TMDLs for PCBs for the Delaware River Estuary · TMDLs for PCBs for the Delaware River Estuary Thomas J. Fikslin, Ph.D., Manager Modeling, Monitoring and Assessment Branch. Delaware

TMDLs for PCBsfor the Delaware River Estuary

Thomas J. Fikslin, Ph.D., Manager Modeling, Monitoring and Assessment Branch

Delaware Estuary

2

Background

Delaware Estuary is 133 miles long and is bordered by DE, NJ and PA

1998 – All three states listed the Delaware Estuary as impaired requiring the development of TMDLs.

Spring 2000 – DRBC designated the lead agency to develop the TMDLs for PCBs by the court-ordered deadline of Dec. 15, 2003.

Major boundaries: Delaware River at Trenton, NJ; Schuylkill River; C&D Canal; and the Ocean.

Point sources: 94 industrial and municipal facilities, CSOs, and MS4s.

Tributaries: 22 Contaminated sites: ~ 50 Air flux and deposition.

3

4

Homolog Distribution in Estuary Zones - 2003White Perch

0.0

50.0

100.0

150.0

200.0

250.0

Mono Di Tri Tetra Penta Hexa Hepta Octa Nona Deca

PCB Homologs

Nan

ogra

ms

per g

ram

(wet

wei

ght)

Zone 2 Zone 3 Zone 4 Zone 5

5

Median Ambient PCB ConcentrationsStage 1 - 2002 to 2003

Tetra through Hexa Homolog Distribution

0

200

400

600

800

1000

1200

1400

2 3 4 5 6

Estuary Zone

pico

gram

s pe

r lite

r (pg

/l)

Tetra Penta Hepta Hexa

Water QualityCriterion - 16 pg/L

6

Principal Mass Loadings and Fluxes

Contaminated Site Loads

Upstream Boundary LoadDelaware River at Trenton, NJ

SedimentFlux

AtmoshphericWet / Dry

Deposition

AtmoshphericGas phase

flux

Upstream Boundary LoadSchuylkill River

Non-Point Source LoadsTributary Loads

Point Discharge Loads

Sediment

C&D Canal(tidal boundary)

Ocean BoundaryMouth of Delaware Bay

CSOs

LEGEND

External Loads(forcing functions)

Fluxes and tidal boundaries

7

Themes Importance of the Water Quality Target Importance of Source Identification and

QuantitationNeed for a Model Importance of the Sediment Reservoir Developing Complex TMDLs Staged TMDL Development for the

Delaware Estuary Non-numeric permit requirements

8

TMDLs must be based upon the most stringent water quality criteria applicable to the receiving water in order for the designated uses of the water body to be met.

In interstate waters like the Delaware Estuary, inconsistent uses and criteria complicate the identification of the most stringent criterion.

In the Delaware Estuary, criteria for the protection of human health and wildlife were potentially the most restrictive.

Importance of theTMDL Target

9

Water Quality Criteria

Zones 2 & 3 Zone 4 & Upper Zone 5

Rest of Zone 5

Existing DRBC Criteria

44.4 pg/l 44.8 pg/l 7.9 pg/l

Existing PCB criteria creates a critical point in Zone 5. This has significant effects on the available assimilative capacity (the TMDLs).

10

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 20 40 60 80 100 120 140

River Mile

Con

cent

ratio

n, p

g/L

Median_99_100th year water column target

Zone 6 Zone 5 Zone 4 Zone 3 Zone 2

Penta-PCB Water Column Concentrations at TMDL Loads, 100 year simulation

11

Water Quality Criteria DRBC staff has developed a revised water

quality criterion of 16 pg/L that is applicable to all zones.

This criterion utilizes the 2000 U.S. EPA methodology for deriving human health criteria, and incorporates: the upper bound estimate of the cancer potency

factor of 2.0 (mg/KG)/day, site-specific fish consumption rates, and a site-specific bioaccumulation factor.

12

PCB Criteria and TMDLs in Delaware Estuary

0

10

20

30

40

50

0 20 40 60 80 100 120 140

River miles from the mouth of the bay

conc

entr

atio

n, p

g/L

Existing Criteria TMDL_Stage_1 Proposed Criteria TMDL_Stage_2(?)

44.4 pg/L44.8 pg/L

7.9 pg/L

16 pg/L

Unused assimilative

capacity

Fully utilize assimilative

capacity

Why develop a Model?ì Gain understanding:

Determine PCB load-response relationships.

Determine principal controlling processes.

Address management questions:Determine PCB TMDL for each zone. Allocate TMDLs among sources.Assess the impact of load reduction

strategies. 14

Delaware River PCB Model (DELPCB)

Modified version of DYNHYD5/TOXI5 EPA-supported and widely used for toxic

chemical TMDLs and contaminated sediments.Model formulations/code extensively tested and

assessed with observations at numerous sites. Builds upon modeling work at other sites:

Green Bay Mass BalanceStudyUpper Hudson River RI/FSFox River RI/FS

Kalamazoo RiverRI/FSNew York Harbor

CARP Model15

Delaware River PCB Model (DELPCB)

Represents water column and sediments One-dimensional in longitude87 spatial segments

Time-variable HydrodynamicsTidal heightsChloride mass balance

Organic carbon sorbent dynamicsParticulate carbon (biotic and detrital)Dissolved organic carbon

Penta PCB homolog 16

Short-term Calibration for penta-CB

17

1

10

100

1,000

10,000

1970 1975 1980 1985 1990 1995 2000 2005

Time

Tota

l-PC

B [n

g/L]

Model 80%Model 50%Model 20%Data

Decadal Scale Calibrationfor penta-PCB

18

Key Findings The principal sources of PCB loadings are non-

point source runoff, point sources and the mainstem Delaware River.

The flux of PCBs between the gas phase in the atmosphere and dissolved PCBs in the water is a significant process affecting the achievement of the TMDLs.

PCB loadings at head of tide (Trenton) have a significant influence in the tidal Delaware River.

Water column PCBs are strongly influenced by loadings and sediments. 19

Summary points

Model for PCBs is developed and calibrated.Model is scientifically credible. Collaboration with Delaware Estuary TMDL

CoalitionAvoided adversarial process and a competing model

Model was used to develop Stage 1 PCB TMDL, but Stage 2 is necessary to address uncertainties.

Model can be extended to other contaminantsand to other watersheds.

20

Source Identification & Quantitation

Identifying and quantifying PCB sources using congener-specific analytical methods has several benefits:Allows prioritization of sources for load reductions.Reduces the uncertainty in model inputs.Permits fingerprinting of sources.Allows permittees/site owners to track the

effectiveness of pollutant minimization activities.

21

Penta-PCB Load by Source CategorySept 2001 through March 2003

9.22

6.56

5.26

4.00 3.903.47

2.34 2.19

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

Non-PointSource Runoff

PointDischarges

Delaware atTrenton

Schuylkill ContaminatedSites (revised)

All OtherTributaries

Atmosphericwet and drydeposition

CSOs

Source Category

577-

day

Pent

a PC

B L

oad

(kg)

22

Cumulative 2005-06 Penta-PCB LoadingsNPDES Discharges (Total n=128)

48

57

63

69

7580

8486

88 89 91 92 93 94 94 95 96 96 97 97 97 97 98 98 98

20

30

40

50

60

70

80

90

100

110

Val

ero

Ref

inin

g

PWD

-NE

City

of W

ilmin

gton

U.S

. Ste

el

PWD

-SW

CC

MU

A

AM

TRA

K R

ace

St./P

enn

Coa

ch

PWD

-SE

Tren

ton

Dup

ont-C

ham

berW

orks

PQ C

orpo

ratio

n

Met

ro M

achi

ne

Dup

ont-R

epau

no

Dup

ont-C

ham

berW

orks

Ham

ilton

Tow

nshi

p

PQ C

orpo

ratio

n

Will

ingb

oro

Mun

icip

al U

tiliti

esA

utho

rity

Mor

risvi

lle W

WTP

PQ C

orpo

ratio

n

DEL

CO

RA

Low

er B

ucks

Cou

nty

Mun

icip

alA

utho

rity

Solu

tia

GC

UA

Del

ran

Sew

erag

e A

utho

rity

Dup

ont-R

epau

no

Perc

ent (

%)

N = 16

23

Establishing TMDLsTMDLs are estimates of the loadings of each

of the PCB homologs that can enter the estuary and still meet the current water quality criteria. They are projected loadings from all sources based upon assumptions called design conditions.Since current concentrations of PCB homologs

are 500 times higher than the water quality criteria, the TMDLs and associated individual WLAs and LAs will be proportionately less.

24

Allocate 5% of each of the zone TMDLs to a margin of safety (MOS).Allocate to the contaminated sites category.Allocate the remainder of the zone TMDLs

to a WLA portion and a LA portion based upon the current percentage contribution for each of the source categories to each zone during the period February 1, 2002 to January 31, 2003.

Summary of Approach for Stage 1

25

Using the estuary-wide ratio of penta-PCBs to Total PCBs from ambient data collected in the Delaware Estuary, the zone-specific, penta-PCB TMDLs were scaled up using a fixed ratio of 1:4 to calculate the TMDL.

Summary of Approach for Stage 1

26

Ratio of Penta-PCBs toTotal PCBs in Ambient Samples

0.15

0.20

0.25

0.30

0.35

2 3 4 5

Zones

Pent

a to

Tot

al P

CB

Rat

io

27

Penta PCB Water Target

Assimilative Capacity by Sedimentation0.500 pg/L

1.975 pg/L Usable Assimilative

Capacity

0.183 pg/L

2.292pg/L

Trenton

Schuylkill

Zone 2

Zone 3

Zone 4

Zone 5

Contribution by the Mouth of the Bay and C&D Canal

MOS

C. Site

Open BC

Allocation of the Assimilative Capacityat the Critical Location

28

Stage 1 TMDLs forTotal PCBs

Estuary Zone TMDL WLA LA MOSmg/day mg/day mg/day mg/day

Zone 2 257.4 5.0 239.5 12.9

Zone 3 17.8 4.9 12.0 0.9

Zone 4 56.7 5.2 48.7 2.8

Zone 5 48.1 13.3 32.4 2.4

Sum 380.0 28.3 332.6 19.0

Approach for EstablishingStage 2 TMDLsThe approach for establishing Stage 2 TMDLs

is expected to be different than that used in Stage 1.Some of the reasons for this are:A revised human health criteria for total PCBs has

been developed that does not produce a sharp transition between zones.

An alternative allocation procedure for both the aggregate WLAs and LAs, and the individual WLAs and LAs that is more equitable will be needed. 30

Approach for EstablishingStage 2 TMDLs

TMDLs for total PCBs for each zone will be the sum of the TMDLs for four homologs without extrapolation from Penta-PCBs.

Alternative source reduction strategies thatresult from either the PCB Minimization Plans required in Stage 1 or the efforts of the PCB Implementation Committee will need to be considered , where appropriate, in allocating the zone TMDLs.

31

Progress to Date

DRBC implemented the Stage 1 TMDLs by requiring point sources to conduct additional monitoring using low level techniques (Method 1668A). The results of this monitoring have been submitted and assessed.

DRBC passed regulations in May 2005 requiring point source dischargers to submit and implement PMPs. 42 dischargers are initially required to submit the plans.

Regulations can be applied to any point and non-point source that the Commission determines has an “adverse impact” on the water resources of the Basin.

32

Achieving Water Quality Criteria

Reductions in PCB loadings will not immediately result in lower ambient water concentrations or in reduced tissue levels of PCBs in resident fish species.

This is due to the continuing flux of PCBs from the sediments to the water column. As solids uncontaminated by PCBs settle to the bottom, this flux will ultimately reach equilibrium with the water column.

33

100 year projection with all sources set to zero

0.1

1

10

100

1000

10000

2001 2011 2021 2031 2041 2051 2061 2071 2081 2091 2101

Years

Tot

al P

CB

Con

cntr

atio

n (p

g/L

)

Zone 3 Zone 2 Proposed Criteria

June 2021

June 2031

34

Achieving Water Quality Criteria

Reductions in PCB loadings will not immediately result in lower ambient water concentrations or in reduced tissue levels of PCBs in resident fish species.

This is due to the continuing flux of PCBs from the sediments to the water column. As solids uncontaminated by PCBs settle to the bottom, this flux will ultimately reach equilibrium with the water column.

A long-term strategy for permitting point source discharges and addressing non-point sources such as contaminated sites and air sources is needed to ensure continued progress in reducing PCBs.

35

Contact Information:

[email protected](609) 883-9500, ext.253

Information on the TMDLs, model development, sampling and analytical information, and PMP requirements and resources are available on the DRBC website at:

www.drbc.net36

Stage 2 Implementation Requirements

Build upon the monitoring and PMP requirements of Stage 1 TMDLs.

Incorporate the concept of an Action Level.• Purpose - to elicit a prompt response to elevated

PCB concentrations above those achieved.• Establish duration and magnitude of elevated

concentrations.• Document actions taken and return to PCB

concentrations previously observed, or proposed actions to be included in a revised PMP.

NPDES Permitting Strategy Two Response Levels Approach

• Based upon the last 10 data points collected under normal operating conditions.

• Monitoring Trigger Level (MTL) - based upon 95th confidence interval of the median. Objective is to obtain additional monitoring data given the

low frequency of permit monitoring required. Permittee has primary responsibility – Reporting to DRBC

required.

• Action Level - based upon maximum projected effluent concentration. Objective is to require monitoring and submittal of a report. Permittee and DRBC/State permitting agency share

responsibility.

46 % reduction

10 Dischargers Representing 90% of Point Source PCB Loadings in the Estuary

42,852

23,058

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

2005 Point Source Load Current Point Source Load

mg/d

Incremental Progress Reductions in Loadings from Non-Point

SourcesT Removal of ~40,000 lbs. of PCBs from tidally-influenced

wetland adjacent to tributary creek.T Removal of ~8,000 lbs. from NPL industrial site.T Inventory of Superfund sites - DelTriP

http://www.state.nj.us/drbc/about/public/publications/deltrip.html

In 2013, DE and NJ relaxed fish consumption advisories to 1 meal per year in Zone 5.

Ambient water concentrations did not change significantly as expected.