

IES

IN T

HE

DE

LA

WA

RE

ES

TU

AR

Y C

OM

PIL

ED

FR

OM

TH

E N

LC

D A

ND

ES

I MA

PS

Eco

log

ical

Hab

itat

Typ

eN

LC

D/E

SI L

and

Co

ver

Cat

ego

ries

Incl

ud

edN

ote

s/D

escr

ipti

on

Ben

thic

Sub

stra

tes

NA

Hab

itat a

crea

ge a

ssum

ed to

equ

al th

at o

f ope

n w

ater

are

a.

Inte

rtid

al M

udfla

ts &

San

dbar

s

Exp

osed

Tid

al F

lats

Bro

ad in

tert

idal

are

as c

ompo

sed

prim

arily

of s

and

and

min

or a

mou

nts

of s

hell

and

mud

She

ltere

d T

idal

Fla

tsA

reas

com

pose

d pr

imar

ily o

f silt

and

cla

y w

ith m

inor

am

ount

s of

san

d an

d sh

ell,

that

are

sh

elte

red

from

maj

or w

ave

activ

ity

Ope

n W

ater

Ope

n W

ater

Are

as o

f ope

n w

ater

, gen

eral

ly w

ith le

ss th

an 2

5% o

ther

land

cov

er

Wet

land

s

Woo

dy W

etla

nds

Are

as w

here

fore

st o

r sh

rubl

and

vege

tatio

n ac

coun

ts fo

r 25

-100

% o

f the

cov

er a

nd th

e so

il or

sub

stra

te is

per

iodi

cally

sat

urat

ed w

ith o

r co

vere

d w

ith w

ater

Em

erge

nt H

erba

ceou

s W

etla

nds

Are

as w

here

per

enni

al h

erba

ceou

s ve

geta

tion

acco

unts

for

75-1

00%

of t

he c

over

and

the

soil

or s

ubst

rate

is p

erio

dica

lly s

atur

ated

with

or

cove

red

with

wat

er

Imm

edia

tely

Adj

acen

t Upl

ands

Agr

icul

ture

Are

as c

hara

cter

ized

by

herb

aceo

us v

eget

atio

n th

at h

ave

been

pla

nts

are

inte

nsiv

ely

man

aged

for

the

prod

uctio

n of

food

, fee

d, o

r fib

er; o

r is

mai

ntai

ned

in d

evel

oped

set

tings

for

spec

ific

purp

oses

; her

bace

ous

vege

tatio

n ac

coun

ts fo

r 75

-100

per

cent

of t

he c

over

Nea

rsho

re U

plan

d F

ores

tA

reas

cha

ract

eriz

ed b

y tr

ee c

over

(na

tura

l or

sem

i-nat

ural

woo

dy v

eget

atio

n, g

ener

ally

gr

eate

r th

an 6

met

ers

tall)

; tre

e ca

nopy

acc

ount

s fo

r 25

-100

% o

f the

cov

er

Tra

nsiti

onal

Are

as o

f spa

rse

vege

tativ

e co

ver

(less

than

25%

) th

at a

re d

ynam

ical

ly c

hang

ing

from

one

la

nd c

over

to a

noth

er, o

ften

beca

use

of la

nd u

se a

ctiv

ities

; exa

mpl

es in

clud

e fo

rest

cl

earc

uts,

a tr

ansi

tion

phas

e be

twee

n fo

rest

and

agr

icul

tura

l lan

d, th

e te

mpo

rary

cle

arin

g of

ve

geta

tion,

and

cha

nges

due

to n

atur

al c

ause

s

Urb

an/R

ecre

atio

nal

Gra

sses

Veg

etat

ion

(prim

arily

gra

sses

) pl

ante

d in

dev

elop

ed s

ettin

gs fo

r re

crea

tion,

ero

sion

con

trol

, or

aes

thet

ic p

urpo

ses;

exa

mpl

es in

clud

e pa

rks,

law

ns, g

olf c

ours

es, a

irpor

t gra

sses

, and

in

dust

rial s

ite g

rass

es

Sou

rces

:U

SG

S (

1992

)

NO

AA

(20

02)

Not

es:

NLC

D =

Nat

iona

l Lan

d C

over

Dat

aset

ES

I = E

nviro

nmen

tal S

ensi

tivity

Inde

xN

A =

Not

App

licab

le

Tab

le 4

-9

Page 121: Characterization of Ecological Stressors in the Delaware Estuary

Mea

dow

Tid

al M

arsh

Riv

erin

eM

eado

wT

idal

Mar

shR

iver

ine

Mea

dow

Tid

al M

arsh

Riv

erin

eM

eado

wT

idal

Mar

shR

iver

ine

Mea

dow

Tid

al M

arsh

Riv

erin

eM

ead

owT

idal

Mar

shR

iver

ine

Sou

th P

hila

delp

hia

2,68

099

0

Tin

icum

Isla

nd80

050

015

060

Chr

istin

a R

iver

140

500

170

670

490

550

Woo

dbur

y/M

antu

a C

reek

s13

028

010

5575

230

Rac

coon

/Old

man

s C

reek

s15

1,13

51,

600

160

Red

Lio

n -

C&

D C

anal

290

830

7570

Kill

coho

ok/A

rtifi

cial

Isla

nd81

01,

520

590

Sou

rce:

Wet

land

s R

esea

rch

Ass

ocia

tes

(199

5)

Not

e :T

ime

perio

d is

from

the

late

180

0s to

199

5

TA

BL

E 4

-10

HIS

TO

RIC

WE

TL

AN

D F

ILL

AT

SP

EC

IFIC

SIT

ES

AL

ON

G T

HE

DE

LA

WA

RE

ES

TU

AR

Y (

AC

RE

S)

Riv

er L

oca

tio

nC

reat

ed O

pen

Wat

erC

reat

ed T

idal

Wet

lan

d L

oss

Wet

lan

d C

on

vers

ion

Dev

elo

pm

ent

Op

en W

ater

Hig

hw

ayD

red

gin

g

Tab

le 4

-10

Pag

e 1

of 1

Page 122: Characterization of Ecological Stressors in the Delaware Estuary

State River Location Historic AcreageWetland Loss

(Acres)Wetland Conversion

(Acres)

PennsylvaniaSouth Philadelphia (Camden and Philadelphia shores of the Delaware)

3,670 3,670

PennsylvaniaTinicum Island (downriver of League Island and south to the mouth of the Schuylkill)

1,510 1,510

Delaware Christina River 2,520 2,520New Jersey Woodbury/Mantua Creeks 780 780New Jersey Raccoon/Oldmans Creeks 2,910 2,910Delaware Red Lion - C&D Canal 1,265 1,195 70Delaware Killcohook/Artificial Island 2,920 2,330 590

Source:Wetlands Research Associates (1995)

Notes:Wetland loss consists of acres filled for development, open water, highway, or dredgingWetland conversion consists of created open water or created tidal areas

WETLAND LOSS AND CONVERSION AT SPECIFIC SITES ALONG THE DELAWARE ESTUARY TABLE 4-11

Table 4-11 Page 1 of 1

Page 123: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-12

TIDAL WETLAND LOSSES (ACRES) AND CAUSES BY STATE IN THE DELAWARE ESTUARY

Wetland Extent (Acres)Delaware New Jersey Pennsylvania

(1938–1973) (1953–1972) (1975–1986)

Acres in base year 80,148 111,066 1,640Acres in survey year 74,668 81,852 1,456Acres lost 5,730 29,214 184Cause of losses: Fills 2,315 5,941 184 Waterfowl impoundments 3,415 242 0 Mosquito impoundments 0 2,481 0 Muskrat impoundments 0 3,876 0 Agriculture 0 16,676 0

Source:Sullivan et al. (1991)

DRAFTTable 4-12

Page 1 of 1

Page 124: Characterization of Ecological Stressors in the Delaware Estuary

His

tori

cal

Cu

rren

tC

ou

nty

No

tes

Hop

e C

reek

Hop

e C

reek

Sal

em, N

J

Pea

chho

use

Ditc

hP

each

hous

e D

itch

New

Cas

tle, D

E

Ray

s D

itch

Ray

s D

itch

New

Cas

tle, D

E

Bla

ckbi

rd C

reek

Bla

ckbi

rd C

reek

New

Cas

tle, D

E

Unn

amed

Cre

ekS

alem

, NJ

Dis

conn

ecte

d fr

om s

ourc

e w

ater

, pos

sibl

y by

Art

ifici

al

Isla

nd fi

llA

ppoq

uini

min

k R

iver

App

oqui

nim

ink

Riv

erN

ew C

astle

, DE

Unn

amed

Cre

ekS

alem

, NJ

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

of A

rtifi

cial

Is

land

Unn

amed

Cre

ekLo

wer

Bre

akN

ew C

astle

, DE

Unn

amed

Cre

ekS

alem

, NJ

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

of A

rtifi

cial

Is

land

Unn

amed

Cre

ekU

pper

Bre

akN

ew C

astle

, DE

Silv

er C

reek

Silv

er R

unN

ew C

astle

, DE

Not

e na

me

chan

ge

Unn

amed

Cre

ekS

alem

, NJ

No

long

er p

rese

nt, p

roba

bly

due

to fi

lling

of A

rtifi

cial

Is

land

St.

Aug

ustin

e C

reek

Aug

ustin

e C

reek

New

Cas

tle, D

EN

ote

nam

e ch

ange

Allo

way

Cre

ekA

llow

ay C

reek

Sal

em, N

J

Unn

amed

Cre

ek/D

itch

Labe

led

"Str

aigh

t Ditc

h"S

alem

, NJ

Unn

amed

Cre

ekM

ill C

reek

Sal

em, N

J

St.

Geo

rges

Cre

ekS

t. G

eorg

es C

reek

New

Cas

tle, D

E

Sal

em C

reek

Sal

em R

iver

Sal

em, N

JN

ote

nam

e ch

ange

Bol

ls C

reek

Bal

drid

ge C

reek

Sal

em, N

JN

ote

nam

e ch

ange

Che

sape

ake

& D

elaw

are

Can

alC

hesa

peak

e &

Del

awar

e C

anal

New

Cas

tle, D

E

Mill

Cre

ekM

ill C

reek

/Goo

se P

ond

Sal

em, N

JP

ondi

ng a

t mou

th, p

ossi

bly

due

to h

ydro

logi

cal

alte

ratio

ns

Dra

gon

Cre

ekD

rago

n C

reek

New

Cas

tle, D

E

Unn

amed

Cre

ek/D

itch

Ced

ar C

reek

New

Cas

tle, D

E

Unn

amed

Cre

ekU

nnam

ed C

reek

Sal

em, N

J

Red

Lio

n C

reek

Red

Lio

n C

reek

New

Cas

tle, D

E

Tom

Cre

ekT

om C

reek

New

Cas

tle, D

E

Unn

amed

Cre

ekU

nnam

ed C

reek

Sal

em, N

JN

ow p

art o

f Kill

coho

ok N

atio

nal W

ildlif

e R

efug

e

Unn

amed

Cre

ekG

ambl

es G

utN

ew C

astle

, DE

Unn

amed

Cre

ekU

nnam

ed C

reek

New

Cas

tle, D

E

Unn

amed

Cre

ekM

iles

Cre

ekS

alem

, NJ

Not

e na

me

chan

ge

Mill

Cre

ekA

rmy

Cre

ekN

ew C

astle

, DE

Not

e na

me

chan

ge

Unn

amed

Cre

ekS

alem

, NJ

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

g

Unn

amed

Cre

ekS

alem

, NJ

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

g

Unn

amed

Cre

ekU

nnam

ed C

reek

New

Cas

tle, D

E

Unn

amed

Cre

ekU

nnam

ed C

reek

New

Cas

tle, D

E

Unn

amed

Cre

ekU

nnam

ed C

reek

New

Cas

tle, D

E

Sal

em C

anal

Sal

em C

anal

Sal

em, N

J

Unn

amed

Cre

ekS

alem

, NJ

Cut

-off/

redi

rect

ed a

t Riv

ervi

ew B

each

Unn

amed

Cre

ekM

agaz

ine

Ditc

hN

ew C

astle

, DE

TA

BL

E 4

-13

HIS

TO

RIC

AL

AN

D P

RE

SE

NT

–DA

Y T

RIB

UT

AR

IES

OF

TH

E D

EL

AW

AR

E E

ST

UA

RY

LIS

TE

D F

RO

M S

OU

TH

TO

NO

RT

H

DR

AF

TT

able

4-1

3P

age

1 of

3

Page 125: Characterization of Ecological Stressors in the Delaware Estuary

His

tori

cal

Cu

rren

tC

ou

nty

No

tes

TA

BL

E 4

-13

HIS

TO

RIC

AL

AN

D P

RE

SE

NT

–DA

Y T

RIB

UT

AR

IES

OF

TH

E D

EL

AW

AR

E E

ST

UA

RY

LIS

TE

D F

RO

M S

OU

TH

TO

NO

RT

H

Unn

amed

Cre

ekW

hoop

ing

John

Cre

ekS

alem

, NJ

Chr

istin

a R

iver

Chr

istin

a R

iver

New

Cas

tle, D

EN

ote

nam

e ch

ange

Bra

ndyw

ine

Riv

erB

rand

ywin

e R

iver

New

Cas

tle, D

E

Unn

amed

Cre

ekH

enby

Cre

ekS

alem

, NJ

She

llpot

Cre

ekS

hellp

ot C

reek

New

Cas

tle, D

EA

ltere

d, p

ossi

bly

re-r

oute

d un

derg

roun

d

Unn

amed

Cre

ekS

alem

, NJ

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

g

Unn

amed

Cre

ekS

alem

, NJ

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gU

nnam

ed C

reek

New

Cas

tle, D

EN

o lo

nger

pre

sent

, pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Unn

amed

Cre

ekS

tone

y C

reek

New

Cas

tle, D

EN

ote

nam

e ch

ange

Old

man

s C

reek

Old

man

s C

reek

Sal

em/G

louc

este

r, N

JU

nnam

ed C

reek

Unn

amed

Cre

ekN

ew C

astle

, DE

Unn

amed

Cre

ekN

ew C

astle

, DE

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gU

nnam

ed C

reek

New

Cas

tle, D

EN

o lo

nger

pre

sent

, pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Unn

amed

Cre

ekN

ew C

astle

, DE

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gU

nnam

ed C

reek

New

Cas

tle, D

EN

o lo

nger

pre

sent

, pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Unn

amed

Cre

ekN

ew C

astle

, DE

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gN

aam

an C

reek

Naa

man

Cre

ekN

ew C

astle

, DE

Unn

amed

Cre

ekB

irch

Cre

ekG

louc

este

r, N

JN

ote

nam

e ch

ange

Unn

amed

Cre

ekN

ew C

astle

, DE

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gM

arcu

s H

ook

Cre

ekM

arcu

s H

ook

Cre

ekD

elaw

are,

PA

Rac

coon

Cre

ekR

acco

on C

reek

Glo

uces

ter,

NJ

Unn

amed

Cre

ekS

tony

Cre

ekD

elaw

are,

PA

Not

e na

me

chan

geU

nnam

ed C

reek

Del

awar

e, P

AN

o lo

nger

pre

sent

, pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Unn

amed

Cre

ekD

elaw

are,

PA

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gU

nnam

ed C

reek

Old

Can

al (

unna

med

)G

louc

este

r, N

JN

o lo

nger

pre

sent

, pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Littl

e T

imbe

r C

reek

Old

Can

al (

unna

med

)G

louc

este

r, N

JN

ote

nam

e ch

ange

Unn

amed

Cre

ekD

elaw

are,

PA

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gC

hest

er C

reek

Che

ster

Cre

ekD

elaw

are,

PA

Rep

aupo

Cre

ekR

epau

po C

reek

Glo

uces

ter,

NJ

Rid

ley

Cre

ekR

idle

y C

reek

Del

awar

e, P

AC

rum

Cre

ekC

rum

Cre

ekD

elaw

are,

PA

Dar

by C

reek

Dar

by C

reek

Del

awar

e, P

AN

ehon

sey

Bro

okU

nnam

ed C

reek

Glo

uces

ter,

NJ

Not

e na

me

chan

geC

lonm

ell C

reek

Clo

nmel

l Cre

ekG

louc

este

r, N

JM

antu

a C

reek

Man

tua

Cre

ekG

louc

este

r, N

JU

nnam

ed C

reek

Unn

amed

Cre

ekG

louc

este

r, N

JN

ote

nam

e ch

ange

Unn

amed

Cre

ekG

louc

este

r, N

JA

ppea

rs a

s a

shor

t unn

amed

fing

er, p

ossi

bly

fille

d or

re -

rout

ed u

nder

grou

nd

Cob

bs C

reek

Del

awar

e/P

hila

delp

hia,

PA

No

long

er p

rese

nt, p

ossi

bly

due

to d

itchi

ng o

r ca

nal

cons

truc

tion

Bow

Cre

ekD

elaw

are/

Phi

lade

lphi

a, P

AN

o lo

nger

pre

sent

, pos

sibl

y du

e to

ditc

hing

or

cana

l co

nstr

uctio

nW

oodb

ury

Cre

ekW

oodb

ury

Cre

ekG

louc

este

r, N

J

Unn

amed

Cre

ekG

louc

este

r, N

JN

o lo

nger

pre

sent

, pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Sch

uylk

ill R

iver

Sch

uylk

ill R

iver

Phi

lade

lphi

a, P

AT

he D

elaw

are

Riv

er's

larg

est t

ribut

ary

Big

Tim

ber

Cre

ekB

ig T

imbe

r C

reek

Glo

uces

ter/

Cam

den,

NJ

Littl

e T

imbe

r C

reek

Littl

e T

imbe

r C

reek

Cam

den,

NJ

Hol

land

er C

reek

Phi

lade

lphi

a, P

AN

o lo

nger

pre

sent

, pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Unn

amed

Cre

ekP

hila

delp

hia,

PA

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gD

RA

FT

Tab

le 4

-13

Pag

e 2

of 3

Page 126: Characterization of Ecological Stressors in the Delaware Estuary

His

tori

cal

Cu

rren

tC

ou

nty

No

tes

TA

BL

E 4

-13

HIS

TO

RIC

AL

AN

D P

RE

SE

NT

–DA

Y T

RIB

UT

AR

IES

OF

TH

E D

EL

AW

AR

E E

ST

UA

RY

LIS

TE

D F

RO

M S

OU

TH

TO

NO

RT

H

New

ton

Cre

ekN

ewto

n C

reek

Cam

den,

NJ

Bra

nche

s cu

t off,

now

form

New

ton

Lake

Unn

amed

Cre

ekP

hila

delp

hia,

PA

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gU

nnam

ed C

reek

Cam

den,

NJ

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gC

oope

r C

reek

Coo

per

Riv

erC

amde

n, N

JU

nnam

ed C

reek

/Can

alA

band

oned

Can

alP

hila

delp

hia,

PA

Can

al a

band

oned

Unn

amed

Cre

ekP

hila

delp

hia,

PA

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gP

ocha

ck C

reek

Cam

den,

NJ

No

long

er p

rese

nt, p

ossi

bly

due

to fi

lling

or

re-r

outin

gP

enns

auke

n C

reek

Pen

nsau

ken

Cre

ekC

amde

n/B

urlin

gton

, NJ

Fra

nkfo

rd C

reek

Fra

nkfo

rd C

reek

Phi

lade

lphi

a, P

A

Wis

sino

min

g C

reek

Phi

lade

lphi

a, P

AA

ppea

rs a

s a

shor

t unn

amed

fing

er, p

ossi

bly

fille

d or

re -

rout

ed u

nder

grou

ndP

ompe

ston

Cre

ekP

ompe

ston

Cre

ekB

urlin

gton

, NJ

Pen

nypa

ck C

reek

Pen

nypa

ck C

reek

Phi

lade

lphi

a, P

AD

amm

ed u

pstr

eam

Sw

ede

Run

Dre

dge

Har

bor

Bur

lingt

on, N

JN

ow fo

rms

Lake

Soo

ey, w

ith n

o ap

pare

nt o

utle

t to

the

Del

awar

eR

anco

cas

Cre

ekR

anco

cas

Cre

ekB

urlin

gton

, NJ

Byb

erry

Cre

ekP

hila

delp

hia,

PA

No

long

er p

rese

nt p

ossi

bly

due

to fi

lling

or

re-r

outin

gP

oque

ssin

g C

reek

Poq

uess

ing

Cre

ekP

hila

delp

hia/

Buc

ks, P

AA

ppea

rs s

hort

ened

, pos

sibl

y re

-rou

ted

unde

rgro

und

Unn

amed

Cre

ekB

urlin

gton

, NJ

No

long

er p

rese

nt p

ossi

bly

due

to fi

lling

or

re-r

outin

gU

nnam

ed C

reek

Buc

ks, P

AN

o lo

nger

pre

sent

pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Nes

ham

iny

Cre

ekN

esha

min

y C

reek

Buc

ks, P

AU

nnam

ed C

reek

Bur

lingt

on, N

JN

o lo

nger

pre

sent

pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Unn

amed

Cre

ekB

urlin

gton

, NJ

No

long

er p

rese

nt p

ossi

bly

due

to fi

lling

or

re-r

outin

gU

nnam

ed C

reek

Buc

ks, P

AN

o lo

nger

pre

sent

pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Ass

iscu

nk C

reek

Ass

iscu

nk C

reek

Bur

lingt

on, N

JM

ill C

reek

Otte

r C

reek

Buc

ks, P

AN

ote

nam

e ch

ange

DE

Div

isio

n P

A C

anal

Buc

ks, P

AA

band

oned

, no

long

er e

mpt

ies

to th

e D

elaw

are

Unn

amed

Cre

ekB

ustle

ton

Cre

ekB

urlin

gton

, NJ

Now

onl

y a

shor

t mar

sh fi

nger

Com

mon

Cre

ekM

artin

s C

reek

Buc

ks, P

AC

hann

eled

, div

erte

d, &

tunn

eled

Sco

tts C

reek

Sco

tts C

reek

Buc

ks, P

AO

rigin

al m

outh

fille

d, n

ow d

amm

ed w

ith o

utle

t upr

iver

Cra

fts C

reek

Cra

fts C

reek

Bur

lingt

on, N

JD

amm

ed n

ear

mou

th, c

reat

ing

smal

l pon

dU

nnam

ed C

reek

Bur

lingt

on, N

JN

ow fo

rms

Cry

stal

Lak

eU

nnam

ed C

reek

Buc

ks, P

AN

o lo

nger

pre

sent

pos

sibl

y du

e to

filli

ng o

r re

-rou

ting

Bla

cks

Cre

ekB

lack

s C

reek

Bur

lingt

on, N

JC

ross

wic

ks C

reek

Cro

ssw

icks

Cre

ekB

urlin

gton

/Mer

cer,

NJ

Duc

k C

reek

Mer

cer,

NJ

His

toric

ally

con

nect

ed to

riv

er o

n no

rth

and

sout

h en

ds,

nort

h en

d no

w fi

lled

Bile

s C

reek

Buc

ks, P

AH

isto

rical

ly c

onne

cted

to r

iver

on

nort

h an

d so

uth

ends

, no

rth

end

now

fille

dA

ssun

pink

Cre

ekA

ssun

pink

Cre

ekM

erce

r, N

JT

unne

led

unde

rgro

und

in T

rent

on

Sou

rce:

Not

e:

The

info

rmat

ion

for

curr

ent t

ribut

arie

s w

as o

btai

ned

from

NO

AA

nav

igat

iona

l sou

ndin

gs m

aps

from

200

2–2

005.

Inf

orm

atio

n fo

r hi

stor

ical

trib

utar

ies

was

ob

tain

ed fr

om h

isto

rical

US

GS

map

s pr

oduc

ed fr

om s

urve

ys th

at w

ere

cond

ucte

d fr

om 1

886

–192

7. (

http

://hi

stor

ical

.map

tech

.com

/)

Sha

ding

indi

cate

s tr

ibut

arie

s th

at n

o lo

nger

exi

st o

n pr

esen

t day

NO

AA

map

s.

DR

AF

TT

able

4-1

3P

age

3 of

3

Page 127: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-14 OVERVIEW OF CAUSES AND SOURCES OF IMPAIRMENTS IN DELAWARE ESTUARY

DRBC River Zone

Use Not Supported Causes Possible Sources

2 Drinking water PCBsBrownfield sites, contaminated sediments, wet weather discharges, unknown sources

2 Fish consumption PCBs, dioxins, mercuryBrownfield sites, contaminated sediments, wet weather discharges, unknown sources, air deposition

3 Drinking water PCBsBrownfield sites, contaminated sediments, wet weather discharges, unknown sources

3 Fish consumption PCBs, dioxins, mercuryBrownfield sites, contaminated sediments, wet weather discharges, unknown sources, air deposition

3 Drinking water PCBsBrownfield sites, contaminated sediments, wet weather discharges, unknown sources

3 Aquatic life Temperature Drought-related impacts, urbanized high density areas

3 Aquatic life Dissolved oxygen

Municipal point source discharges, wet weather discharges, non-point sources, small flow discharges, residential districts

4 Fish consumption PCBs, dioxins, mercury Brownfield sites, contaminated sediments, wet weather discharges, unknown sources, air deposition

4 Aquatic life Temperature Drought-related impacts, urbanized high density areas

4 Aquatic life Copper Unknown sources

5a Fish consumption PCBs, dioxin, mercury, arsenic, chlorinated pesticides

Brownfield sites, contaminated sediments, wet weather discharges, unknown sources, air deposition

5b Aquatic life Copper Unknown sources

5b Fish consumption PCBs, dioxin, mercury, arsenic, chlorinated pesticides

Brownfield sites, contaminated sediments, wet weather discharges, unknown sources, air deposition

5c Aquatic life Dissolved oxygen

Municipal point source discharges, wet weather discharges, non-point sources, small flow discharges, residential districts

5c Fish consumption PCBs, dioxins, mercury Brownfield sites, contaminated sediments, wet weather discharges, unknown sources, air deposition

Source:

DRBC (2004)

DRAFT Page 1 of 1Table 4-14

Page 128: Characterization of Ecological Stressors in the Delaware Estuary

TA

BL

E 4

-15

PC

B M

AS

S L

OA

DIN

G B

Y D

RB

C Z

ON

E (

GR

AM

S P

ER

DA

Y)

DR

Y W

EA

TH

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Page 129: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-16 TOXIC SUBSTANCE LOADINGS TO THE DELAWARE ESTUARY, INCLUDING PCBs

SourcePS (1/2) UR (1/2) AR (1/2) AD (1/2)

Percent of Total Loading by Substance

Arsenic 43.8/7.3 8.9/3.2 46.6/92.2 0.7/2.0 10.4

Chromium 87.4/20.1 11.6/5.8 1.0/3.8 14.3

Copper 82.1/18.7 15.6/7.7 2.3/9.0 14.2

Lead 70.3/13.2 24.5/10.0 5.2/16.9 11.7

Mercury 10.1/0.2 10.1/0.3 79.8/20.2 0.9

Silver 100.0/2.2 1.4

Zinc 52.6/33.4 43.5/59.8 4.0/43.6 39.6

PAH 95.1/10.6 4.9/4.4 3.2

Chlorinated Pesticides 39.5/0.4 2.6/0.1 57.9/7.8 0.7

PCBs 66.7/<0.01 33.3/0.1 <0.01

VOCs 79.0/4.5 21.0/2.6 3.5

Percent of Total Loading by Source

62.3 28.8 5.2 3.6 99.9/99.9

Source:Frithsen et al. (1995) Sutton et al. (1996)

Notes:

1 = percent loading of a substance by source 2 = percent contribution of a substance to loading from a source PS = point source UR = urban runoff AR = agricultural runoff AD = atmosphere deposition

DRAFT Page 1 of 1Table 4-16

Page 130: Characterization of Ecological Stressors in the Delaware Estuary

DRAFTTable 4 17

TABLE 4-17 MEAN CHLORINATED PESTICIDES (µG/KG), PCBS (µG/KG) AND DIOXINS-FURANS (NG/KG) IN SEDIMENT FOR EACH SAMPLING

STATION OF 1997 NOAA NATIONAL STATUS AND TRENDS PROGRAM. PLANAR PCBS IN NG/KG.

Stratum StationMeasured

PCBs

Total PlanarPCBs

Dioxins Furans TotalDDx

Total Chlordanes

Total HCH

Hexa-chloro-

benzene19 1 109.59 319.6 78.49 12.03 0.00 1.66 19 2 7.67 5.43 2.70 0.13 0.31 19 3 105.18 445.7 127.21 18.27 0.75 0.00 20 4 124.63 41.2 222.94 17.57 0.00 2.73 20 5 3.97 4.14 0.69 0.11 0.11 20 6 17.64 27.83 3.99 0.07 0.21 1 7 98.30 589.2 208.23 11.17 0.00 2.09 1 8 103.10 117.75 14.10 0.00 10.30 1 9 17.59 29.90 1.89 0.01 0.12 2 10 35.22 5.2 132.37 2.90 84.04 3.41 0.00 0.33 2 11 50.36 355.5 1,172.76 77.06 32.08 3.30 0.00 0.00 2 12 4.11 13.4 2.71 0.38 0.24 0.13 3 13 294.86 263.7 301.94 3.97 0.00 0.00 3 14 8.16 37.8 7.91 1.23 0.00 0.12 3 15 11.32 21.4 2.75 0.68 0.18 0.10 4 16 233.13 151.89 5.16 0.00 0.42 4 17 33.38 24.72 3.02 0.00 1.44 4 18 18.11 213.5 11.12 2.01 0.41 0.54 5 19 77.72 121.72 14.80 0.36 2.87 5 20 219.94 4112.1 5,157.22 1,017.50 47.63 6.33 2.35 0.76 5 21 48.75 347.7 44.22 6.10 0.14 1.02 6 22 18.17 111.3 9.11 2.33 0.38 0.36 6 23 53.51 24.36 6.14 0.71 1.05 6 24 8.09 2.47 0.36 0.08 0.10 7 25 34.40 14.88 3.50 0.39 0.68 7 26 27.61 14.48 3.01 0.13 0.31 7 27 1.45 30.0# 0.21 0.28 0.07 0.04 8 28 16.29 7.06 2.04 0.07 0.21 8 29 10.74 20.0# 4,682.98 5,663.84 0.40 4.70 0.00 0.00 8 30 28.28 244.1 14.48 3.43 0.53 0.25 9 31 0.75 0.41 0.44 0.00 0.01 9 32 4.42 3.6 0.73 1.16 0.47 0.00 9 33 0.99 0.31 0.15 0.13 0.07 9 34 11.50 6.51 2.40 0.10 0.19

10 35 2.34 0.71 0.09 0.08 0.12 10 36 16.00 10.87 2.32 0.14 0.13 10 37 13.70 181.9 7.33 1.84 0.10 0.08 10 38 7.41 4.49 0.76 0.12 0.07 11 39 2.10 18.0 0.93 0.25 0.04 0.05 11 40 4.66 1.64 0.40 0.05 0.08 11 41 2.13 0.69 0.17 0.03 0.08 11 42 2.17 0.89 0.11 0.03 0.08 12 43 1.53 17.0 0.48 0.12 0.01 0.08 12 44 1.91 0.71 0.17 0.06 0.07 12 45 0.99 0.21 0.06 0.02 0.00 12 46 1.21 0.19 0.01 0.04 0.01 13 47 1.05 0.15 0.07 0.03 0.01 13 48 2.77 0.18 0.11 0.00 0.03 13 49 0.67 0.12 0.12 0.05 0.07 13 50 1.31 0.28 0.10 0.00 0.00 13 51 0.15 0.02 0.00 0.00 0.03 13 52 0.58 0.10 0.04 0.04 0.04 13 53 0.59 0.19 0.03 0.00 0.00 13 54 0.94 17.5 0.23 0.06 0.03 0.00 13 55 1.05 0.24 0.04 0.00 0.00 13 56 3.06 0.89 0.03 0.04 0.02 14 57 9.52 5.55 0.41 0.10 0.26 14 58 1.56 0.47 0.09 0.03 0.04

Page 131: Characterization of Ecological Stressors in the Delaware Estuary

DRAFTTable 4 17

TABLE 4-17 MEAN CHLORINATED PESTICIDES (µG/KG), PCBS (µG/KG) AND DIOXINS-FURANS (NG/KG) IN SEDIMENT FOR EACH SAMPLING

STATION OF 1997 NOAA NATIONAL STATUS AND TRENDS PROGRAM. PLANAR PCBS IN NG/KG.

Stratum StationMeasured

PCBs

Total PlanarPCBs

Dioxins Furans TotalDDx

Total Chlordanes

Total HCH

Hexa-chloro-

benzene14 59 0.76 0.08 0.04 0.00 0.05 14 60 6.05 53.2 0.96 0.27 0.05 0.07 14 61 0.54 0.10 0.04 0.04 0.03 15 62 0.10 0.03 0.01 0.00 0.00 15 63 0.14 0.02 0.03 0.00 0.00 15 64 0.06 1.6 0.00 0.00 0.00 0.00 16 65 0.25 3.3 0.01 0.01 0.00 0.00 16 66 1.14 0.22 0.04 0.00 0.00 16 67 1.23 0.48 0.20 0.08 0.00 17 68 0.36 0.05 0.00 0.00 0.00 17 69 0.23 0.04 0.00 0.00 0.00 17 70 0.08 3.4 0.01 0.00 0.00 0.00 18 71 0.10 3.0 0.04 0.00 0.00 0.01 18 72 0.09 0.02 0.02 0.00 0.00 18 73 0.23 12.0 0.06 0.00 0.00 0.01 21 84 18.67 200# 10.38 2.13 0.23 0.17 21 85 16.58 9.16 1.51 0.32 0.14 21 87 2.03 40# 1.39 0.69 0.00 0.00 22 88 11.60 9.32 2.12 0.23 0.10 22 89 415.70 526.7 13,923.31 242.06 169.95 74.61 1.15 0.80 22 90 50.39 120# 30.92 6.62 0.00 0.12 22 91 32.64 487.4 18.86 2.75 0.29 0.25 22 92 6.99 254.3 14.01 0.62 0.21 0.00

Source:Hartwell et al. (2001)

Notes:# = some isomers were below method detection limit µg/kg = micrograms per kilogram ng/kg = nanograms per kilogram Upper Zone: Strata 1-4 and 19-20 (Stations 1-15) Transition Zone: Strata 5-12 and 21 (Stations 16-31) Lower Zone: Strata 13, 14 and 22 (Stations 32-61) Strata 15-18 (Stations 62-73) are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text

Page 132: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-18 SAMPLE SEGMENTS FOR SEDIMENT CONTAMINANT CONCENTRATION ANALYSIS

Segment Upstream Terminus Downstream Terminus Number of SamplingStations

Area(km2)

1 Just south of upstream end of Trenton Channel and north of Moon Channel (RM = 132; Rkm = 212)

At seaward end of Beverly Channel and upstream end of Enterprise Range (RM = 114.5; Rkm = 184)

4 14.15

2 At seaward end of Beverly Channel and upstream end of Enterprise Range (RM = 114.5; Rkm = 184)

At confluence of Newton Creek with the Delaware River (RM = 97; Rkm = 156)

4 25.51

3 At confluence of Newton Creek with the Delaware River (RM = 97; Rkm = 156)

At confluence of Chester Creek and Old Canal with the Delaware River (RM = 83; Rkm = 133)

5 31.63

4 At confluence of Chester Creek and Old Canal with the Delaware River (RM = 83; Rkm = 133)

Between Gambles Gut to the north and Red Lion Creek to the South (RM = 63; Rkm = 101)

7 67.90

5 Between Gambles Gut to the north and Red Lion Creek to the South (RM = 63; Rkm = 101)

Boundary between Blackbird Creek, DE, and Hope Creek, NJ (RM = 49; Rkm = 79)

3 95.44

6 Boundary between Blackbird Creek, DE, and Hope Creek, NJ (RM = 49; Rkm = 79)

Boundary between Leipsic River, DE (RM = 34; Rkm = 55) and Fortescue Creek, NJ (RM = 28; Rkm = 45)

12 261.85

7 Boundary between Leipsic River, DE (RM = 34; Rkm = 55) and Fortescue Creek, NJ (RM = 28; Rkm = 45)

Mouth of the Delaware Estuary (RM = 0; Rkm = 0)

35 1484.14

Source:Frithsen et al. (1995)

Notes:RM = river mile Rkm = river kilometer km2 = square kilometers Segment 1 approximately corresponds to DRBC Zone 2 Segment 2 approximately corresponds to DRBC Zone 3 Segment 3 approximately corresponds to DRBC Zone 4 Segments 4 and 5 approximately correspond to DRBC Zone 5 Segments 6 and 7 approximately correspond to DRBC Zone 6

DRAFT Page 1 of 1Table 4-18

Page 133: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-19 AVERAGE CONTAMINANT CONCENTRATIONS OF CHLORINATED PESTICIDES IN

SEDIMENT (µG/KG ORGANIC, DRY WEIGHT)

DDT DDD DDE DieldrinSegment 1 13.2 10.3 18.9 1.0Segment 2 0 35.4 37.3 3.3Segment 3 0.1 0 0 1.0Segment 4 0.2 1.5 1.8 0.4Segment 5 0.3 0.1 0.3 0.1Segment 6 0.4 2.2 2.4 0.3Segment 7 0.4 0.7 1.5 0.2

Source:Frithsen et al. (1995)

Notes:µg/kg = micrograms per kilogram

µg/kg micrograms per kilogramSegment 1 approximately corresponds to DRBC Zone 2 Segment 2 approximately corresponds to DRBC Zone 3 Segment 3 approximately corresponds to DRBC Zone 4 Segments 4 and 5 approximately correspond to DRBC Zone 5 Segments 6 and 7 approximately correspond to DRBC Zone 6

DRAFT Page 1 of 1Table 4-19

Page 134: Characterization of Ecological Stressors in the Delaware Estuary

DRAFT Page 1 of 1Table 4-20

TABLE 4-20 COMPARISON OF CHLORDANE ANALYSES IN FISH CONDUCTED AS PART OF THE NEW

JERSEY BIOMONITORING PROGRAM (µG/KG WET WEIGHT)

1986–1987 1988–1991 1998–1999 1986–1987

1998–1999

Common Name RegionMean # Mean # Mean #

Prop>300

Prop>300

Brown bullhead Camden 124 8 102 8 15 38 0.13 0 Brown bullhead Northeast 73 2 53 1 15 6 0 0 American eel Camden 630 7 15 1 0.57 0 American eel Camden 630 7 15 1 0.57 0 American eel Camden 630 7 15 1 0.57 0 Common carp Camden 260 13 275 1 111 60 0.31 0.017 Common carp Northeast 334 4 149 1 55 20 0 0 Largemouth bass Camden 21 5 48 2 19 30 0 0 Largemouth bass Northeast 13 1 6 6 0 0 White perch Northeast 64 6 44 8 0 0 Striped bass North Coast 61 10 8 9 0 0 Striped bass Northeast 50 16 14 5 0 0 Striped bass South Coast 64 5 9 5 0 0 Bluefish North Coast 37 24 7 9 0 0 Bluefish Northeast 30 11 8 10 0 0 Bluefish South Coast 33 29 10 8 0 0

Source:Ashley and Horwitz (2000)

Notes:See Ashley and Horwitz (2000) for geographical distribution of sampling locations Prop>300 = proportion of fish samples exceeding U.S. Food and Drug Administration action limit of 300 µg/kg for chlordane in fish # = number of samples µg/kg = micrograms per kilogram

Page 135: Characterization of Ecological Stressors in the Delaware Estuary

DRAFTTable 4 21

TABLE 4-21 COMPARISON OF DDX EVALUATIONS AS PART OF THE NEW JERSEY BIOMONITORING

PROGRAM (µG/KG WET WEIGHT)

1986–1987 1998–1999 Scientific Region Region

Mean # Mean #Brown bullhead Camden Camden 177 8 33 19Brown bullhead Northeast Raritan-Passaic 193 2 19 3American eel Camden Camden 1300 7 373 1American eel Delaware Delaware River and tribs 412 9 554 25American eel Northeast Raritan-Passaic 261 10 361 8Common carp Camden Camden 540 13 666 30Common carp Northeast Raritan-Passaic 425 4 179 10Largemouth bass Camden Camden 74 5 163 15Largemouth bass Northeast Raritan-Passaic 30 1 17 6White perch Northeast Raritan-Passaic 193 6 263 8Striped bass North Coast Atlantic Ocean north 194 10 100 9Striped bass Northeast Raritan-Passaic 189 16 72 5Striped bass South Coast Atlantic Ocean south 193 5 135 6Bluefish North Coast Atlantic Ocean north 104 24 91 9Bluefish Northeast Raritan-Passaic 102 11 76 10Bluefish South Coast Atlantic Ocean south 96 29 118 8

Source:Ashley and Horwitz (2000)

Notes:See Ashley and Horwitz (2000) for geographical distribution of sampling locations # = number of samples µg/kg = micrograms per kilogram

Page 136: Characterization of Ecological Stressors in the Delaware Estuary

Number of Dischargers Maximum Total Loading

Detected (kg/day)

Zinc 83 465Chromium 39 436Copper 58 246Nickel 46 230Lead 53 72Cadmium 25 27Arsenic 16 14Silver 22 12Selenium 8 1.7Mercury 24 0.6Beryllium 3 0.02

Source:DRBC (1994)

Notes:

kg/day = kilograms per dayRM = river mile

Parameter

TABLE 4-22LOADING ESTIMATE FOR THE MAJOR POINT SOURCE DISCHARGERS

TO THE DELAWARE RIVER (RM 60–130)

DRAFTTable 4-22 Page 1 of 1

Page 137: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-23METALS LOADING TO THE DELAWARE ESTUARY

MetalPoint Source

(%)

Non-Point Sources

TotalAtmosphericDeposition

(%)

UrbanRunoff

(%)

AgriculturalRunoff

(%)

Arsenic 43.8 0.7 8.9 46.6 ~112 x 103 a

Chromium 87.4 1 11.6 NE ~154 x 103 a

Copper 82.1 2.3 15.6 NE ~153 x 103 a

Lead 70.3 5.2 24.5 NE ~126 x 103 a

Mercury 10.1 79.8 10.1 NE ~9.9 x 103 a

Silver 100 NE NE NE ~15 x 103 a

Zinc 52.6 4 43.5 NE ~429 x 103 a

Percent of Total Loading by Source

63.75 13.29 16.3 6.66 100 b

Source:

Frithsen et al. (1995)Sutton et al. (1996)

Notes:NE = no estimate could be madea kg/yr = kilograms per yearb %

DRAFTTable 4-23 Page 1 of 1

Page 138: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-24ESTIMATES FOR METALS LOADINGS FROM ATMOSPHERIC DEPOSITION

ContaminantDeposition Rate

(µg/m2/yr)Direct to Estuary

(kg/yr)From Watershed

(kg/yr)Total

(kg/yr)

Arsenic 150 298 493 791Cadmium 69 137 227 364Chromium 290 577 953 1,529

Copper 660 1,313 2,168 3,481Mercury 1,500 2,983 4,927 7,910Nickel 800 1,591 2,628 4,219Lead 1,250 2,486 4,106 6,592Zinc 3,300 6,564 10,839 17,403

Source:Frithsen et al. (1995)

Notes:

µg/m2/yr = micrograms per square meter per year

kg/yr = kilograms per yearEstimates provided for direct deposition to estuary, indirect input resulting from deposition onthe watershed, and total input from atmospheric deposition.

DRAFTTable 4-24 Page 1 of 1

Page 139: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-25MERCURY VOLATILIZATION FLUXES FROM THE DELAWARE ESTUARY

ZONEWIND SPEED DGM TGM FLUX

(m/s) (pM) (pmol/m3) (pmol/m2/h)

2 8 0.45 6.8 463 6.3 0.6 6.4 444 7.1 0.45 8 395 6.1 0.3 7.1 216 4.6 0.35 8.1 16

Source:Reinfelder and Totten (2006)

Notes:DGM = dissolved gaseous mercury in waterTGM = total gaseous mercury in airm/s = meters per secondpM = picomolar

pmol/m3 = picomoles per cubic meter

pmol/m2/h = picomoles per square meter per hour

DRAFTTable 4-25 Page 1 of 1

Page 140: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-26SEDIMENT EFFECTS LEVEL EXCEEDANCES – DRBC 1991 STUDY

Parameter ER-L (ppm) ER-M (ppm)Highest Concentration

Observed (ppm)Copper 70 390 245Lead 35 110 397Zinc 120 270 952

Cadmium 5.0 9.0 938

Source:DRBC (1994)

Notes:ER-L = Effects range-low; lower 10% of effects data, concentration below which effects are unlikely.ER-M = Effects range-median; median value of effects data, concentration above which toxic effects are probable.ppm = parts per million

DRAFTTable 4-26 Page 1 of 1

Page 141: Characterization of Ecological Stressors in the Delaware Estuary

Estuary Segment Arsenic Cadmium Chromium Copper Lead Mercury Silver Zinc

Segment 1 3.9 2.75 45.1 42.9 47.87 0.09 0.2 435.7Segment 2 0 0.43 36.3 42.5 24.47 0.16 0 367Segment 3 1.78 0.07 42.7 25 28.64 0.18 0.01 193.9Segment 4 2.15 0.15 48.1 23.1 25.35 0.2 0.01 174.1Segment 5 0.3 68.5 20.5 33.21 0.21 0 170.7Segment 6 4.84 0.18 44.5 9.87 16.38 0.07 0.07 97.2Segment 7 6.34 0.34 33.6 6.4 16.72 0.06 0.06 64.5

Source:Frithsen et al. (1995)

Notes:

µg/g = micrograms per gramSegment 1 approximately corresponds to DRBC Zone 2Segment 2 approximately corresponds to DRBC Zone 3Segment 3 approximately corresponds to DRBC Zone 4Segments 4 and 5 approximately correspond to DRBC Zone 5Segments 6 and 7 approximately correspond to DRBC Zone 6

TABLE 4-27AVERAGE CONTAMINANT CONCENTRATIONS IN SEDIMENTS OF THE DELAWARE ESTUARY

METALS (µG/G DRY WEIGHT SEDIMENT)

DRAFTTable 4-27 Page 1 of 1

Page 142: Characterization of Ecological Stressors in the Delaware Estuary

Cadmium Cobalt Copper Iron Manganese Nickel Lead Zinc

Delaware 0.17 0.42 2.36 32.9 155 3.86 0.27 12.1Susquehanna 0.089 1 1.21 57.3 655 5.75 0.21 2.62

Southeastern U.S. (avg.) 0.078 0.56 30.7 18 0.26 0.64Hudson 0.25 3.24 31.9 10.7 2.41 8.83

Connecticut 0.1 4.17 113 45.9 0.98Potomac 0.55

Source:Church et al. (1993) as presented in Sutton et al. (1996)

Note:

µg/L = micrograms per liter

Trace Metal ( g/L)

TABLE 4-28 REPORTED CONCENTRATIONS OF DISSOLVED TRACE METALS

IN SOME EAST COAST RIVERS

River

DRAFTTable 4-28 Page 1 of 1

Page 143: Characterization of Ecological Stressors in the Delaware Estuary

1990 (Estimated) 2020 (Projected)

Total Nitrogen 11.967 x 106 10.438 x 106

Total Phosphorus 5.488 x 105 3.653 x 105

Source:Evans et al. (1993) as presented in Sutton et al. (1996)

Note:

kg/yr = kilograms per year

Load (kg/yr)

DELAWARE ESTUARY NON-POINT SOURCE NUTRIENT LOADSTABLE 4-29

Nutrient

DRAFTTable 4-29 Page 1 of 1

Page 144: Characterization of Ecological Stressors in the Delaware Estuary

Objective Zone 2 Zone 3 Zone 4 Zone 5Minimum 24 hour average of 3.5 mg/L -- X X --Minimum 24 hour average of 5.0 mg/L X -- -- --Minimum 24 hour average concentration: At RM 78.8: 3.5 mg/L At RM 70.0: 4.5 mg/L At RM 59.5: 6.0 mg/LFrom April 1–June 15 and September 16–December 31,

dissolved oxygen shall not have seasonal average < 6.5 mg/L

Source:DRBC (2004)

Notes:All zones refer to DRBC River Zones.mg/L = milligrams per literRM = river mile

DRBC DISSOLVED OXYGEN OBJECTIVES FOR THE DELAWARE ESTUARYTABLE 4-30

X X X X

-- -- -- X

DRAFTTable 4-30 Page 1 of 1

Page 145: Characterization of Ecological Stressors in the Delaware Estuary

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Page 146: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-32 MEAN WET-WEIGHT CONCENTRATIONS (µG/KG) OF PBDEs IN OSPREY EGGS

COLLECTED IN THE DELAWARE RIVER AND BAY REGION AREA1

South2 Central2 North2 River2

Analyte (n =2) (n = 6) (n = 6) (n = 1)

Mean 46.6 124B 276A —Range 43.0–50.1 90.7–231 223–453 227Congener 47

n 2 6 6 1Mean 7.93 18.0 111 —Range 6.20–9.66 8.61–52.8 45.8–228 140Congener 99

n 2 6 6 1Mean 12.40 34.5 99.3 —Range 10.5–14.3 22.2–85.1 62.3–155 82.0Congener 100

n 2 6 6 1Mean 5.32 10.8 40.1 —Range 2.80–7.83 5.93–28.2 11.1–93.3 61.2Congener 153

n 2 6 6 1Mean 7.87 12.5 36.6 —Range 3.44–12.3 6.92–21.0 12.9–68.5 43Congener 154

n 2 6 6 1Mean 2.08 3.32 2.99 —Range 1.43–2.72 1.73–5.28 1.97–3.96 2.27Hexa-a

n 2 6 5 1Mean — 2.15 2.59 —Range ND ND–2.65 ND–3.21 2.50Hexa-c

n 0 4 4 1Mean 82.2AB 206B 572A —Range 70.9–93.5 141–429 442–820 557Total PBDEs

n 2 6 6 1

Source:Toschik et al. (2005)

Notes:PBDE = polybrominated diphenyl ether

µg/kg = micrograms per kilogram

1. First entry for analyte is mean, second the extremes, third the quantifiable n. These analyses were based on a subset of 15 samples based on geographical distribution. ND = not detected, — = no mean value calculated because contaminant was found in fewer than half of samples. Different capital letters signify means determined to be significantly different by Wilcoxon 2-sample t-test (p < 0.05).

2. The “South” study segment encompassed Rehoboth Bay and Indian River Bay along the Delaware Atlantic coast. The “Central” study segment included central and southern Delaware Bay from the C and D Canal to Cape Henlopen. The “North” study segment included the upper tidal portion of the Delaware River from Trenton to the C and D Canal. The “River” study segment encompassed the Easton-East Stroudsburg, including part of the Delaware Water Gap.

DRAFT Page 1 of 1Table 4-32

Page 147: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-33 WET-WEIGHT CONCENTRATIONS (µG/KG) OF PERFLUORINATED COMPOUNDS IN

OSPREY EGGS COLLECTED IN THE DELAWARE RIVER AND BAY AREA1

South2 Central2 North2 River2

Analyte (n = 2) (n = 6) (n = 6) (n = 1)

Mean — 10.0 27.8 —Range 2.38 3.30–29.1 4.49–50.1 NQPerfluorononanoic acid

n 1 6 6 0Mean 2.66B 7.43B 29.8A —Range 1.63–4.33 5.23–12.6 9.54–69.5 4.74Perfluorodecanoic acid

n 2 6 6 1Mean 7.00B 31.8B 121A —Range 4.91–9.98 13.9–86.8 66.0–221 12.8Perfluoroundecanoic acid

n 2 6 6 1Mean 1.89B 4.69B 31.8A —Range 1.58–2.67 2.69–7.28 10.8–72.7 3.69Perfluorododecanoic acid

n 2 6 6 1Mean 37.8B 96.9AB 293A —Range 33.8–42.3 37.4–370 127–799 122Perfluoroctanesulfonate

n 2 6 6 1Mean — 4.96B 26.8A —Range 1.24 2.20–11.6 8.99–52.4 8.98Perfluorodecanesulfonate

n 1 6 6 1

Source:Toschik et al. (2005)

Notes:µg/kg = milligrams per kilogram

1. First entry for analyte is geometric mean, second the extremes, third the quantifiable n. Theseanalyses were based on a subset of 15 samples based on geographical distribution. NQ = not quantifiable, — = no mean value calculated because contaminant was found in fewer than half of samples. Different capital letters signify means determined to be significantly different by Tukey’s multiple comparison test (p < 0.05).

2. The “South” study segment encompassed Rehoboth Bay and Indian River Bay along the Delaware Atlantic coast. The “Central” study segment included central and southern Delaware Bay from the C and D Canal to Cape Henlopen. The “North” study segment included the upper tidal portion of the Delaware River from Trenton to the C and D Canal. The “River” study segment encompassed the Easton-East Stroudsburg, including part of the Delaware Water Gap.

DRAFT Page 1 of 1Table 4-33

Page 148: Characterization of Ecological Stressors in the Delaware Estuary

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Page 149: Characterization of Ecological Stressors in the Delaware Estuary

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Page 150: Characterization of Ecological Stressors in the Delaware Estuary

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Exo

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fera

Eas

tern

Spi

ny S

ofts

hell

Nat

ive

Tra

nspl

ant

Rep

tiles

-Tur

tles

Em

ydid

aeM

alac

lem

ys te

rrap

inD

iam

ond-

back

ed T

erra

pin

Nat

ive

Tra

nspl

ant

Sou

rce:

US

GS

(20

06a)

Not

e:H

UC

= H

ydro

logi

c U

nit C

ode

desi

gnat

ed b

y U

SG

S

DR

AF

TT

able

4-3

5P

age

2 of

2

Page 152: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-36COMMON INVASIVE PLANT SPECIES FOUND ALONG

THE DELAWARE ESTUARY

SpeciesState

Delaware New Jersey PennsylvaniaPhragmites australis (Common reed) XLythrum salicaria (Purple loosestrife) X XMelilotus officinalis (L.) Pallas (Yellowsweetclover)

X

Microstegium vimineum (Trin.) A. Camus (Japanese stiltgrass)

X

Myriophyllum spicatum (Eurasian water-milfoil)

X X X

Polygonum cuspidatum Sieb. & Zudd. (Japanese knotweed)

X X

Polygonum perfoliatum (Mile-a-minute) X X X

Trapa natans (Water chestnut) X

Source:NJDEP, Natural Heritage Program (2004)PADCNR (2006)USGS (2006b)

DRAFTTable 4-36 Page 1 of 1

Page 153: Characterization of Ecological Stressors in the Delaware Estuary

Map Unit % Cover Map Unit % Cover

Spartina alterniflora 28.64 Spartina alterniflora 62.23Tidal Flat 26.44 Phragmites australis 13.38Open Water (Not Impounded) 14.21 Impoundment-Logan Lane 7.54Phragmites australis 11.05 Open Water (Not Impounded) 7.03Spartina alterniflora Mix 4.74 Marsh Shrub - High Salinity 3.63Tidal Swamp Forest 4.2 Salt hay (Spartina ) 2.37Marsh Shrub - Low Salinity 3.64 Spartina cynosuroides 1.68Spartina cynosuroides 2.72 Tidal Swamp Forest 0.92Typha 1.53 Tidal Flat 0.72Zizania aquatica 1.09 Marsh Shrub - Low Salinity 0.43Peltandra virginica 0.96 Typha (latifolia/angustifolia) 0.04Pontederia cordata 0.44 Scirpus americanus 0.02Impoundment 0.3 Atriplex triangularis 0.01Nuphar lutea 0.04 Peltandra virginica 0.01Scirpus americanus 0.01

Total 100% Total 100%

Source:Delaware DNREC (1999)

Note:DNERR = Delaware National Estuarine Research Reserve% = percent

Upper Blackbird Creek Lower St. Jones River

TABLE 4-37PERCENT COMPOSITION OF COVER TYPES FOUND IN DNERR WETLANDS

DRAFTTable 4-37 Page 1 of 1

Page 154: Characterization of Ecological Stressors in the Delaware Estuary

TABLE 4-38LIST OF KEY SPECIES USED IN ASSESSMENT OF FISHERY RESOURCES

IN THE DELAWARE ESTUARY

Anadromous / Catadromous

Estuary Resident / Estuary Dependent

Estuary Dependent / Marine Migratory

American shad American oyster WeakfishStriped bass Hard clam Bluefish

Alewife Carp Summer flounderBlueback herring Catfish Spot

Sturgeon Horseshoe crab SharksAmerican eel White perch Atlantic croaker

Blue crab Atlantic menhadenBlack drum

Tautog

Source:Killam and Richkus (1992)

DRAFTTable 4-38 Page 1 of 1

Page 155: Characterization of Ecological Stressors in the Delaware Estuary

Hig

hM

ediu

mL

ow

Tot

al w

ater

with

draw

al in

E

stua

ry;

Coo

ling

wat

er in

take

vo

lum

e fo

r po

wer

pla

nts

With

draw

al >

50%

(Z

one

5);

mos

t sig

nific

ant c

oolin

g w

ater

in

take

s >

50

MG

D (

Zon

e 5)

With

draw

al <

50%

, >

30%

(Z

ones

2–3

); o

rw

ater

with

draw

al >

50%

, bu

t ver

y fe

w c

oolin

g w

ater

in

take

s >

50

MG

D (

Zon

e 4)

Wat

er w

ithdr

awal

< 3

0%

(Zon

e 6)

; no

cool

ing

wat

er

inta

ke >

50

MG

D (

Zon

e 6)

US

EP

A (

2002

);

San

toro

(20

04)

Dro

ught

and

sea

leve

l ris

e as

sum

ed to

affe

ct a

ll zo

nes

equa

lly.

Sig

nific

ant

impi

ngem

ent/e

ntra

inm

ent

effe

cts

wer

e no

ted

for

Zon

e 5

with

larg

est w

ater

with

draw

als

com

ing

from

Sal

em N

ucle

ar

Gen

erat

ing

Sta

tion.

Tot

al c

onsu

mpt

ive

use

Wat

er u

se >

50%

(no

Zon

es)

Wat

er u

se <

50%

,>

30%

(Z

ones

2–5

)W

ater

use

< 3

0%

(Zon

e 6)

San

toro

(20

04)

Dro

ught

and

sea

leve

l ris

e as

sum

ed to

affe

ct a

ll zo

nes

equa

lly

Wat

er T

emp

erat

ure

DR

BC

wat

er q

ualit

y cr

iteria

; am

ount

of u

rban

ar

ea

DR

BC

tem

pera

ture

crit

eria

ex

ceed

ed (

Zon

es 3

–4)

DR

BC

tem

pera

ture

crit

eria

no

t exc

eede

d. Z

one

is

pres

ent i

n ur

ban

area

(Z

one

2)

DR

BC

tem

pera

ture

crit

eria

no

t exc

eede

d (Z

ones

5–6

);

redu

ced

urba

n ar

eas

rela

tive

to u

pstr

eam

zon

es

DR

BC

(20

04)

DR

BC

(20

04)

stat

es th

at

tem

pera

ture

crit

eria

ex

ceed

ance

s ar

e du

e to

a

com

bina

tion

of d

roug

ht a

nd

amou

nt o

f urb

aniz

ed a

rea.

One

sm

all a

rea

of Z

one

6 (U

nit 6

brB

) ha

s be

en n

oted

as

impa

ired

by D

RB

C, b

ut th

is

was

loca

lized

and

not

re

flect

ive

of th

e zo

ne a

s a

who

le

Sal

init

yS

alin

ity in

trus

ion

Are

a w

here

sal

t lin

e en

croa

chm

ent i

s oc

curr

ing

(Zon

e 4)

NR

NR

San

toro

(20

04);

DE

LEP

(19

96);

S

mul

len

et a

l. (1

984)

Zon

es 2

and

3 a

re u

pstr

eam

of

the

poin

t whe

re s

alin

ity

intr

usio

n is

occ

urrin

g. Z

ones

5

and

6 ar

e na

tura

lly m

ore

salin

e an

d no

t sub

ject

to

salin

ity in

trus

ion.

Pos

sibl

e fu

ture

sal

inity

intr

usio

n du

e to

se

a le

vel r

ise

is n

ot c

onsi

dere

da

curr

ent s

tres

sor

Loca

tion

of D

elaw

are

Est

uarin

e T

urbi

dity

M

axim

um (

ET

M);

S

edim

ent i

nput

from

tr

ibut

arie

s an

d re

susp

ensi

on

ET

M p

rese

nt in

Zon

es 4

-5;

sign

ifica

nt d

owns

trea

m tr

ansp

ort

of r

esus

pend

ed b

otto

m s

edim

ent

NA

Low

est s

edim

ent i

nput

(Z

one

6);

zone

s ar

e ou

tsid

e E

TM

(Z

ones

2-3

, 6)

Som

mer

field

and

M

adse

n (2

003)

; S

anto

ro (

2004

); W

alsh

(2

004)

Trib

utar

ies

and

botto

m

resu

spen

sion

dee

med

mos

t im

port

ant i

nput

s of

sus

pend

ed

solid

s, w

ith h

ighe

st in

put f

rom

do

wns

trea

m tr

ansp

ort o

f bo

ttom

sed

imen

t

Ses

ton

conc

entr

atio

nR

elat

ivel

y hi

gher

obs

erve

d co

ncen

trat

ions

(Zon

es 4

-5)

NA

Low

er o

bser

ved

conc

entr

atio

ns(Z

ones

2-3

, 6)

Big

gs e

t al.

(198

3);

Sha

rp (

pers

. com

m.)

--

Sed

imen

tati

on

Sed

imen

t gra

in s

ize

Fin

e se

dim

ent g

rain

siz

e m

ore

prev

alen

t (Z

ones

5–6

)T

rans

ition

from

fine

to

coar

ser

sedi

men

t (Z

one

4)

Coa

rse

sedi

men

t gra

in s

ize

mor

e pr

eval

ent

(Zon

es 2

–3)

Som

mer

field

and

M

adse

n (2

003)

;S

anto

ro (

2004

);W

alsh

(20

04)

Fin

e-gr

aine

d se

dim

ent

indi

cate

s in

crea

sed

sedi

men

tatio

n/de

posi

tion.

Coa

rse-

grai

ned

sedi

men

t in

dica

tes

high

er e

nerg

y/ n

on-

depo

sitio

nal e

nviro

nmen

t

Hab

itat

Lo

ssD

egre

e of

rip

aria

n de

velo

pmen

tIn

tens

e in

dust

rial/

urba

n de

velo

pmen

t (Z

ones

2–4

)

Hig

h de

velo

pmen

t in

port

ions

of z

one;

mod

erat

e ov

eral

l de

velo

pmen

t(Z

one

5)

Leas

t am

ount

of o

vera

ll de

velo

pmen

t (Z

one

6)B

erge

r et

al.

(199

4);

Sul

livan

et a

l. (1

991)

--

Ph

ysic

al

Wat

er V

olu

me

RA

TIO

NA

LE

FO

R A

SS

IGN

ME

NT

OF

RE

LA

TIV

E R

AN

KIN

G O

F S

TR

ES

SO

R M

AG

NIT

UD

E IN

TH

E D

EL

AW

AR

E E

ST

UA

RY

TA

BL

E 5

-1

So

urc

eC

rite

ria

for

Rel

ativ

e S

tres

sor

Mag

nit

ud

e R

anki

ng

Str

esso

r C

ateg

ory

Su

spen

ded

So

lids

Str

esso

rM

etri

cO

ther

Co

mm

ents

DR

AF

TT

able

5-1

Pag

e 1

of 3

Page 156: Characterization of Ecological Stressors in the Delaware Estuary

Hig

hM

ediu

mL

ow

RA

TIO

NA

LE

FO

R A

SS

IGN

ME

NT

OF

RE

LA

TIV

E R

AN

KIN

G O

F S

TR

ES

SO

R M

AG

NIT

UD

E IN

TH

E D

EL

AW

AR

E E

ST

UA

RY

TA

BL

E 5

-1

So

urc

eC

rite

ria

for

Rel

ativ

e S

tres

sor

Mag

nit

ud

e R

anki

ng

Str

esso

r C

ateg

ory

Str

esso

rM

etri

cO

ther

Co

mm

ents

Hig

hest

tota

l PA

H

conc

entr

atio

ns in

upp

er

Est

uary

—P

hila

delp

hia

and

area

s no

rth

(Z

ones

2–3

)

NA

NA

Cos

ta a

nd S

auer

(1

994)

--

Sta

tions

1–1

4 ha

d re

lativ

ely

high

est P

AH

con

cent

ratio

ns(Z

ones

2–3

)

Indi

vidu

al p

eaks

of h

igh

PA

Hs,

but

mul

tiple

low

er

conc

entr

atio

n sa

mpl

es

(Zon

es 4

–5)

Low

est c

once

ntra

tions

ap

proa

chin

g B

ay(Z

one

6)H

artw

ell e

t al.

(200

1)--

Load

ings

Gre

ates

t loa

ding

s (Z

one

3)Le

sser

load

ings

(Zon

es 4

–5)

Low

est l

oadi

ngs

(Zon

es 2

, 6)

DR

BC

(20

03b;

199

8)Lo

adin

gs b

ased

on

mod

eled

es

timat

es o

f pen

ta-P

CB

va

lues

Sed

imen

t - c

once

ntra

tion

Hig

hest

obs

erve

d co

ncen

trat

ions

co

nsis

tent

ly(Z

ones

2–4

)

Indi

vidu

al p

eaks

of h

igh

PC

Bs,

but

mul

tiple

low

er

conc

entr

atio

n sa

mpl

es

(Zon

e 5)

Low

est c

once

ntra

tions

ap

proa

chin

g B

ay(Z

one

6)H

artw

ell e

t al.

(200

1)--

Tis

sue

- co

ncen

trat

ion

Hig

hest

obs

erve

d co

ncen

trat

ions

(

Zon

es 3

–4)

Indi

vidu

al p

eaks

of h

igh

PC

Bs,

but

mul

tiple

low

er

conc

entr

atio

n sa

mpl

es

(Zon

e 5)

Low

est c

once

ntra

tions

ap

proa

chin

g B

ay(Z

one

6)A

shle

y et

al.

(200

4)--

Hig

hest

con

cent

ratio

ns in

upp

er

Est

uary

—P

hila

delp

hia

and

area

s no

rth

(Zon

es 2

–3)

NA

NA

Cos

ta a

nd S

auer

(1

994)

--

Con

sist

ently

hig

hest

co

ncen

trat

ions

in T

rent

on a

nd

Phi

lade

lphi

a re

gion

s(Z

ones

2–3

)

Low

er c

once

ntra

tions

in

Zon

e 4

Low

est c

once

ntra

tions

in

Zon

e 5.

Nea

r no

n-de

tect

co

ncen

trat

ions

in Z

one

6.H

artw

ell e

t al.

(200

1)

Dec

reas

ed c

once

ntra

tions

ob

serv

ed in

Zon

e 5

are

nota

bly

high

er th

an n

ear

non-

dete

ct c

once

ntra

tions

in Z

one

6. C

hlor

dane

con

cent

ratio

n pa

ttern

s tr

ack

tota

l DD

T.

Har

twel

l et a

l. (2

001)

incl

udes

ch

lord

ane-

rela

ted

com

poun

ds

and

othe

r cy

clod

iene

pe

stic

ides

with

chl

orda

nes

Ch

emic

al

Pes

tici

des

PC

Bs

Pet

role

um

, PA

Hs

and

R

elat

ed C

om

po

un

ds

Sed

imen

t - c

once

ntra

tion

Sed

imen

t - D

Dx

conc

entr

atio

n

DR

AF

TT

able

5-1

Pag

e 2

of 3

Page 157: Characterization of Ecological Stressors in the Delaware Estuary

Hig

hM

ediu

mL

ow

RA

TIO

NA

LE

FO

R A

SS

IGN

ME

NT

OF

RE

LA

TIV

E R

AN

KIN

G O

F S

TR

ES

SO

R M

AG

NIT

UD

E IN

TH

E D

EL

AW

AR

E E

ST

UA

RY

TA

BL

E 5

-1

So

urc

eC

rite

ria

for

Rel

ativ

e S

tres

sor

Mag

nit

ud

e R

anki

ng

Str

esso

r C

ateg

ory

Str

esso

rM

etri

cO

ther

Co

mm

ents

Hig

hest

mea

n co

ncen

trat

ions

of

mos

t met

als

(Zon

es 2

–3)

NA

NA

Frit

hsen

et a

l. (1

995)

Bas

ed o

n da

taba

se

sum

mar

ies

incl

udin

g U

SE

PA

E

MA

P/ S

TO

RE

T a

nd N

OA

A

Nat

iona

l Sta

tus

and

Tre

nds.

Con

sist

ently

hig

h to

tal m

etal

s pe

aks

(Zon

es 2

–3)

Indi

vidu

al p

eaks

of h

igh

met

als,

but

mul

tiple

low

er

conc

entr

atio

n sa

mpl

es(Z

ones

4–5

)

Low

est c

once

ntra

tions

ap

proa

chin

g B

ay(Z

one

6)H

artw

ell e

t al.

(200

1)--

Tis

sue

- co

ncen

trat

ion

Hig

hest

mer

cury

con

cent

ratio

ns

obse

rved

bet

wee

n P

hila

delp

hia-

Wilm

ingt

on (

Zon

es 3

–5)

NA

NA

Brig

htbi

ll et

al.

(200

4)--

Nu

trie

nts

Load

ings

and

co

ncen

trat

ion

Hig

hest

load

ings

nea

r W

WT

Ps,

pa

rtic

ular

ly T

rent

on-P

hila

delp

hia

(Zon

es 2

–3);

lar

ge n

utrie

nt in

put

from

nor

ther

n D

elaw

are

Riv

er;

high

est o

bser

ved

conc

entr

atio

ns

(Zon

es 2

-4)

Rel

ativ

ely

mod

erat

e in

put

in Z

one

5 co

mpa

red

to

Zon

es 2

–4; m

oder

ate

conc

entr

atio

ns in

Z

one

5

Rel

ativ

ely

low

est l

oadi

ngs

and

conc

entr

atio

ns

appr

oach

ing

Bay

(Z

one

6)

San

toro

(20

04);

G

otth

olm

et a

l. (1

994)

; S

harp

(pe

rs. c

omm

.)

Gre

ates

t nut

rient

load

ings

be

lieve

d to

res

ult f

rom

W

WT

Ps

and

mai

nste

m o

f D

elaw

are

Riv

er n

orth

of t

he

Est

uary

. H

ighe

st n

utrie

nt

conc

entr

atio

ns o

bser

ved

in

Zon

es 2

-4.

Dis

solv

ed O

xyg

enS

patia

l con

cent

ratio

ns;

perc

ent s

atur

atio

n

Low

est o

bser

ved

oxyg

en

satu

ratio

n an

d co

ncen

trat

ions

(Z

ones

3-5

)

Mod

erat

e de

gree

of

oxyg

en s

atur

atio

n;

incr

ease

in c

once

ntra

tions

(Z

one

2)

Hig

hest

deg

rees

of o

xyge

n sa

tura

tion;

hig

hest

co

ncen

trat

ions

(Zon

e 6)

San

toro

(20

04);

Sha

rp (

pers

. com

m.)

--

Pat

ho

gen

sO

yste

r di

seas

eD

isea

se e

xist

s an

d is

su

bsta

ntia

lly d

ecre

asin

g oy

ster

po

pula

tions

(Z

one

6)N

RN

R

Par

tner

ship

for

the

Del

awar

e E

stua

ry

(200

2); S

utto

n et

al.

(199

6)

Whe

re d

isea

se e

xist

s it

has

deci

mat

ed o

yste

r po

pula

tions

an

d is

hav

ing

a si

gnifi

cant

ef

fect

. O

ther

zon

es d

o no

t su

ppor

t sig

nific

ant o

yste

r po

pula

tions

Not

es:

-- =

no

addi

tiona

l com

men

tsN

A =

no

data

ava

ilabl

e fr

om th

is s

tudy

to s

uppo

rt r

anki

ngs

NR

= n

ot r

elev

ant

Sed

imen

t - c

once

ntra

tion

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Page 158: Characterization of Ecological Stressors in the Delaware Estuary

Zo

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Page 159: Characterization of Ecological Stressors in the Delaware Estuary

Figures

Page 160: Characterization of Ecological Stressors in the Delaware Estuary

06/09/06 SYR-D85-DJH42321001/42321n01.cdr

THE DELAWARE RIVER ESTUARY

FIGURE

1-1

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:DRBC (NO DATE)

DRAFT

=Delaware River Basin Boundary

Cape Henlopen

Page 161: Characterization of Ecological Stressors in the Delaware Estuary

DELAWARE RIVER STUDY

06/09/06 SYR-D85-DJH42321001/42321N35.cdr

ECOLOGICAL ZONESAND TIDAL WETLANDS

FIGURE

2-1

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

SOURCE:USFWS (1994) AS PRESENTEDIN SUTTON ET AL. (1996)

DRAFT

54 Miles

80 Miles

153 Miles

0 Miles

Page 162: Characterization of Ecological Stressors in the Delaware Estuary

DELAWARE RIVER STUDY

SOURCE:DRBC (2004)

06/21/06 SYR-D85-DJH42321001/42321n03.cdr

WATER QUALITY MANAGEMENT ZONESOF THE DELAWARE RIVER

FIGURE

2-2

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DRAFT

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FEDERAL DREDGED MATERIAL DISPOSALSITES IN THE DELAWARE ESTUARY

FIGURE

4-6

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:USACE (1997)

DRAFTFIGURE

3-1

Page 164: Characterization of Ecological Stressors in the Delaware Estuary

Trenton

Rancocas Creek

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE3-2a

Outfalls Within 1 mile of the Delware Estuary

DELAWARE RIVER STUDY

LegendFor security reasons, the State of PE does notpublicly publish municipal outfall locations

The State of DE publishesNPDES-permitted outfalls

OUTFALLSWITHIN 1 MILE OF THE DELAWARE ESTUARY

FIGURE

3-2a

A

E.I. DuPONT de NEMOURS AND COMPANY

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

OUTFALLS WITHIN 1 MILE OF THE DELAWARERIVER AND ITS TRIBUTARIES

Page 165: Characterization of Ecological Stressors in the Delaware Estuary

Camden

Philadelphia

Schuylkill R

iver

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE3-2b

Outfalls Within 1 mile of the Delware Estuary

DELAWARE RIVER STUDY

LegendFor security reasons, the State of PE does notpublicly publish municipal outfall locations

The State of DE publishesNPDES-permitted outfalls

OUTFALLSWITHIN 1 MILE OF THE DELAWARE ESTUARY

FIGURE

3-2b

E.I. DuPONT de NEMOURS AND COMPANY

A

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

OUTFALLS WITHIN 1 MILE OF THE DELAWARERIVER AND ITS TRIBUTARIES

Page 166: Characterization of Ecological Stressors in the Delaware Estuary

Salem

Wilmington

C&D Canal

Oldmans Creek

Christina River

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE3-2c

Outfalls Within 1 mile of the Delware Estuary

DELAWARE RIVER STUDY

LegendFor security reasons, the State of PE does notpublicly publish municipal outfall locations

The State of DE publishesNPDES-permitted outfalls

OUTFALLSWITHIN 1 MILE OF THE DELAWARE ESTUARY

FIGURE

3-2c

E.I. DuPONT de NEMOURS AND COMPANY

A

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

OUTFALLS WITHIN 1 MILE OF THE DELAWARERIVER AND ITS TRIBUTARIES

Page 167: Characterization of Ecological Stressors in the Delaware Estuary

Trenton

Rancocas Creek

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE3-3a

Facilities Listed on US EPA’s ToxicRelease Inventory (TRI) Through 2003

DELAWARE RIVER STUDYLegend

FACILITIES LISTED ON USEPA'S TOXIC RELEASE INVENTORY (TRI) THROUGH 2003

FIGURE

3-3a

E.I. DuPONT de NEMOURS AND COMPANY

USEPA's

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

FACILITIES LISTED ON USEPA'S TOXIC RELEASEINVENTORY (TRI) THROUGH 2003 FOR THEDELAWARE RIVER AND ITS TRIBUTARIES

Page 168: Characterization of Ecological Stressors in the Delaware Estuary

Camden

Philadelphia

Schuylkill R

iver

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE3-3b

Facilities Listed on US EPA’s ToxicRelease Inventory (TRI) Through 2003

DELAWARE RIVER STUDYLegend

FACILITIES LISTED ON USEPA'S TOXIC RELEASE INVENTORY (TRI) THROUGH 2003

FIGURE

3-3b

E.I. DuPONT de NEMOURS AND COMPANY

USEPA's

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

FACILITIES LISTED ON USEPA'S TOXIC RELEASEINVENTORY (TRI) THROUGH 2003 FOR THEDELAWARE RIVER AND ITS TRIBUTARIES

Page 169: Characterization of Ecological Stressors in the Delaware Estuary

Salem

Wilmington

C&D Canal

Oldmans Creek

Christina River

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE3-3c

Facilities Listed on US EPA’s ToxicRelease Inventory (TRI) Through 2003

DELAWARE RIVER STUDYLegend

FACILITIES LISTED ON USEPA'S TOXIC RELEASE INVENTORY (TRI) THROUGH 2003

FIGURE

3-3c

E.I. DuPONT de NEMOURS AND COMPANY

USEPA's

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

FACILITIES LISTED ON USEPA'S TOXIC RELEASEINVENTORY (TRI) THROUGH 2003 FOR THEDELAWARE RIVER AND ITS TRIBUTARIES

Page 170: Characterization of Ecological Stressors in the Delaware Estuary

06/21/06 SYR-D85-DJH42321001/SF/TEMPLATE.cdr

FIGURE

4-1

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

AVERAGE ANNUAL STREAMFLOW AT TRENTON, NEW JERSEY, FOR THE PERIOD

1910-1990

SOURCE:SUTTON ET AL. (1996)

DRAFT

SOURCE:NAJARIAN ASSOCIATES, INC (1993) AS PRESENTEDIN SUTTON ET AL. (1996)

Page 171: Characterization of Ecological Stressors in the Delaware Estuary

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42321001/SF/TEMPLATE.cdr

FIGURE

4-2

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

TOTAL WATER USE

WITHDRAWALS, 1996

SOURCE:

SANTORO (2004)

DRAFT

Page 172: Characterization of Ecological Stressors in the Delaware Estuary

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42321001/SF/TEMPLATE.cdr

FIGURE

4-3

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

COMSUMPTIVE WATER

USE, 1996

SOURCE:

SANTORO (2004)

DRAFT

Page 173: Characterization of Ecological Stressors in the Delaware Estuary

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42321001/SF/TEMPLATE.cdr

FIGURE

4-4

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

MEAN TIDAL RANGES FOR THREE

STATIONS, 1920-1990

SOURCE:

NAJARIAN ASSOCIATES, INC. (1993)

DRAFT

Page 174: Characterization of Ecological Stressors in the Delaware Estuary

06/21/06 SYR-D85-DJH

42321001/SF/TEMPLATE.cdr

FIGURE

4-5

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

PROJECTED SEA-LEVEL RISE IN THE

DELAWARE ESTUARY

SOURCE:

SUTTON ET AL. (1996)

DRAFT

SOURCE:KRAFT (1988) AS PRESENTEDIN SUTTON ET AL. (1996)

Page 175: Characterization of Ecological Stressors in the Delaware Estuary

06/21/06 SYR-D85-DJH

42321001/SF/TEMPLATE.cdr

FIGURE

4-6

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

AVERAGE MONTHLY WATER TEMPERATURES IN THE

DELAWARE ESTUARY AT BENJAMIN FRANKLIN BRIDGE AT

PHILADELPHIA, PENNSYLVANIA, APRIL TO NOVEMBER

SOURCE:

KREJMAS ET AL. (2005)

DRAFT

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06/21/06 SYR-D85-DJH

42321001/SF/TEMPLATE.cdr

FIGURE

4-7

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SALINITY DISTRIBUTION IN THE

DELAWARE ESTUARY BASIN

SOURCE:

DRAFT

BRYANT AND PENNOCK (1998)

Parts Per Thousand ( )0 00

BRYANT AND PENNOCK (1988)

Page 177: Characterization of Ecological Stressors in the Delaware Estuary

06/21/06 SYR-D85-DJH

42321001/SF/TEMPLATE.cdr

FIGURE

4-8

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

APPROXIMATE RIVER MILE LOCATION RANGE

OF THE 7-DAY AVERAGE OF THE 250-PPM

ISOCHLOR, 1999 - 2003

SOURCE:

SANTORO (2004)

DRAFT

Page 178: Characterization of Ecological Stressors in the Delaware Estuary

06/21/06 SYR-D85-DJH

42321001/SF/TEMPLATE.cdr

FIGURE

4-9

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

DELAWARE ESTUARY WATER USE

SOURCE:

SUTTON ET AL. (1996)

DRAFT

Note:Figure Originally Presented by Albert andPollison (1989) In: The state of theestuary: Summary report of the October19, 1989 workshop, Delaware EstuaryProgram Scientific Technical AdvisoryCommittee Report.

Note:Data from unspecified time period.

SOURCE:ALBERT AND POLLISON (1989) AS PRESENTEDIN SUTTON ET AL. (1996)

Page 179: Characterization of Ecological Stressors in the Delaware Estuary

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FIGURE

4-10

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SESTON (MG/L) CONCENTRATIONS VS. DISTANCE

ABOVE THE MOUTH OF THE ESTUARY WITH

SHADED AREAS FOR 1980-1983

SOURCE:

SHARP (1983)

DRAFT

SESTON (MG/L) CONCENTRATIONS VS. DISTANCEABOVE THE MOUTH OF THE ESTUARY FOR

1980-1983

Notes:Shaded area envelopes all data from 1980-1983 sampling

Notes:Shaded area envelopes all data from 1980-1983 sampling.

SOURCE:BIGGS et al. (1983)SOURCE:BIGGS ET AL. (1983)

Page 180: Characterization of Ecological Stressors in the Delaware Estuary

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FIGURE

4-55DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HARTWELL ET AL. (2001)

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS

(TETRA-, TRI-, DI,- AND MONO-BT) IN SEDIMENT (DRY

WEIGHT) AT DELWARE BAY SAMPLING STATIONS

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS(TETRA-,TRI-,DI,- AND MONO-BT) IN SEDIMENT AT

DELAWARE ESTUARY SAMPLING STATIONS (DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-11

TOTAL SUSPENDED SEDIMENTS (SESTON)VERSUS DISTANCE DOWN DELAWARE ESTUARY

Notes:Composite data from sampling cruises(1978-2003).

SOURCE:SHARP (PERSONAL COMMUNICATION)

Page 181: Characterization of Ecological Stressors in the Delaware Estuary

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FIGURE

4-55DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HARTWELL ET AL. (2001)

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS

(TETRA-, TRI-, DI,- AND MONO-BT) IN SEDIMENT (DRY

WEIGHT) AT DELWARE BAY SAMPLING STATIONS

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS(TETRA-,TRI-,DI,- AND MONO-BT) IN SEDIMENT AT

DELAWARE ESTUARY SAMPLING STATIONS (DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-12

SOURCE:SHARP (PERSONAL COMMUNICATION)

CHLOROPHYLL-A BIOMASS IN THE DELAWAREESTUARY

Notes:Seasonal averages from sampling cruises(1978-2003).

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FIGURE

4-11

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SPATIAL DISTRIBUTION OF SEDIMENT TYPES

ACROSS THE INDUSTRIAL CORRIDOR OF THE

DELAWARE RIVER

SOURCE:

SANTORO (2004)

DRAFT

FIGURE

4-13

Page 183: Characterization of Ecological Stressors in the Delaware Estuary

06/21/06 SYR-D85-DJH

42321001/SF/TEMPLATE.cdr

FIGURE

4-12

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SPATIAL DISTRIBUTION OF SEDIMENT TYPES IN

THE TIDAL DELAWARE RIVER ALONG THE

INDUSTRIAL CORRIDOR

SOURCE:

SANTORO (2004)

DRAFT

FIGURE

4-14

Page 184: Characterization of Ecological Stressors in the Delaware Estuary

06/21/06 SYR-D85-DJH

42321001/SF/TEMPLATE.cdr

FIGURE

4-13

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

CATEGORIES OF MAJOR DISCHARGES

TO THE DELAWARE ESTUARY, 1988

SOURCE:

BRYANT AND PENNOCK (1988), AS

PRESENTED IN BBL & INTEGRAL (2006)

DRAFT

FIGURE

4-15

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42321001/SF/TEMPLATE.cdr

FIGURE

4-14

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SAMPLE LOCATIONS AND SAMPLING STRATA IN THE

DELAWARE RIVER EVALUATED UNDER NOAA'S 1997

NATIONAL STATUS AND TRENDS PROGRAM

SOURCE:

HARTWELL ET AL. (2001)

DRAFT

Notes:Sampling locations are assigned to DRBC River Zones in text.

FIGURE

4-16

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Trenton

Rancocas Creek

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-15a

LOCATION OF SEDIMENT SAMPLING STATIONSUPPER STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDY

Legend

FIGURE

4-15aDelaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

LOCATION OF SEDIMENT SAMPLING STATIONSBASED ON REGIONAL SURVEYS

LOCATION OF SEDIMENT SAMPLING STATIONS FORTHE DELAWARE RIVER AND ITS TRIBUTARIES

BASED ON REGIONAL SURVEYSFIGURE

4-17a

Page 187: Characterization of Ecological Stressors in the Delaware Estuary

Camden

Philadelphia

Schuylkill River

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-15b

LOCATION OF SEDIMENT SAMPLING STATIONSMIDDLE STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDY

Legend

FIGURE

4-15b

LOCATION OF SEDIMENT SAMPLING STATIONSBASED ON REGIONAL SURVEYS

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

LOCATION OF SEDIMENT SAMPLING STATIONS FORTHE DELAWARE RIVER AND ITS TRIBUTARIES BASED

ON REGIONAL SURVEYSFIGURE

4-17b

Page 188: Characterization of Ecological Stressors in the Delaware Estuary

Salem

Wilmington

C&D Canal

Oldmans Creek

Christina River

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-15c

LOCATION OF SEDIMENT SAMPLING STATIONSLOWER STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDY

Legend

FIGURE

4-15c

LOCATION OF SEDIMENT SAMPLING STATIONSBASED ON REGIONAL SURVEYS

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

LOCATION OF SEDIMENT SAMPLING STATIONS FORTHE DELAWARE RIVER AND ITS TRIBUTARIES

BASED ON REGIONAL SURVEYSFIGURE

4-17c

Page 189: Characterization of Ecological Stressors in the Delaware Estuary

Trenton

Rancocas Creek

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-16a

LOCATION OF WATER SAMPLING STATIONSUPPER STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDYLegend

FIGURE

4-16a

LOCATION OF WATER SAMPLING STATIONS BASEDON REGIONAL SURVEYS

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer LOCATION OF WATER SAMPLING STATIONS FOR THEDELAWARE RIVER AND ITS TRIBUTARIES BASED ON

REGIONAL SURVEYSFIGURE

4-18a

Page 190: Characterization of Ecological Stressors in the Delaware Estuary

Camden

Philadelphia

Schuylkill River

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-16b

LOCATION OF WATER SAMPLING STATIONSMIDDLE STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDYLegend

FIGURE

4-16b

LOCATION OF WATER SAMPLING STATIONS BASEDON REGIONAL SURVEYS

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile BufferLOCATION OF WATER SAMPLING STATIONS FOR THEDELAWARE RIVER AND ITS TRIBUTARIES BASED ON

REGIONAL SURVEYSFIGURE

4-18b

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Salem

Wilmington

C&D Canal

Oldmans Creek

Christina River

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-16c

LOCATION OF WATER SAMPLING STATIONSLOWER STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDYLegend

FIGURE

4-16c

LOCATION OF WATER SAMPLING STATIONS BASEDON REGIONAL SURVEYS

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile BufferLOCATION OF WATER SAMPLING STATIONS FOR THEDELAWARE RIVER AND ITS TRIBUTARIES BASED ON

REGIONAL SURVEYSFIGURE

4-18c

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Trenton

Rancocas Creek

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-17a

LOCATION OF TISSUE SAMPLING STATIONSUPPER STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDY

Legend

FIGURE

4-17a

Location of Tissue Sampling Stations Based onRegional Surveys

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

LOCATION OF TISSUE SAMPLING STATIONS BASEDON REGIONAL SURVEYS

LOCATION OF TISSUE SAMPLING STATIONS FOR THEDELAWARE RIVER AND ITS TRIBUTARIES BASED ON

REGIONAL SURVEYSFIGURE

4-19a

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Camden

Philadelphia

Schuylkill River

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-17b

LOCATION OF TISSUE SAMPLING STATIONSMIDDLE STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDY

Legend

FIGURE

4-17b

Location of Tissue Sampling Stations Based onRegional Surveys

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

LOCATION OF TISSUE SAMPLING STATIONS BASEDON REGIONAL SURVEYS

LOCATION OF TISSUE SAMPLING STATIONS FOR THEDELAWARE RIVER AND ITS TRIBUTARIES BASED ON

REGIONAL SURVEYSFIGURE

4-19b

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Salem

Wilmington

C&D Canal

Oldmans Creek

Christina River

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476

95

295

195

81

276176

Note:

DRAFT

FIGURE4-17c

LOCATION OF TISSUE SAMPLING STATIONSLOWER STUDY AREA, BASED ON REGIONAL SURVEYS

DELAWARE RIVER STUDY

Legend

FIGURE

4-17c

Location of Tissue Sampling Stations Based onRegional Surveys

Delaware River and Tributaries

Delaware River and Tributaries - 1 Mile Buffer

LOCATION OF TISSUE SAMPLING STATIONS BASEDON REGIONAL SURVEYS

LOCATION OF TISSUE SAMPLING STATIONS FOR THEDELAWARE RIVER AND ITS TRIBUTARIES BASED ON

REGIONAL SURVEYSFIGURE

4-19c

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FIGURE

4-18

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

DOCUMENTED OIL SPILLS IN THE

DELAWARE ESTUARY 1972-2004

SOURCE:

CORBETT (2004)

DRAFT

DOCUMENTED OIL SPILLS IN THEDELAWARE ESTUARY, 1972-2004

FIGURE

4-20

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FIGURE

4-19

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

TOTAL PAH CONCENTRATIONS IN SEDIMENTS FROM THE DELAWARE

ESTUARY

SOURCE:

COSTA AND SAUER (1994)

Note: Estuary regions are Lower (Stations 1-4), Middle (Stations 5-9), and Upper (Stations 10-16).

DRAFT

Units are in μg/kg (dry weight).

Notes:Upper Zone: Stations 10-16Middle Zone: Stations 5-9Lower Zone: Stations 1-4

Units are in ug/kg (dry weight)

Notes:Upper Zone: Stations 10-16Middle Zones: Stations 5-9Lower Zone: Stations 1-4DRBC River Zones designated in text.

Notes:Upper Zone: Stations 10-16Middle Zone: Stations 5-9Lower Zone: Stations 1-4DRBC River Zones designated in text.

FIGURE

4-21

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FIGURE

4-20

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

LPAH AND HPAH CONCENTRATIONS IN

SEDIMENTS OF THE DELAWARE ESTUARY

(DRY WEIGHT)

SOURCE:

HARTWELL ET AL. (2001)

DRAFT

Delaware River Contaminants - PAHs

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

LPAH AND HPAH CONCENTRATIONS INSEDIMENTS OF THE DELAWARE RIVER

(DRY WEIGHT)

LPAH AND HPAH CONCENTRATIONS IN SEDIMENTS OF THEDELAWARE ESTUARY

(DRY WEIGHT)

LPAH = LOW WEIGHT PAHsHPAH = HIGH WEIGHT PAHs

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.LPAH = Low Weight PAHsHPAH = High Weight PAHs

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.LPAH = Low Weight PAHsHPAH = High Weight PAHsDRBC River Zones designated in text.

FIGURE

4-22

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FIGURE

4-21

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

LOW WEIGHT PAH CONCENTRATIONS IN

SEDIMENTS OF THE DELAWARE ESTUARY

(DRY WEIGHT)

SOURCE:

HARTWELL ET AL. (2001)

DRAFT

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Delaware River Contaminants - Low Weight PAHs

LOW WEIGHT PAH CONCENTRATIONS INSEDIMENTS OF THE DELAWARE ESTUARY

(DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 31-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 31-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-23

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FIGURE

4-22

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

HIGH WEIGHT PAH CONCENTRATIONS IN

SEDIMENTS OF THE DELAWARE ESTUARY

(DRY WEIGHT)

SOURCE:

HARTWELL ET AL. (2001)

DRAFT

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Delaware River Contaminants - High Weight PAHs

HIGH WEIGHT PAH CONCENTRATIONS INSEDIMENTS OF THE DELAWARE ESTUARY

(DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-24

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FIGURE

4-23

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

VOLATILE ORGANIC COMPOUNDS DETECTED

IN SURFACE AND WELL WATER IN THE

DELAWARE RIVER BASIN

SOURCE:

FISCHER ET AL. (2004)

DRAFT

VOLATILE ORGANIC COMPOUNDS DETECTED IN SURFACEAND WELL WATER IN THE DELAWARE RIVER BASIN

FIGURE

4-25

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FIGURE

4-24

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

EXISTING PENTA-PCB LOADINGS COMPARED WITH TMDL VALUES

SOURCE:DRBC (2003a)

DRAFTFIGURE

4-26

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FIGURE

4-25

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

A

AND 1997 WET WEA

SOURCE:DRBC (2003b)

DRAFT

557-DAY PENTA-PCB LOADS BYSOURCE CATEGORY

557-DAY PENTA-PCB LOADS BYSOURCE CATEGORY

577-DAY PENTA-PCB LOADS BYSOURCE CATEGORY

Notes:CSOs = Combined Sewer Overflows

SOURCE:DRBC (2006b)

FIGURE

4-27

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FIGURE

4-27

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

TOTAL PCB CONGENER CONCENTRATION IN

TRIBUTARY SAMPLES DURING THE 1996 DRY

WEATHER SURVEY AND 1997 WET WEATHER SURVEY

SOURCE:

DRBC (1998)

DRAFT

FIGURE

4-28

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FIGURE

4-28

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HARTWELL ET AL. (2001)

SUMMED CONCENTRATIONS OF ALL MEASURED PCBs

(EXCLUDING PLANAR PCBs) AT STATIONS SAMPLED UNDER

NOAA'S 1997 NATIONAL STATUS AND TRENDS PROGRAM

(DRY WEIGHT)

DRAFT

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-29

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FIGURE

4-29

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

BURTON (1997)

PCBs IN SURFACE (0-3") AND

SUB-SURFACE (3-5") SEDIMENTS IN 1996

ERL = Effects Range-Low for total PCBs in marine and estuarine sediments = 22.7 ng/g

(Long and Morgan 1990); 33.8 ng/g = DNREC draft human health protection guideline.

DRAFT

ERL = Effects Range-Low for total PCBs in marine and estuarine sediments22.7 ng/g from Long and Morgan (1990)33.3 ng/g from DNREC draft human health protection guideline

PCBs IN SURFACE (0-3") AND SUB-SURFACE (3-5")SEDIMENTS COLLECTED IN THE DELAWARE RIVER, 1996

Notes:ERL = Effects Range-Low for total PCBs in marine and estuarine sediments22.7 ng/g from Long and Morgan (1990)33.3 ng/g from DNREC draft human health protection guidelineDRBC Zone 3: Stations 1-2DRBC Zone 4: Stations 3-5DRBC Zone 5: Stations 6-8DRBC Zone 6: Stations 9-15

FIGURE

4-30

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FIGURE

4-30

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

REINFELDER AND TOTTEN (2006)

PROFILES OF MERCURY, DDT, AND PCBs IN A

SEDIMENT CORE FROM WOODBURY CREEK,

NEW JERSEY

DRAFT

Notes:THg = Total Mercury

FIGURE

4-31

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FIGURE

4-31a

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

ASHLEY ET AL. (2004)

TOTAL PCBs IN FISH AND INVERTEBRATES

SAMPLED IN THE FALL (WET WEIGHT AND

LIPID-NORMALIZED WHOLE BODY, μG/KG)

DRAFT

FIGURE

4-32a

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FIGURE

4-31b

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

ASHLEY ET AL. (2004)

TOTAL PCBs IN FISH AND INVERTEBRATES

SAMPLED IN THE SPRING (WET WEIGHT AND

LIPID-NORMALIZED WHOLE BODY, μG/KG)

DRAFT

FIGURE

4-32b

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42321001/SF/TEMPLATE.cdr

FIGURE

4-32

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

ASHLEY ET AL. (2004)

ZONAL DIFFERENCES IN THE FRACTIONAL (NORMALIZED TO

TOTAL WET WEIGHT CONCENTRATIONS) CONTRIBUTION

FROM EACH HOMOLOGUE GROUP FOR FALL AND SPRING

COLLECTED CHANNEL CATFISH WHOLE BODY

DRAFT

ZONAL DIFFERENCES IN THE FRACTIONAL CONTRIBUTIONFROM EACH HOMOLOGUE GROUP FOR FALL AND SPRING

COLLECTED CHANNEL CHATFISH WHOLE BODY(NORMALIZED TO TOTAL WET WEIGHT CONCENTRATIONS)

FIGURE

4-33

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FIGURE

4-33

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

ASHLEY ET AL. (2004)

ZONAL DIFFERENCES IN PCB CONGENER 209 LIPID-NORMALIZED

CONCENTRATIONS FOR FALL AND SPRING COLLECTED CHANNEL

CATFISH AND WHITE PERCH (WHOLE BODY, μG/KG)

DRAFT

ZONAL DIFFERENCES IN PCB CONGENER 209 LIPID-NORMALIZED CONCENTRATIONS FOR FALL AND SPRING

COLLECTED CHANNEL CATFISH AND WHITE PERCH

Note:Fish concentrations in whole body samples.

ZONAL DIFFERENCES IN PCB CONGENER 209 LIPID-NORMALIZED CONCENTRATIONS FOR FALL AND SPRING

COLLECTED CHANNEL CATFISH AND WHITE PERCH

ZONAL DIFFERENCES IN PCB CONGENER 209CONCENTRATIONS FOR FALL AND SPRING COLLECTED

CHANNEL CATFISH AND WHITE PERCH (LIPID-NORMALIZED)

FIGURE

4-34

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FIGURE

4-34

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:DRBC (2003a)

PCB CONCENTRATIONS IN FILLET SAMPLES OF CHANNEL CATFISH COLLECTED FROM ZONES 2 THROUGH 5 OF THE DELAWARE ESTUARY FROM 1977 TO 2001 (WET WEIGHT)

DRAFTFIGURE

4-35

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FIGURE

4-35

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:DRBC (2003a)

PCB CONCENTRATIONS IN FILLET SAMPLES OF WHITE PERCH COLLECTED FROM ZONES 2 THROUGH 6 OF THE DELAWARE ESTUARY FROM 1969 TO 2002 (WET WEIGHT)

DRAFTFIGURE

4-36

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FIGURE

4-36

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

RIVA-MURRAY ET AL. (2003)

TEMPORAL TRENDS IN PCB CONCENTRATIONS IN

FISH NEAR TRENTON, NEW JERSEY, 1969-1998 (WET

WEIGHT, VARIOUS FILLET AND WHOLE BODY)

Fda = U.S. Food And Drug Administration Tolerance Level

Nas/Nae = National Academy Of Sciences And National Academy Of Engineering Wildlife Guideline Level (1973)

Nys = Wildlife Protection Criterion Used By New York State Department Of Environmental Conservation

Mrl = Minimum Reporting Level For American Eel Samples

DRAFT

Notes:FDA = U.S. Food And Drug Administration Tolerance LevelNAS/NAE = National Academy Of Sciences and National Academy of Engineering Wildlife Guideline Level (1973)NYS = Wildlife Protection Criterion Used by New York State Department Of Environmental ConservationMRL = Minimum Reporting Level For American Eel Samples

FIGURE

4-37

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FIGURE

4-37

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

COSTA AND SAUER (1994)

SEDIMENT DDx CONCENTRATIONS IN μG/KG DRY WEIGHT

ACROSS 16 STATIONS (WITH STATION 1 LOCATED AT THE

MOUTH OF THE DELAWARE BAY AND STATION 16 LOCATED

NORTH OF PHILADELPHIA)

DRAFT

Note (as specified in original source):Lower Zone: Stations 1-4Middle Zone: Stations 5-9Upper Zone: Stations 10-16

SEDIMENT DDx CONCENTRATIONS IN ug/kg DRY WEIGHTACROSS 16 STATIONS (WITH STATION 1 LOCATED AT THE

MOUTH OF THE DELAWARE BAY AND STATION 16 LOCATEDNORTH OF PHILADELPHIA)

SEDIMENT DDx CONCENTRATIONS ACROSS 16 STATIONS(WITH STATION 1 LOCATED AT THE MOUTH OF THE

DELAWARE ESTUARY AND STATION 16 LOCATED NORTH OFPHILADELPHIA)

Note:Lower Zone: Stations 1-4Middle Zone: Stations 5-9Upper Zone: Stations 10-16Stations locations as specified by zone in Costa and Sauer (1994)

Notes:Lower Zone: Stations 1-4Middle Zone: Stations 5-9Upper Zone: Stations 10-16DRBC River Zones designated in text.

FIGURE

4-38

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FIGURE

4-38

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HARTWELL ET AL. (2001)

SUMMED DDx CONCENTRATIONS IN SEDIMENTS

SAMPLED DURING NOAA'S 1997 NATIONAL

STATUS AND TRENDS PROGRAM (DRY WEIGHT)

DRAFT

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-39

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FIGURE

4-39

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HARTWELL ET AL. (2001)

CHLORINATED PESTICIDES

CONCENTRATIONS IN SEDIMENT (μG/KG DRY

WEIGHT) AT THE 1997 NS&T STATIONS

DRAFT

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

CLORINATED PESTICIDES CONCENTRATIONS IN SEDIMENTAT THE 1997 NOAA NATIONAL STATUS AND TRENDS

PROGRAM STATIONS (DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

CHLORINATED PESTICIDES CONCENTRATIONS INSEDIMENT AT THE 1997 NOAA NATIONAL STATUS AND

TRENDS PROGRAM STATIONS (DRY WEIGHT)

Notes:HCB = HexachlorobenzeneHCH = HexachlorocyclohexaneUpper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-40

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FIGURE

4-40

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HAUGE (1993)

REGIONS AND SAMPLING LOCATIONS FOR

BIOTA SAMPLING FROM 1988-1991 FOR

PESTICIDES AND PCBs

DRAFT

FIGURE

4-41

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FIGURE

4-42

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

FISCHER ET AL. (2004)

CONCENTRATIONS OF CHLORINATED PESTICIDES AND

PCBs IN SEDIMENT (DRY WEIGHT) AND FISH TISSUE

(WHOLE BODY, WET WEIGHT) BY LAND USE CATEGORY

DRAFT

CONCENTRATIONS, BY LAND USE CATEGORY, OFCHLORINATED PESTICIDES AND PCBs IN SEDIMENT AND

FISH TISSUE (WHOLE BODY)

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FIGURE

4-43

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

FRITHSEN ET AL. (1995)

METALS LOADINGS FROM POINT

SOURCES IN THE DELAWARE ESTUARY

Note: Loadings were estimated using NOAA's NCPDI database.

DRAFT

AS = Arsenic

Cd = Cadmium

Cr = Chromium

Cu = Copper

Fe = Iron

Hg = Mercury

Pb = Lead

Zn = Zinc

Notes:As = ArsenicCd = CadmiumCr = ChromiumCu = CopperFe = IronHg = MercuryPb = LeadZn = ZincLoadings were estimated using NOAA's National Coastal Pollutant Discharge Inventory (NCPDI) database.

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FIGURE

4-45DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

FRITHSEN ET AL. (1995)

DIRECT ATMOSPHERIC LOADINGS OF

METALS TO THE DELAWARE ESTUARY

Notes:

AS = Arsenic

Cd = Cadmium

Cr = Chromium

Cu = Copper

Fe = Iron

Hg = Mercury

Pb = Lead

Zn = Zinc

Notes:As = ArsenicCd = CadmiumCr = ChromiumCu = CopperFe = IronHg = MercuryPb = LeadZn = ZincLoadings were estimated using NOAA's National Coastal Pollutant Discharge Inventory (NCPDI) database.

FIGURE

4-44

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FIGURE

4-46

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

FRITHSEN ET AL. (1995)

ATMOSPHERIC LOADINGS OF METALS TO

THE DELAWARE ESTUARY VIA THE

WATERSHED

DRAFT

Notes:

AS = Arsenic

Cd = Cadmium

Cr = Chromium

Cu = Copper

Fe = Iron

Hg = Mercury

Pb = Lead

Zn = Zinc

Notes:As = ArsenicCd = CadmiumCr = ChromiumCu = CopperFe = IronHg = MercuryPb = LeadZn = ZincLoadings were estimated using NOAA's National Coastal Pollutant Discharge Inventory (NCPDI) database.

FIGURE

4-45

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FIGURE

4-47

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SUMMED SEDIMENT CONCENTRATIONS (DRY WEIGHT) OF

METALS IN THE DELAWARE ESTUARY (NOTE: SUMS

EXCLUDE ALUMINUM, IRON, AND MANGANESE)

SOURCE:

HARTWELL ET AL. (2001)

DRAFT

Note:Add where stations are and what metals are included

Summed metals concentrations for silver, arsenic, cadmium, chromium, copper, mercury, nickel, lead, antimony, selenium, tin, thallium, and zinc.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Summed metals concentration for silver, arsenic, cadmium, chromium, copper, mercury, nickel, lead,antimony, selenium, tin, thallium and zinc.

SUMMED SEDIMENT CONCENTRATIONS OFMETALS IN THE DELAWARE ESTUARY

(DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Summed metals concentrations for silver, arsenic, cadmium, chromium, copper, mercury, nickel, lead, antimony,selenium, tin, thallium and zinc.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

Summed metals concentrations for silver, arsenic, cadmium, chromium, copper, mercury, nickel, lead, antimony,selenium, tin, thallium and zinc.

FIGURE

4-46

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FIGURE

4-48

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

REINFELDER AND TOTTEN (2006)

VERTICAL PROFILE OF MERCURY IN

SEDIMENT (μG/KG, DRY WEIGHT) FROM

OLDMANS CREEK, NEW JERSEY

DRAFT

VERTICAL PROFILE OF MERCURY IN SEDIMENTFROM OLDMANS CREEK, NEW JERSEY

(DRY WEIGHT)

FIGURE

4-47

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FIGURE

4-49

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

RANGE OF TOTAL PHOSPHORUS

CONCENTRATIONS IN THE DELAWARE ESTUARY

BY RIVER MILE, JULY-SEPTEMBER OF 1998-2003

DRBC BOAT RUN PROGRAM, AS

PRESENTED IN SANTORO (2004)

DRAFT

FIGURE

4-48

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FIGURE

4-50

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

RANGE OF AMMONIA NITROGEN (NH3 AND NH4-N)

CONCENTRATIONS IN THE DELAWARE ESTUARY,

JULY-SEPTEMBER OF 1998-2003

DRBC BOAT RUN PROGRAM, AS

PRESENTED IN SANTORO (2004)

DRAFT

RANGE OF AMMONIA AND NITROGEN (NH3 AND NH4-N)CONCENTRATIONS IN THE DELAWARE ESTUARY, JULY-

SEPTEMBER OF 1998-2003

FIGURE

4-49

RANGE OF TOTAL NH3 AND NH4CONCENTRATIONS IN THE DELAWARE

ESTUARY, JULY-SEPTEMBER OF 1998-2003

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FIGURE

4-51

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

SANTORO (2004)

DISTRIBUTION OF NITRITE-NITROGEN IN

SURFACE WATER OF THE DELAWARE

ESTUARY FROM 1998-2003

DRAFT

FIGURE

4-50

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FIGURE

4-55DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HARTWELL ET AL. (2001)

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS

(TETRA-, TRI-, DI,- AND MONO-BT) IN SEDIMENT (DRY

WEIGHT) AT DELWARE BAY SAMPLING STATIONS

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS(TETRA-,TRI-,DI,- AND MONO-BT) IN SEDIMENT AT

DELAWARE ESTUARY SAMPLING STATIONS (DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-51

SOURCE:SHARP (PERSONAL COMMUNICATION)

Notes:1 mg N/L = 70 ug-at N/L, 1 mg P/L = 32 ug-at P/L

MONTHLY-WEIGHTED ANNUAL AVERAGENUTRIENT CONCENTRATIONS IN THE DELAWARE

ESTUARY FROM 1986-1988

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FIGURE

4-52

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

SANTORO (2004)

Summer Dissolved OxygenThroughout Delaware Estuary

(

0

1

2

3

4

5

6

7

8

9

5 25 45 65 85 105 125River Mile

Dis

so

lve

d o

xy

ge

n (

mg

/L)

1967

1980

1998

1999

2000

2001

2002

2003

Saturation

SUMMER (JULY - SEPTEMBER) DISSOLVED

OXYGEN CONCENTRATIONS BY RIVER MILE IN

THE DELAWARE ESTUARY, 1967-2003

DRAFT

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FIGURE

4-55DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HARTWELL ET AL. (2001)

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS

(TETRA-, TRI-, DI,- AND MONO-BT) IN SEDIMENT (DRY

WEIGHT) AT DELWARE BAY SAMPLING STATIONS

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS(TETRA-,TRI-,DI,- AND MONO-BT) IN SEDIMENT AT

DELAWARE ESTUARY SAMPLING STATIONS (DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

150

FIGURE

4-53

SOURCE:SHARP (PERSONAL COMMUNICATION)

DISSOLVED OXYGEN SATURATION ALONG THEDELAWARE ESTUARY FROM 1990-2003

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FIGURE

4-53

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

ASHLEY ET AL. (2006)

CONCENTRATIONS OF TOTAL PCBs AND TOTAL PBDEs

(DRY WEIGHT AND ORGANIC CARBON-NORMALIZED) FOR

SEDIMENT SAMPLES COLLECTED IN 2002 FROM FOUR

LOCATIONS IN THE DELAWARE ESTUARY

DRAFT

CONCENTRATIONS OF TOTAL PCBs AND TOTAL PBDEs FORSEDIMENT SAMPLES COLLECTED IN 2002 FROM FOUR

LOCATIONS IN THE DELAWARE ESTUARY

FIGURE

4-54

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FIGURE

4-54

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

ASHLEY ET AL. (2006)

TOTAL PBDE CONCENTRATIONS REPORTED ON A WET

WEIGHT AND LIPID NORMALIZED BASIS FOR AMERICAN

EEL FILLETS GROUPED ACCORDING TO COLLECTION

SITE (μG/KG)

Note: Locations go north to south starting in the non-tidal Delaware River (DE Water Gap)

ending at tributaries near the mouth of Delaware Bay (DE Bay Tribs).

DRAFT

TOTAL PBDE CONCENTRATIONS REPORTED FOR AMERICANEEL FILLETS GROUPED ACCORDING TO COLLECTION SITE

FIGURE

4-55

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FIGURE

4-55DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

HARTWELL ET AL. (2001)

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS

(TETRA-, TRI-, DI,- AND MONO-BT) IN SEDIMENT (DRY

WEIGHT) AT DELWARE BAY SAMPLING STATIONS

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Continental Shelf: Stations 62-73

SUMMED CONCENTRATIONS OF BUTYL TIN COMPOUNDS(TETRA-,TRI-,DI,- AND MONO-BT) IN SEDIMENT AT

DELAWARE ESTUARY SAMPLING STATIONS (DRY WEIGHT)

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.

Notes:Upper Zone: Stations 1-15Transition Zone: Stations 16-31Lower Zone: Stations 32-61Stations 62-73 are located outside of the Delaware Estuary along the Atlantic continental shelf.DRBC River Zones designated in text.

FIGURE

4-56

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FIGURE

4-56

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

FOFONOFF AND RUIZ (2003)

VECTORS OF NIS

TRANSPORT-DELAWARE BAY

DRAFT

Note: NIS = sodium iodide symporterNote: NIS = Nonindigenous Species

VECTORS OF NIS TRANSPORT-DELAWAREESTUARY

VECTORS OF NONINDIGENOUS SPECIESTRANSPORT-DELAWARE ESTUARY

Note:NIS = Nonindigenous Species

FIGURE

4-57

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FIGURE

4-57

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

DELAWARE DNREC (1999)

PHRAGMITES DOMINATED COASTAL

WETLANDS OF DELAWARE

DRAFT

FIGURE

4-58

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FIGURE

4-58DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

WHITMORE (2005)

PERCENT COMPARISON OF THE RECREATIONAL AND

COMMERCIAL HARVEST, IN POUNDS, FOR SELECTED

SPECIES LANDED IN DELAWARE, 2004

FIGURE

4-59

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FIGURE

4-59

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:KILLAM AND RICHKUS (1992)

DRAFT

SYNTHESIZED ESTUARY SPECIFIC AMERICAN SHAD HARVEST

SYNTHESIZED ESTUARY-SPECIFICAMERICAN SHAD HARVEST

FIGURE

4-60

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FIGURE

4-60DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

KILLAM AND RICHKUS (1992)

SYNTHESIZED ESTUARY SPECIFIC

STURGEON HARVEST

SYNTHESIZED ESTUARY-SPECIFICSTURGEON HARVEST

FIGURE

4-61

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FIGURE

4-61DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

KILLAM AND RICHKUS (1992)

SYNTHESIZED ESTUARY SPECIFIC

MENHADEN HARVEST

SYNTHESIZED ESTUARY-SPECIFICATLANTIC MENHADEN HARVEST

FIGURE

4-62

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FIGURE

4-62DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

KILLAM AND RICHKUS (1992)

SYNTHESIZED ESTUARY SPECIFIC

STRIPED BASS HARVEST

SYNTHESIZED ESTUARY-SPECIFICSTRIPED BASS HARVEST

FIGURE

4-63

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FIGURE

4-63DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

SANTORO (2004)

RECREATIONAL STRIPED BASS

HARVEST, 1982-2002

FIGURE

4-64

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FIGURE

4-64DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

KILLAM AND RICHKUS (1992)

SYNTHESIZED ESTUARY SPECIFIC

WEAKFISH HARVEST

SYNTHESIZED ESTUARY-SPECIFICWEAKFISH HARVEST

FIGURE

4-65

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FIGURE

4-65

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

KILLAM AND RICHKUS (1992)

SYNTHESIZED ESTUARY SPECIFIC EEL

HARVEST

DRAFT

SYNTHESIZED ESTUARY-SPECIFIC EELHARVEST

FIGURE

4-66

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FIGURE

4-66

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

PARTNERSHIP FOR THE DELAWARE

ESTUARY (2002)

NEW JERSEY OYSTER HARVEST FROM

THE DELAWARE ESTUARY, 1875 - 2000

DRAFT

FIGURE

4-67

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FIGURE

4-67

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

KILLAM AND RICHKUS (1992)

SYNTHESIZED ESTUARY SPECIFIC

BLUE CRAB HARVEST

DRAFT

FIGURE

4-68

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FIGURE

4-68DRAFT

E.I. DuPONT de NEMOURS AND COMPANYWILMINGTON, DE

DELAWARE RIVER STUDY

SOURCE:

DELAWARE BAY BLUE CRAB LANDINGS

(1000s POUNDS) BY STATE, 1972 - 2000

SANTORO (2004)

Notes:Landings based on conversion of 40 lbs/ bushel1973 landings do not include dredge landings

FIGURE

4-69