REM IV Remedial Planning Activities at Selected Uncontrolled Hazardous Waste Sites-Zone SFUND RECORDS CTR 0217-00024 SFUND RECORDS CTR 88004692 ^ Environmental Protection Agency ^If!^ Hazardous Site Control Division Contract No. 68-01-7251 TECHNICAL MEMORANDUM RESULTS OF THE PGA SOILS INVESTIGATION PHOENIX-GOODYEAR AIRPORT RI/FS WA No. 30-9L19.0 October 5, 198 7 a^HILL Black & Veatch ICF PRC Ecology and Environment
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REM IV Remedial Planning Activities at Selected Uncontrolled Hazardous Waste Sites-Zone
SFUND RECORDS CTR
0217-00024
SFUND RECORDS CTR
88004692
^ Environmental Protection Agency ^ I f !^ Hazardous Site Control Division
Contract No. 68-01-7251
TECHNICAL MEMORANDUM RESULTS OF
THE PGA SOILS INVESTIGATION
PHOENIX-GOODYEAR AIRPORT RI/FS
WA No. 3 0 - 9 L 1 9 . 0
O c t o b e r 5 , 198 7
a^HILL Black & Veatch ICF PRC Ecology and Environment
TECHNICAL MEMORANDUM RESULTS OF
THE PGA SOILS INVESTIGATION
PHOENIX-GOODYEAR AIRPORT RI/FS
WA No. 30-9L19.0
October 5, 1987
NONDISCLOSURE STATEMENT
This document has been prepared for the U.S. Environmental Protection Agency under Contract No. 68-01-7251. The material contained herein is not to be disclosed to, discussed with, or made available to any person or persons for any reason without the prior express approval of a responsible official of the U.S. Environmental Protection Agency.
Page
CONTENTS
Introduction Purpose and Scope Selection of Analytical Parameters Selection of Sampling Locations
9 Pesticide Concentrations in Sediments Derived 30 from the Airport Drain Ditch
10 Metal Concentrations from the GAC Sludge 32 Drying Beds
11 Chromium Concentrations from GAC Sludge 35 Drying Bed No. 1
12 Chromium Concentrations from GAC Sludge 36 Drying Bed No. 2
13 Chromium Concentrations from Former Sewage 38 Treatment Facility
14 Chromium Concentrations Along the Course of 38 the Airport Drain Ditch near the Outfall of Drain 001
15 Chromium Concentrations from the Former Paint 3 9 Tent Area
16 Chromium Concentrations from the Hangar Apron 39 Area
Follows FIGURES Page
1 Site Location Map ^
2 General Soil Sampling Areas of PGA (located at end of report)
3 VOC Boring Locations and Pesticide Sampling Locations of Sediments from the Airport Drain Ditch (located at end of report)
4 Soil Sampling Locations Near the Airport ( Hangars and Former Paint Tent
5 Pesticide Sampling Locations of Sediments Derived from the Airport Drainage Ditch
6 Soil Sampling Locations at the Former GAC ! Sludge Drying Beds
RD/R91/043-3
CONTENTS (Continued)
Follows FIGURES (continued) Page
7 Soil Boring Locations at the Former PGA 8 Sewage Treatment Facility
8 Soil Boring Locations in the Former Airport 8 Drain Ditch Near the Outfall of Drain 001
9 Background Soil Sampling Locations (located at end of report)
RD/R91/043
RD/R91/043-4
TECHNICAL MEMORANDUM
PREPARED BY:
DATE:
RE:
PROJECT:
DISTRIBUTION;
John Lucero and Jess Brown, CH2M HILL/RDD
October 5, 1987
Results of the PGA Soils Investigation
W63600.FT
EPA RPM—Jeff Rosenbloom PGA Technical Committee Nancy Lindsay, U.S. EPA, Region IX Randall Kaltreider, U.S. EPA, Headquarters CH2M HILL QA Reviewers—Terry Foreman/LAO, Mike Kemp/GNV, and Bob Schilling/RDD Site Manager—John Lucero/RDD Peter Mock/CH2M HILL, PHX Fritz Carlson/CH2M HILL, RDD Mike Smith/CH2M HILL, RDD Jess Brown/CH2M HILL, RDD Steve Hahn/CH2M HILL, SFO Jane Fisher/CH2M HILL, SFO Steve Franks/CH2M HILL, RDD Vicki Kohonoski/CH2M HILL, WDC Beth Baruth/CH2M HILL, DEN Don Huff/Black & Veatch
INTRODUCTION
This technical memorandum summarizes the results obtained from the analyses of soil samples collected from various locations at the Phoenix Goodyear Municipal Airport (airport) and from the former Goodyear Aerospace Corporation (GAC) facility from June 23 to July 28, 1987. This memorandum also summarizes deviations from field or laboratory procedures described in the Phoenix-Goodyear Airport Soil Sampling Plan.
These data will be used for interpreting the degree and extent of contamination, and to assess the potential adsorption or mobility of the compounds of interest. The results of these interpretations will be discussed in a future soils interpretation technical memorandum.
CH2M HILL. Soil Sampling Plan Phoenix-Goodyear Airport RI/FS. Prepared for U.S. EPA, Toxics and Waste Management Division, REM/FIT, Contract No. 68-01-6692. June 29, 1987,
RD/R91/040
The Phoenix-Goodyear Airport Superfund site (PGA) is located in the Salt River Valley approximately 20 miles west of Phoenix, Arizona. The study area encompasses approximately 42 square miles of agricultural, industrial, and municipal property within the Cities of Goodyear, Avondale, and Phoenix (Figure 1). The climate is characterized by long, hot summers and short, mild winters. The average annual precipitation is approximately 7.5 inches per year. Vegetation in nonirrigated undeveloped areas is very sparse, but there are many areas of irrigated agricultural lands to the north, west, and east of the study area.
PURPOSE AND SCOPE
The primary objective of the PGA soils investigation was to define the vertical extent of the contaminants that had been identified at the PGA site during previous investigations. The sampling effort was also intended to satisfy the data needs to develop a detailed work plan outline for a future feasibility study.
Specific objectives of the PGA soils investigation were as follows:
o Assess the vertical extent and degree of contamination by volatile organic compounds (VOC's) at the airport and GAC.
o Assess the vertical extent of contamination of chromium at suspected source areas.
o Collect an adequate number of soil samples from representative soil taxa near the PGA site to quantify background contaminant concentrations.
o Assess if the site's soils contain contaminant concentrations in excess of the Arizona Department of Environmental Quality's (ADEQ, formerly the Arizona Department of Health Services) suggested health-based soil action levels.
o Examine other soil properties that may influence the adsorption or mobility of soil contaminants.
o Assess the degree of contamination by pesticides at suspected locations at the airport.
2 Ecology and Environment. Source Verification Field Investigation. Prepared for U.S. EPA, Toxics and Waste Management Division, REM/FIT, Contract No. 68-01-6692. January 31, 1986.
RD/R91/040
F I G U R E 1
SITE LOCATION MAP
P H O E N I X - G O O D Y E A R AIRPORT SOILS I N V E S T I G A T I O N
W 6 3 6 0 0 . F T O C T O B E R 1 9 8 7
o Assess whether the potential soil contamination is a continuing source of groundwater contamination.
The scope of this field investigation included the following elements:
o The collection of soil samples for VOC analysis from 22 soil boring locations situated at the airport and the former GAC facility
o The collection of soil samples for total chromium analyses from 15 soil boring locations located at the airport
o The excavation and collection of soil samples from 14 backhoe test pits plus the collection of 8 composite sediment samples for pesticide analyses
o The collection of soil samples for total chromium and additional metals analyses from 12 backhoe test pits at the former GAC facility
o The collection of representative background soil samples from eight backhoe test pits for pesticides, chromium, and additional metals analyses
For ease of discussing sampling locations and to provide an overview of the sampling areas, refer to Figures 2 and 9, located at the end of the report.
SELECTION OF ANALYTICAL PARAMETERS
The analytical parameters selected were based on the findings of previous investigations conducted at the airport and the former GAC facility. Previous investigations identified a number of VOC's, EPA priority pollutant metals, and pesticides. The soil contaminants that had been previously identified at the site and were suspected of exceeding the ADEQ suggested health-based soil action limits are trichloroethene (TCE), isomers of dichloroethene (1,1-DCE and 1,2-DCE), 1,1,1-trichloroethane (1,1,1-TCA), perchloroethene (PCE), 1,l-dichloro-2,2-bis[p-chlorophenyl]-ethene (4-DDE'], l,l,l-dichloro-2,2-bis[chlororphenyl]-ethane (4-DDT'), aluminum, and chromium.
Table 1 shows the health-based cleanup levels for contaminants in soils suggested by ADEQ.
Other organic compounds that had been previously identified in groundwater samples and were evaluated during this investigation were chloroform, carbon tetrachloride, and methylene chloride. Vinyl chloride was also added to the list of
ADEQ did not provide information on 1,1,1-TCA and PCE action limits.
organic analytical parameters because it is a degradation product of TCE. Additional metals selected for analysis were arsenic, barium, cadmium, copper, lead, mercury, manganese, nickel, and zinc. These additional metals were selected to gather the data necessary to evaluate potential exposure levels for the PGA Public Health Endangerment Assessment.
The analytical parameters are grouped into four analytical suites:
o Suite 1—VOC's o Suite 2—Metals o Suite 3—Chromium o Suite 4—Pesticides
The analytical parameters, methods, and where applicable, the detection limits for each analytical suite are shown in Table 2.
U.S. Environmental Protection Agency, 1979, Methods for Chemical Analysis of Water and Wastes, EPA-600/4-79-020, Revised March 1983.
, 1982, Test Methods for Evaluating Solid Wastes, Physical/Chemical Methods, SW-846, revised April, 1984.
'Mercury's detection limit is contingent on the volume of digestion solution used. 10 ml of digestion solution to 0.2 g of soil results in a 0.05 mg/kg detection limit, but if 5 ml of digestion solution is added to 0.2 g of soil, the detection limit is 0.11 mg/kg. A smaller volume of , solution may be used to limit the frothing of the solute to avoid the potential volatilization of mercury.
RD/R91/040
SELECTION OF SAMPLING LOCATIONS
VOC SAMPLING LOCATIONS
Nineteen soil borings were sampled at 5-foot intervals to a depth of 6 5 feet or until the groundwater table was encountered. Fifteen of these locations corresponded to previous soil gas sampling locations where the concentration of VOC's, primarily TCE, was equal to or greater than 10 yg/l. This threshold concentration level was believed to be indicative of contaminant source areas. The remaining four borings were completed around the large hangar apron area and at the former location of the Navy's aircraft washracks (Figure 3). These additional locations were selected to determine if the former washrack area is a source of VOC and chromium contamination, since the samples collected from these borings were analyzed for both VOC's and total chromium.
Additional soils data to assess the contamination by VOC's were needed to determine if the PGA soils are a continuing source of groundwater contamination or if they are contaminated to the extent that they exceed the ADEQ soil action limits.
PESTICIDE SAMPLING LOCATIONS
Soil samples were collected from three different areas at the airport to characterize the degree of soil contamination from the pesticides 4-DDE' and 4-DDT'. These samples were collected because background samples from the source verification investigation contained these pesticides at concentrations near the ADEQ action limits.
Based on personal communication with ADEQ representatives, the western portion of the Salt River Valley historically received frequent applications of DDE and DDT to suppress pink bole worm in cotton, and the ADEQ has found that where sediments have been dredged from irrigation ditches, the sediments have contained elevated levels of pesticides. In addition to the potential contamination from dredged sediments, it was determined that areas used by crop dusting aircraft should also be sampled.
The three areas sampled for pesticide contamination were as follows:
o The dredged sediments along the course of the airport ditch (Figure 3)
o The area adjacent to the southeast side of the concrete apron of the large hangars (Figure 4)
RD/R91/040
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^ CHROMIUM SAMPLING LOCATIONS
C04093 DENOTES FIELD DUPLICATE SAMPLES
F I G U R E 4
SOIL SAMPLING L O C A T I O N S NEAR THE AIRPORT HANGARS
t AND FORMER PAINT TENT
PHOENIX G O O D Y E A R AIRPORT
I S O I L S I N V E S T I G A T I O N
W 6 3 6 0 0 . F T O C T O B E R 1 9 8 7
! •
o The extreme southwestern end of the airport property where the sediments dredged from the airport drain ditch have been disposed of by airport personnel (Figure 5)
These locations are each approximately 2,500 feet away from the location of the sample point of the background sample that contained 4-DDE' and 4-DDT', but based on the past historical use of the airport, these locations appeared to be the most logical areas to sample.
At each location where dredged sediments were sampled, both along the airport ditch and at the southwestern airport fill area, the cuttings collected from augering through the sediments were composited from a depth of 0 to 60 inches or from the top of the sediment pile to the original ground surface, whichever was shallower. These sediments were suspected of containing elevated levels of pesticides since they are the result of runoff and subsequent erosion of agricultural lands that have historically received pesticide applications.
Airport Ditch
Composite soil samples were collected at four locations from the sediments dredged from the airport drain ditch that lies to the west of the runway (Figure 3) with a hand auger to a depth of about 5 feet at approximately 500-foot intervals along the course of the ditch.
Hangar Apron Area
The area southeast of the hangar apron area is the only area identified by airport personnel which has been used by crop dusting aircraft, and this area potentially receives surface runoff from the apron area. Near the hangar apron area, 14 sample locations were organized in a 200-foot grid pattern (Figure 4). This grid initiated at the southeastern edge of the apron and extended downslope toward the southeast. Soil samples were collected from backhoe test pits excavated to a depth of about 5 feet at the following depths such that the vertical distribution of the potential pesticide contamination could be evaluated: 0 to 4 inches, 4 to 8 inches, 8 to 15 inches, and 15 to 30 inches.
Southwest Airport Fill Area
Composite soil samples were collected from four locations with a hand auger to a depth of about 5 feet at the locations shown in Figure 5. This area is the airport's fill disposal area where sediments derived from the airport drain ditch have been periodically disposed of by airport personnel.
RD/R91/040
DATE OF PHOTOGRAPHY APRIL 1987
Nl I ' s l O O '
LEGEND
SAMPLING LOCATION
(05103 DENOTES FIELD DUPLICATE SAMPLES
F I G U R E 5
PESTICIDE SAMPLING LOCATIONS OF SEDIMENTS DERIVED FROM
I THE AIRPORT DRAINAGE DITCH
PHOENIX-GOODYEAR AIRPORT
SOILS INVESTIGATION
W63600.FT OCTOBER 1987
CHROMIUM SAMPLING LOCATIONS
Soil samples were collected from four different areas on both the former GAC facility and the airport property. The areas sampled were the two former sludge drying beds at GAC, the former sewage treatment facility at the airport, the former location of the airport drain ditch initiating from the outfall of GAC's Drain 001, and the location of the Navy's former paint tent. (See Figures 4, 6, 7, and 8.)
Former GAC Sludge Drying Beds
During the source verification investigation, the two GAC former sludge drying beds were sampled. The analyses for total chromium detected chromium at twice the ADEQ's action limit in the surface 0 to 1.5 feet at the smaller eastern bed, and a surface soil sample near the southwestern corner of the larger western bed contained chromium at a concentration of 1,400 mg/kg. Since the sampling conducted during the source verification did not attempt to define the horizontal extent or vertical distribution of chromium contamination, additional soil sampling was necessary to facilitate the determination of the volume of soil potentially requiring remedial action.
Ninety-six soil samples were collected from the two former sludge drying beds: 48 samples from the larger western bed, and 48 samples from the smaller eastern bed (Figure 6). The samples were collected from backhoe test pits excavated to a depth of about 10 feet. Samples were collected from the following depths at each location: 0 to 4 inches, 4 to 8 inches, 8 to 15 inches, 15 to 30 inches, 30 to 45 inches, 45 to 60 inches, 60 to 90 inches, and 90 to 120 inches.
In addition to the samples collected for total chromium, samples were collected for the metals analytical suite at Locations 0601/0602, 0603, 0604, and 0608 from sludge bed No. 1, and at Locations 0701/0702, 0703, and 0705 from sludge bed No. 2. These additional samples were collected at 0 to 4 inches, 4 to 8 inches, and 8 to 15 inches. They were primarily collected to attain additional metals data for the study area's Public Health Endangerment Assessment, but they were also collected to assess the potential for surface soil contamination by other metals.
Former Airport Sewage Treatment Facility
This facility was in operation from 1951 until sometime after 1982. In 1952 the facility was upgraded to a secondary treatment facility, and industrial wastewater from the airport drain ditch was diverted to the facility for treatment. Since the Navy reportedly never used the air flotation system in its treatment of wastewater, essentially
SOIL SAMPLING LOCATIONS AT THE FORMER GAC SLUDGE DRYING BEDS
' PHOENIX-GOODYEAR AIRPORT I
! . SOILS INVESTIGATION
W63600.FT OCTOBER 1987
DATE OF PHOTO
- ^ SAMPLING LOCATION
C10023 DENOTES FIELD DUPLICATE SAMPLES
F IGURE 7 SOIL BORING LOCATIONS
AT THE FORMER P.G.A. SEWAGE TREATMENT FACILITY
PHOENIX-GOODYEAR AIRPORT SOILS INVESTIGATION
W63600 .FT OCTOBER 1987
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untreated industrial wastewater was discharged from the bottom of the flotation tank to the airport ditch through an unlined channel (Ecology and Environment, 1986). The chemical composition of the industrial wastewater is unknown, but in 1951 samples of this wastewater were collected, and based on their physical appearance, it was suspected that they contained chromates (Ecology and Environment, 1986). The facility is no longer present, but historical aerial photography was enlarged to a 1-inch to 500-foot scale such that the former facility could be located on current 1987 photography. The location of the treatment ponds and the unlined ditch which channeled wastewater into the airport ditch was determined from this historical photography.
Four soil borings were completed at the former location of the airport's sewage treatment facility. Two soil borings were placed at the location of the former filtration ponds, and the other two borings were placed along the course of the unlined channel which emptied into the airport drain ditch (Figure 7). The borings were completed before the groundwater table was encountered. Soil samples were collected at 5-foot intervals in brass sleeves with a California modified split-spoon sampler.
Former Airport Drain Ditch Near the Outfall of GAC Drain 001
Historically this drain ditch received industrial waste from the GAC facility under a National Pollutant Discharge Elimination System (NPDES) permit. During the source verification investigation, the sewerlines at GAC which fed this ditch were sampled, and TCE and chromium were detected at 80,000 ppm and 1,587 ppm, respectively. Also during this investigation, soil borings were completed near the 001 outfall point and at other locations spaced at very large intervals along the course of the ditch, but none of the soil borings were situated directly in the course of the former unlined ditch.
3 Aerial photography flown February 20, 1949 , clearly identifies the original location of the unlined airport ditch. This photography was enlarged to a 1-inch to 500-foot scale and overlaid on 1987 photography to identify the historical location of the unlined drain ditch.
Four soil borings were completed along the historical course of the airport ditch. The first boring was located at the initial outfall point of GAC Drain 001, and the remaining locations were situated along the former ditch's route at
3 U.S. EPA. Aerial Photographic Analysis of a Hazardous Waste Study Area. Goodyear, Arizona. June 1983.
RD/R91/040
approximately 250-foot intervals (Figure 8). Soil samples were collected in brass sleeves with a California modified split-spoon sampler at 5-foot intervals to a depth of 65 feet or until the groundwater table was encountered.
Former Paint Tent
Three soil borings were completed at the vicinity of the former paint tent. Reportedly, chromic acid was used during the preparation of aircraft during painting operations. The location of the paint tent is still easily found, so borings were completed upslope, near the middle, and downslope from the pad where painting operations took place (Figure 4). Samples were collected at 5-foot intervals in brass sleeves with a California modified split-spoon sampler to an approximate depth of 40 feet or until the capillary fringe above the groundwater table was encountered.
ARCHIVE SAMPLES
Archive samples were collected at each sampling location and sampling depth for additional physical and chemical soil property tests. These analyses are being conducted on soil samples which contain contaminants near the ADEQ soil action limits. The results from these tests will be used in confirming the site stratigraphy, and in evaluating soil properties that may influence the adsorption or mobility of the contaminants being investigated. The following is a list of the physical and chemical soil property tests being conducted:
o Sodium acetate cation exchange capacity o Total organic carbon o Moisture content o Particle-size analysis o Extractable cations o Soil pH o Water soluble chromium elution tests
The archive samples for a given sample location will be analyzed if any of the previously analyzed samples collected from a given location are contaminated to the extent that they approach or exceed the ADEQ action limits. Table 3 presents the criteria for analyzing archive samples.
The intent of establishing these threshold concentration values was to allow for the characterization of the vadose zone. The concentration value for VOC's was established to provide data at all of the locations where suspected VOC contamination would be detected. The chromium concentration value was established to address the potential solubility of the suspected chromium contamination over a range of concentration values below the ADEQ's limit for total chromium.
Percent moisture tests were conducted on all samples at the time of analysis for contaminants.
The aluminum and pesticide concentration values were established very close to their ADEQ action limits, such that the locations where these potential soil contaminants would be increasing towards or decreasing from the ADEQ limits could be investigated.
BACKGROUND SOIL SAMPLING LOCATIONS
This portion of the overall sampling effort was completed to determine the background contaminant concentrations for the suspected contaminants at PGA. The sampling of background locations was also completed to provide data for the public health endangerment assessment. Prior to this sampling effort there were insufficient data to determine if there are potential health risks associated with exposure to the site's soils.
Background soil samples were collected from eight offsite locations near the PGA site as shown in Figure 9. The locations were selected on the basis of being representative of the principal soil taxa that occur at the PGA site, and the three major land uses adjacent to the site. Soil samples were collected for metals, pesticides, and soil properties in accordance with the methods described in this memorandum from the locations where the Laveen, Gilman, and Glenbar soils occur under agricultural, residential, and industrial land use. This matrix scheme was achieved for the respective soils and the various land uses with the exception of the Glenbar soil in a residential setting. In this instance, a site which met this criterion could not be located. To alleviate this problem, a second location with the Laveen soil under residential land use was selected for sampling.
RD/R91/040 11
SAMPLING METHODS
Due to the different sampling techniques used during this field sampling effort, each sampling methodology used will be discussed according to the sampling technique or type of contaminant being investigated.
BACKHOE TEST PITS FOR PESTICIDES AND CHROMIUM
Soil samples were collected from backhoe test pits at background locations, near the airport hangars, and at the locations of the former GAC sludge drying beds. To facilitate viewing the soil profiles that were excavated, the pits were dug such that the length of the pit was parallel to the angle of the sun. While digging the pits, the backhoe contractor attempted to stockpile the excavated soil in piles that correspond to 2-foot intervals to facilitate replacement of the soil to its original location. Where soil samples were collected for pesticides, the pits were dug to a depth of about 5 feet; when samples were collected for chromium, the pits were excavated to a depth of about 10 feet (120 inches). Prior to any member of the sampling team entering a test pit, the backhoe subcontractor would place 7-foot aluminum hydraulic shoring devices in the pit at 4-foot centers to brace the sides of the pit such that it would be safe for members of the sampling team to enter the trench. At 10-foot test pit sites, the 7-foot shoring devices were placed 2 feet from the bottom of the trench, and the remaining 1 foot of soil was sloped back to the top of the shoring device.
After the test pit was adequately braced, the field soil scientist and one other team member entered the pit and collected samples in the following manner:
1. The soil scientist completed a soil profile description of the pit using National Cooperative Soil Survey (NCSS) abbreviations and terminology. Descriptions were completed at various sampling locations as outlined in the PGA Soil Sampling Plan (CH2M HILL, 1987).
2. The soil scientist then used a plastic-coated cloth tape to measure the required sampling depths along the side of the trench that was most representative of the soil profile. The sampling intervals were marked with pin flags that had been labeled with the appropriate depth measurement. The soil scientist then smoothed off the face of the pit with a clean trowel from the soil surface to the bottom of the pit and began sampling the pit at the lowest sampling depth and progressing upward.
RD/R91/040 12
3. To avoid cross contamination of samples, a small cavity was dug into the wall of the pit at the lower limit of the particular sampling depth sufficient in size to place the sample jar into. Then the soil scientist used another clean trowel to scrape a soil sample into the jar from above, taking care to avoid roots and excessive amounts of gravels. This step was repeated for every sample collected from each particular sampling depth.
4. After the soil scientist collected the samples for a given depth, the sample was given to the other team member to complete filling out the sample container label, decontaminate the sample container, package the samples, complete the necessary sample documentation, and place the samples in an ice cooler with frozen "Blue-Ice" packages.
5. When the sampling was completed for a given location, the backhoe operator removed the shoring devices and backfilled the pit according to the segregated piles of soil that were excavated during the digging of the pit.
HAND-AUGERED SAMPLES FOR PESTICIDES
Composite soil samples to be analyzed for pesticides were collected from the dredge piles adjacent to the airport drain ditch west of the runway, and at the extreme southwestern end of the airport property where airport personnel have disposed of sediments dredged from the airport ditch and other fill material. Samples were collected at approximately 500-foot intervals along the ditch, and approximately 250 feet apart at the fill disposal area. When the composite samples were collected, the following procedure was used:
1. The sampler selected a representative location directly adjacent to the ditch or near the edge of the fill disposal area for sampling. Once a representative location had been selected, the sampler used a decontaminated hand auger to auger a hole down through the sediments until the original ground surface was encountered or until the entire length of hand auger had been used. While augering, the sampler saved all of the cuttings on a clean plastic sheet.
2. After the sampler completed the augering, the cuttings were run through a sample splitter.
RD/R91/040 13
3. When the sample had been split, one portion of the split sample was placed in an 8-ounce sample jar for pesticide analysis and appropriately labeled. Then the sample was split again to attain a 16-ounce archive sample for physical and chemical soil property tests.
4. The remaining soil was placed back in the residual auger hole, and the plastic sheet was disposed of according to the procedures for disposal of generated wastes described in the PGA Soil Sampling Plan (CH2M HILL, 1987) .
SOIL BOREHOLE DRILLING
Soil borings were completed at the former location of the airport sewage treatment facility, the former location of the airport drain ditch near the outfall of Drain 001, near the former paint tent, near the hangar apron and former wash-racks, and at the VOC boring locations where soil gas measurements appeared to be indicative of potential contaminant source areas. A double-wall percussion air hammer was used to advance the boreholes and to obtain samples at 5-foot intervals with a 24-inch California modified split-spoon sampler. This method was selected because the technology is well established for drilling in soils with a high content of coarse fragments, the method is quite rapid, and because a hollow stem auger rig could not perform to the required specifications. When collecting samples from borings, the following procedure was used:
1. After the drill pipe had been decontaminated, the drill pipe was advanced to the depth at which a sample was to be collected. During this period in between sampling events, the materials encountered during drilling were recorded on a soil boring log.
2. A decontaminated California modified split-spoon sampler equipped with four 6-inch brass sleeves was connected to the appropriate length drill rod and lowered into the borehole through the orifice of the center pipe.
3. A falling hammer was connected to the drill rod, and driven into the undisturbed soil for a depth of 24 inches. The number of blow counts required to drive the sampler for each 6-inch interval was recorded on the soil boring log.
RD/R91/040 14
4. After the falling hammer, drill rod, and the split-spoon sampler had been removed from within the inner orifice of the drill pipe, the hammer was lowered back onto the drill pipe and drilling continued to the next sampling depth.
Chromium Borings
When collecting soil samples for chromium analysis, the following procedure was used:
1. After the sampler had been driven for a depth of 24 inches at a particular 5-foot sampling depth and removed from the borehole, the sampler was disassembled to expose the brass sleeves.
2. The first two 6-inch sleeves were not shipped as capped sleeves, but had their contents extracted with a decontaminated stainless steel spatula, and placed in an appropriately labeled 8-ounce sample jar. This jar contained the soil for the chromium analyses.
3. The excess soil remaining in the second sleeve with the majority of the contents of the third sleeve, was placed in a 16-ounce jar and appropriately labeled as an archive sample for physical and chemical soil property tests.
4. That portion of the third sleeve which was not placed in the 16-ounce jar was used for completing the boring log.
5. The contents of the fourth 6-inch sleeve was disposed of with the cuttings that were generated during the drilling of the borehole.
VOC Borings
In addition to the soil samples collected from soil borings for chromium analyses, soil samples for VOC's were also collected from soil borings. During this sampling effort, a conscious effort was made to avoid the loss of VOC's during sample collection. The method that was used proceeded in such a manner that the soil samples were exposed to the ambient air for only a very brief time period from the point of sample collection to the completion of the sample analysis. The collection of soil samples for VOC analysis proceeded in the following manner:
1. Since a methanol extraction was completed in the field for samples collected for VOC analysis, the
RD/R91/040 15
125-milliliter headspace jars used for sample containers were filled with 25 milliliters of methyl alcohol prior to initiating the day's fieldwork. Prior to sampling, the headspace jars that were expected to be used during that day's work were labeled according to their anticipated sample identification number, date, and initials of the sample team members.
2. Prior to driving the decontaminated California modified split-spoon samplers into the soil at each specified sampling depths, the samplers had been stored in a cooler filled with "Blue-Ice" in sealable plastic bags. This was done to negate the effects of friction generating heat during the driving of the sampler. The drilling subcontractor supplied two samplers that were recycled during the drilling operation. This allowed the samplers to remain in a cold environment for approximately 20 minutes in between decontamination and use.
3. After the sampler had been driven to collect a sample for one of the specified depths, the sampling team moved rapidly when disassembling the sampler to expose the brass sleeves and collect soil samples. The first 6-inch sleeve contained the soil that was extracted from the sleeve with a stainless steel spatula into the tared headspace jar that was prepared with methyl alcohol.
4. Approximately 10 grams of field-moist soil was placed into each prepared headspace jar that had been appropriately labeled for VOC analysis and tared on a portable electronic balance. After the soil was placed in the jar, the lid was replaced, and the weight of the field-moist soil was recorded on the appropriate line of the chain-of-custody form and in the field notebook.
5. After the sample had been weighed into the jar, the lid tightened down, and the label completed with the necessary information, the labels were covered with clear plastic tape; the lids were sealed with black electrical tape; and the jars were custody-sealed, prepared for shipment, and placed in a cooler containing frozen "Blue-Ice" packages in sealable plastic bags.
6. That portion of the first sleeve which was not used in the collection of samples for VOC analysis was removed from the sleeve along with the contents of the second and the majority of the third
RD/R91/040 16
sleeve's contents into a 16-ounce jar that had been labeled as an archive sample for future physical and chemical soil property tests.
7. Approximately a 2-inch slice from the third sleeve's core sample was used in completing the borehole log.
8. The contents of the fourth 6-inch sleeve was disposed of with the cuttings generated during the drilling of the borehole.
DEVIATIONS FROM THE SOIL SAMPLING PLAN
During the course of the field investigation and the completion of the sample analyses, a number of decisions were made to expedite the completion of the work associated with this sampling effort and to minimize the cost of this investigation whenever possible. Any of the deviations from the PGA Soil Sampling Plan (CH2M HILL, 1987) that occurred during this investigation were evaluated prior to their initiation to ensure that they would not influence the quality of the work completed at the site or in the laboratory. For ease of discussion, deviations from the PGA Sampling Plan will be discussed according to field or laboratory adjustments.
FIELD EFFORT CHANGES
Field decisions that were made during the course of the sampling phase of this investigation consisted of changes in drilling methods, deleting or moving sampling locations, and the disposal of cuttings generated during the drilling of borings.
Drilling Method
The soil sampling plan described the use of a continuous flight hollow-stem auger as the type of drilling equipment to be used for the investigation, but the drilling subcontractor presented the use of a double-wall percussion air hammer as a more effective means of drilling considering the nature of the site's coarse-grained stratigraphy. The air hammer was initially used to collect samples for chromium analysis from the sampling locations at the former sewage treatment facility and at the sampling locations near the former paint tent. At these sampling locations, the air hammer proved to be a more effective and rapid means of collecting samples. This method also allowed for a more accurate description of the vadose zone stratigraphy.
RD/R91/040 17
I
I I I i i t I
i I I I I I I I I
When the sampling for VOC's was initiated, a Mobile P-80 8-inch hollow-stem auger rig was used, but auger refusal occurred at 27 feet and 30 feet at Boring Locations 0901 and 0910, respectively. Based upon the poor performance of the hollow-stem auger, a decision had to be made that would allow the collection of the samples specified in the Sampling Plan.
Because there was concern over the air harmner potentially volatilizing the VOC's from the soil, both rigs were placed side by side at Location 0901, and duplicate samples were collected to a depth of 30 feet (the point of auger refusal) to see if there would be a difference in the results obtained from the analyses of the samples obtained from either drilling method. This location was selected because it had a corresponding soil gas concentration of 9,517 vig/l TCE, but after the results from the analyses of these duplicate samples were obtained, none of the soil samples collected with either drilling method contained TCE or any other VOC in excess of the 0.1 mg/kg detection limit.
After considerable discussions over the strengths and weaknesses of either drilling method, a decision was made to use the double-wall percussion hammer with a 24-inch California modified split-spoon sampler driven ahead of the drill head to avoid the possibility of volatilizing the potential soil contaminants.
Sampling Locations
Certain sampling locations that were initially intended to be sampled were deleted from the sampling effort as a result of denied access, being deemed unnecessary, or because of circumstances in the field.
One background sampling location, 0130, was not sampled because the landowners denied access. As a result, the overall number of background samples was reduced, making it unnecessary to collect field duplicates at Location 0120 because duplicate samples would already comprise 25 percent of the background samples collected.
The Plan had specified that background soil samples would be collected for VOC analyses and for chromium analyses at depth, but after reviewing preliminary data from samples collected onsite, it was determined that the collection of these samples would be unnecessary. This determination was based on the fact that VOC's had not been detected at suspected contaminant source areas, and that the chromium data from samples collected at depth from suspected source areas did not indicate elevated concentrations of chromium.
RD/R91/040 18
! •
The only onsite location that was not sampled was Location 0605. This location was not sampled because an active sewerline was damaged during the excavation of this backhoe test pit, and structures encountered during the excavation of this pit adequately indicated that this location was situated outside of the former sludge bed.
Due to the physical size of the drilling equipment used, a number of sampling locations were adjusted to accommodate the drill rig. The only locations where the relocation of a sampling site was particularly significant were at Locations 0917 and 0804. The location of 0917's corresponding soil gas probe placement was very close to the primary taxiway for much of the airport's aircraft traffic, so the boring location had to be moved. This move resulted in this boring being placed where the earlier soil gas sampling survey had detected TCE at 2.75 yg/l. Location 0804 was moved just to the west of the former airport drain ditch because the split-spoon sampler hit an obstruction at 5 feet that would not allow a sample to be collected, and the airport operations manager requested that the drill rig be moved to the location shown on Figure 8 after the presence of the obstruction was brought to his attention.
Storage of Drill Cuttings
The soil sampling plan had specified that the cuttings generated during drilling operations would be stored in drums prior to disposal according to each boring location, but based on the lack of available space for drum storage, 10-yard roll-off boxes were used. This was found to be a more efficient means of storage. Prior to disposal, composite samples of the cuttings will be collected to assess the potential degree of remaining contamination. If the results of these analyses indicate that the contaminants have volatilized, the cuttings will be disposed of onsite; but if the cuttings remain to be contaminated to the degree that they cannot be disposed of onsite, an appropriate waste disposal alternative will be selected.
LABORATORY ANALYTICAL PROCEDURE CHANGES
During the course of the laboratory's involvement in this investigation, there were a number of changes in terms of analytical requests that the laboratory was instructed to make to reduce the analytical time and cost for particular portions of the investigation. The changes that deviated from the sampling plan were focused on the staging of the analyses conducted on the soil samples collected for pesticides near the hangar apron area; in reducing the number of samples requiring the water soluble chromium elution tests; and adding the EP Toxicity test for chromium to the group of analytical methods comprising the chromium analytical suite.
RD/R91/040 19
Pesticide Analyses
The analysis of the soil samples collected from the area near the hangar apron was staged in an effort to reduce analytical time and cost. Initially, the staging of the analyses was to proceed with the results from the complete analysis of the first two sampling depths being reviewed to determine whether the remaining two deeper sampling depths warranted being analyzed. But, due to the number of samples to be analyzed and the concern of exceeding the analytical holding times of the samples, all of the samples collected were extracted to meet the analytical holding times and the first two sampling depths were analyzed. After these data were reviewed, it was determined that the analysis of the sampling depths was unnecessary, since there was a marked decrease in pesticide concentrations at the 4- to 8-inch sampling depth, and of the three locations where pesticides were detected none approached the ADEQ soil action limits for 4-DDE' or 4-DDT'.
Soluble Chromium Elution Tests
The sampling plan specified that all of the samples collected from a given location would be analyzed for the chromium elution test if any sample contained total chromium in excess of 500 mg/kg. The only samples analyzed from the field investigation that met the total chromium criterion were collected from the former GAC sludge drying beds. All of the samples associated with a sample that exceeded the total chromium criterion would have been analyzed, but the review of the preliminary data revealed an abrupt decrease in chromium concentration with depth rather than gradual attenuation of concentration with depth. It was decided to analyze only the samples that exceeded 500 mg/kg of total chromium for the chromium elution test.
Chromium EP Toxicity Test
The chromium EP Toxicity test was added to the list of analytical parameters after it was learned from the ADEQ that this type of test is required to determine if a remedial action is necessary. These tests are currently being completed on soil samples that contain total chromium in excess of 500 mg/kg. The tests will be discussed in the final soils investigation technical memorandum.
RESULTS
The results obtained from the analysis of the background soil samples, and the onsite soil samples analyzed for VOC's, pesticides, and chromium will be discussed according to the area sampled and the type of contaminant being investigated.
RD/R91/040 20
BACKGROUND SITES
Background soil samples were collected from various locations within the PGA Study Area where the Laveen, Glenbar, and Gilman soils were found at areas zoned for agricultural, residential, and industrial use. This matrix was developed to assess if the soils at the airport or GAC were significantly contaminated to a greater degree than the genetically similar offsite soils, and if the site's soils were contaminated to a significantly greater degree than other land use areas (Figure 9).
The results obtained from the analysis of samples collected for chromium, metals, and pesticides are found in Tables 4 through 6, respectively.
Pesticides
As was expected, the results of the pesticides analyses from agricultural sites contain 4-DDE' and 4-DDT' at greater concentrations than the other background sampling locations. At Location 0110, 4-DDE' was detected at 1.13 mg/kg and 1.47 mg/kg at depths of 4 to 8 inches and 8 to 15 inches, respectively. Both concentration values are in excess of the ADEQ action limits for 4-DDE'. Of the two agricultural sites sampled. Locations 0110 and 0120, there is a definite greater proportion of 4-DDE' to 4-DDT'. It appears that a degradation process of some kind has possibly brought about the transformation of 4-DDT' to form 4-DDE'.
Of the remaining background sites sampled for pesticides. Location 0320, a zoned residential site, and Location 0210, a zoned industrial site, have somewhat anomalous pesticide concentrations. Location 0210's pesticide concentrations can possibly be attributed to the fact that this location is adjacent to an agricultural area, but unlike the other agricultural sites, the concentration of 4-DDT' is greater than 4-DDE'. Location 0320 has the highest concentration of pesticides from any of the zoned residential sites, and the concentration of 4-DDE' does not decline with depth like the majority of the other background sampling locations.
Chromium and Metals
Of the background locations where samples were collected for total chromium and the metals analytical suite, all of the chromium concentrations and other metals concentrations are consistent for all of the sampling locations.
RD/R91/040 21
Table 4 PESTICIDE CONCENTRATIONS FROM BACKGROUND SAMPLING LOCATIONS
(mg/kg)
to
Sampling
Depth
(inches)
0-4 4-8 8-15 15-30
Sampling
Depth
(inches)
0-4 4-8 8-15 15-30
Sampling
Depth
(inches)
0-4 4-8 8-15
15-30
DDE
0.93 1.13 1.47 0.05
DDE
0.18 0.02 0.02
ND
DDE
0.8 ND 0.02
ND
0110
0220
0311
DDT
0.28 0.50 0.99
ND
DDT
0.01 ND ND ND
DDT
0.01 ND 0.01 ND
DDE
0.40 0.03 0.35 0.47
DDE
0.02 0.02 0.02
ND
DDE
0.42 0.43 0.61 0.87
0120
0230
0320
Test Pit
DDT
0.02 0.01 0.01 0.02
Test Pit
DDT
ND ND ND ND
Test Pit
DDT
0.05 0.21 0.13 0.09
Location
DDE
0.24 0.18 0.12 0.01
Location
DDE
0.01 ND ND ND
Location
DDE
0210
0310
DDT
0.32 0.40 0.26 0.03
DDT
ND ND ND ND
DDT
DDE
0.16 0.24 0.18 0.01
DDE
ND ND ND ND
DDE
0241
0341
a
DDT
0.07 0.29 0.32
ND
b
DDT
ND ND ND ND
DDT
Fielci duplicates of Test Pit Location 0210.
Field duplicates of Test Pit Location 0310.
Note: All concentrations reported on an oven dry basis.
ND = Not detected at a concentration greater than 0.01 mg/kg.
RD/R15/015-1
Table 5 CHROMIUM CONCENTRATIONS FROM BACKGROUND SAMPLING LOCATIONS
(mg/kg)
Sampling Depth
(inches)
0-4 4-8 8-15
15-30 30-45 45-60 60-90 90-120
Sampling Depth
(inches)
0-4
4-8
8-15
15-30
30-45
45-60
60-90
90-120
0110
15 16 16 14 12 14 16 12
0311
24
20
21
16
19
19
18
19
0120
34 36 34 24 25 22 14 13
0320
21
18
21
20
18
21
18
11
0210
16 14 17 17 13 18 22 30
Test Pit
0241^
14 15 14 14 15 15 21 22
Test Pit
Location
0220
16 16 16 15 16 18 15 13
Location
0230
28 19 29 22 22 23 21 16
0310
27 26 27 20 15 14 21 15
034l'=
27 21 18 16 18 15 16 15
Field duplicates of Test Pit Location 0210.
^Field duplicates of Test Pit Location 0310. Note: All concentrations reported on an oven dry basis.
RD/R15/016-1
Table 6 CONCENTRATIONS OF METALS FROM BACKGROUND SAMPLING LOCATIONS
(mg/kg)
K)
>̂
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Sampling Depth (inches)
0-4 4-8 8-15
15-30
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Al
8,822 8,401 8,056 8,236
Al
15,497 13,832 16,067 16,817
Al
9,381 7,963 13,147 9,748
Al
8,421 8,379 8,421 8,500
As
8.6 9.5 8.6 8.7
As
6.1 6.0 6.5 6.5
As
9.5 9.2 8.7 10.2
As
7.3 8.1 8.6 11.5
Ba
130 158 158 218
Ba
168 164 169 169
Ba
152 154 176 178
Ba
142 163 165 177
Test
Cd
0.4 0.3 0.6 0.5
Test
Cd
1.2 1.0 1.7 0.6
Test
Cd
0.3 0.4 0.2 0.3
Pit
Pit
Pit
Test Pit :
Cd
0,4 0.4 0.4 0.4
Location 0110
Cu
13 11 11 10
Hg
ND ND ND ND
Location 0120
Cu
24 23 25 23
Hg
ND ND ND ND
Location 0210
Cu
15 14 16 15
Location
Cu
15 14 14 14
Hg
ND ND ND ND
0241^
Hg
ND ND ND ND
Mn
205 180 169 160
Mn
419 348 371 463
Mn
314 287 290 283
Mn
263 255 289 250
Ni
12 12 12 10
Ni
19 17 20 20
Ni
15 14 13 15
Ni
14 13 12 14
Pb
9.5 9.3 8.0 5.7
Pb
11.5 8.7 11.2 10.4
Pb
8.2 6.6 6.8 5.5
Pb
9.1 7.3 7.3 7.1
Zn
32 30 33 25
Zn
63 60 81 54
Zn
37 34 36 34
Zn
35 33 33 31
RD/R15/018-1
Table 6 (continued)
N>
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Al
9,375 10,192 11,315 9,420
Al
8,558 9,130 15,328 12,685
Al
16,083 18,311 19,268 12,513
Al
15,470 11,790 12,283 10,063
As
10.1 9.9 9.8 8.1
As
16.1 12.1 9.4 9.6
As
8.5 13.2 12.9 7.5
As
8.7 13.1 14.1 8.6
Ba
151 172 173 163
Ba
151 121 156 116
Ba
142 164 172 147
Ba
155 153 152 147
Test
Cd
0.4 ND 0.4 0.4
Test
Cd
0.3 0.2 0.4 0.4
Test
Cd
0.4 0,5 0.3 0.2
Pit Location 0220
Cu
20 19 20 19
ND ND ND ND
Pit Location 0230 " •
Cu
18 18 27 23
Hg
ND ND ND ND
Pit Location 0310
Cu
30 36 33 20
Test Pit Location
Cd
0.3 0.3 0.4 0.3
Cu
28 29 29 20
Hg
ND ND ND ND
0341^
Hg
0.25 0.13 0.30 0.36
Mn
383 454 428 438
Mn
323 313 626 507
Mn
449 592 527 379
Mn
464 524 435 389
Ni
19 19 20 18
Ni
18 18 26 23
Ni
32 36 36 25
Ni
30 31 32 24
Pb
11.1 6.6 6.9 6.2
Pb
9.5 6.9 9.6 8.9
Pb
24.1 15.4 10.8 8.6
Pb
29.8 19.7 14.1 11.6
Zn
43 40 42 41
Zn
39 35 62 51
Zn
72 61 54 41
Zn
66 52 45 37
RD/R15/018-2
Table 6 (continued)
M (T\
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Sampling Depth (inches)
0-4 4-8 8-15 15-30
Al
14,442 14,485 14,454 10,086
Al
13,679 11,452 11,423 11,895
As
8.6 10.1 9.9 7.8
As
10.4 9.2 8.4 8.4
Ba
142 150 171 194
Ba
197 174 166 158
Test
Cd
0.3 0.5 0.5 0.5
Test
Cd
0.6 0.6 0.2 0.2
Pit Locat
Cu
24 25 25 19
ion 0311
Hg
ND ND ND ND
Pit Location 0320
Cu
27 20 24 24
Hg
ND ND 0.12
ND
Mn
416 472 471 399
Mn
487 368 467 516
Ni
25 27 29 23
Ni
27 25 28 27
Pb
15.3 10.7 10.7 8.2
Pb
17.6 9.0 9.8
11.6
Zn
59 49 50 39
Zn
54 47 51 52
Field duplicates of Test Pit Location 0210.
Field duplicates of Test Pit Location 0310.
Note: All concentrations reported on an oven dry basis.
ND = Not detected at a concentration greater than those found in Table 2.
RD/R15/018
RD/R15/018-3
The background aluminum concentrations are all greater than the ADEQ limits, but this action limit is prefaced by being subject to the determination of natural soil levels. When compared to onsite aluminum data, these data should reveal that the site's aluminum levels are not substantially greater than naturally occurring offsite conditions.
VOC BORINGS
Soil samples were collected for VOC analyses from borings completed at the locations where the previous soil gas survey detected TCE at a concentration equal to or greater than 10 yg/l, adjacent to the hangar apron and former aircraft washracks, and along the course of the former airport drain ditch near the outfall of GAC Drain 001 (Figures 3 and 8).
With the exception of methylene chloride, TCE was the only compound of all the VOC's being investigated that was consistently quantified above the 0.1 mg/kg detection limit. Methylene chloride was detected in nearly all of the samples and blanks analyzed, and its presence has been attributed to instrument contamination.
The six boring locations where TCE was quantified above the ADEQ suggested soil action limit of 260 yg/l to 320 yg/l are listed in Table 4. The highest concentrations of TCE detected were 2,270 yg/l at Boring 0902 at a depth of 30.5 to 31.5 feet, and 2,510 yg/l at Boring 0903 at a depth of 45.5 to 46.5 feet. With the exception of Boring 0909 and 0913, all of the borings with samples containing TCE above the ADEQ soil action limits are all close to existing sewerlines that service the former GAC facility.
In addition to the borings containing TCE in excess of the ADEQ soil action limits, TCE was detected in samples collected from Borings 0914 and 0803. At Boring Location 0803, located in the airport drain ditch near the outfall of Drain 001, TCE was detected at a concentration of 220 yg/l at a depth of 50.5 to 51.5 feet. At Location 0914, TCE was detected at 120 yg/l at 35.5 to 36.5 feet (Table 7). Boring 0913 was the only boring containing any of the other constituents from the VOC analytical suite. At this location, 1,1,1-TCA was detected at a concentration of 120 yg/l.
PESTICIDES
Soil samples for pesticide analyses were collected from backhoe test pits near the hangar apron area, as composite samples adjacent to the airport drain ditch to the west of the runway, and also as composites from the airport fill disposal area at the extreme southwestern end of the airport property (Figures 3, 4, and 5).
All data reported on an oven dry basis unless otherwise noted.
Data reported on a wet weight basis. Q
Last sampling depth of the boring. ND = Not detected at a concentration greater than 100 yg/kg. NS = No sample due to limited recovery.
As mentioned earlier, the analysis of the samples collected from backhoe test pits near the hangar apron area were analyzed in a stepwise fashion to reduce the overall analytical costs and to expedite the completion of the analytical work. After all of the samples had been extracted, the 0 to 4 inch and 4 to 8 inch samples were analyzed for 4-DDE' and 4-DDT' (Table 8). The review of these preliminary data resulted in none of the remaining samples being analyzed since the results of these analyses did not approach the ADEQ soil action limits of 1.0 mg/kg for 4-DDE' and 4-DDT'. This decision was also supported by the marked decrease in pesticide concentrations at the 4- to 8-inch sampling depth.
The composite samples collected from the sediments adjacent to the airport drain ditch and from the airport fill disposal area (Figures 3 and 5) contained both 4-DDT' and 4-DDE' at consistently higher concentrations than the samples collected near the hangar apron area. One sample, 0503, contained 4-DDE' at a concentration of 1.18 mg/kg.
RD/R91/040 28
Table 8 PESTICIDE CONCENTRATIONS FROM THE HANGAR APRON AREA
,a (mg/kg)
Sample Test Pit Location
NJ yo
Depth
(inches)
0 to 4
4 to 8
b 8 to 15
15 to 30̂ '̂ =
Sample
Depth
(inches)
0 to 4
4 to 8
8 to 15^
15 to 30̂ '̂ =
0401 0402 0403
DDE
0.01
ND
DDE
0.01
ND
ND
DDT DDE DDT DDE
0.02 ND 0.01 ND
ND ND ND ND
0410 0411
DDT DDE DDT
0.02 0.03 0.05
ND ND ND
ND
DDT
0.07
ND
0404
DDE
ND
ND
0412
DDE
0.03
ND
DDT
0.02
0.01
DDT
0.01
ND
Test
0405
DDE
ND
ND
ND
DDT
ND
ND
ND
Pit Location
0413
DDE
ND
ND
DDT
ND
ND
DDE
0.02
ND
0406
DDE
ND
ND
0414
DDT
0407
DDT DDE
ND 0.01
ND ND
DDT
0.02
ND
0415
DDE
0.02 0.17
ND 0.03
ND
DDT
0.33
0.22
ND
0408
DDE DDT
0.04 0.07
ND ND
0416
DDE DDT
0.02 0.01
ND 0.01
0409^
DDE DDT
0.04 0.07
ND ND
0417^
DDE DDT
ND ND
ND 0.02
ND ND
All (3ata reported on an oven dry basis. b Samples extracted but not analyzed.
c Any data appearing at this depth is a result of every tenth sample received by the laboratory being a
replicate spike sample.
d Field duplicate samples of Location 0408.
e F ie ld dup l i ca t e samples of Location 0416.
ND = Not detected a t a concentrat ion g rea t e r than 0.01 mg/kg.
R D / R 8 8 / 0 2 7 - 1
which is in excess of the ADEQ soil action limit (Table 9). At either location where composite samples were collected, the concentrations of 4- DDE' were consistently greater than the concentrations of 4-DDT'. This difference can possibly be attributed to the fact that 4-DDE' is a degradation product of 4-DDT', and that these sediments are the result of the runoff and subsequent erosion of agricultural lands that received applications of DDT many years ago to suppress infestations of pink bole worm in cotton. These data indicate that both pesticides are long-lived in soils, and that some degradation mechanism possibly has acted on 4-DDT' to result in comparatively greater concentrations of 4-DDE'.
Table 9 PESTICIDE CONCENTRATIONS IN SEDIMENTS DERIVED FROM THE AIRPORT DRAIN DITCH
Results are on a dry weight basis unless otherwise noted.
Results are on a wet weight basis.
Field duplicates of Location 0504.
Field duplicates of Location 0509.
METALS
Additional samples were collected from the former GAC sludge drying beds to attain additional metals data for the study
RD/R91/040 30
area's Preliminary Public Health Endangerment Assessment and to assess the potential of surface soil contamination by other metals.
Of the samples collected from Sludge Bed No. 1, the larger western bed (Figure 6), the surface 0- to 4-inch samples collected from Locations 0604 and 0606 contained cadmium in excess of the ADEQ soil action limit of 10 mg/kg (Table 10). Also, the sample collected from the 4- to 8-inch depth at Location 0602 contained cadmium at a concentration of 23.9 mg/kg. The only other sample with elevated concentrations of any of the other metals was derived from Location 0606, where copper was detected at a concentration of 303 mg/kg. This concentration just exceeds the ADEQ action limit for copper of 300 mg/kg.
Elevated cacJmium concentrations were also detected in the samples collected from Sludge Bed No. 2 at Locations 0701 and 0705. Cadmium in excess of ADEQ's action limit was detected in all of the samples from 0701 that were analyzed for metals, with the greatest concentration of 122 mg/kg occurring at a depth of 8 to 15 inches. At Location 0705, cadmium was detected at 15.3 mg/kg.
The remaining samples collected from Sludge Bed No. 2 that were analyzed for these additional metals did not contain elevated concentrations of the other metals investigated.
CHROMIUM
Soil samples were collected for chromium analyses at the following locations: near the hangar apron area and the former aircraft washracks, the former GAC sludge drying beds, at the former location of the airport's sewage treatment facility, and along the course of the airport drain ditch near the outfall of Drain 001 (Figures 3, 6, 7, and 8). Of the locations sampled for chromium analyses, one of the sludge drying beds detected chromium concentrations in excess of the ADEQ soil action limit of 1,500 mg/kg of total chromium.
Soil samples were collected from the former GAC sludge drying beds from backhoe test pits excavated to a depth about 10 feet, and samples were collected at the following depths: 0 to 4 inches, 4 to 8 inches, 8 to 15 inches, 15 to 30 inches, 30 to 45 inches, 45 to 60 inches, 60 to 90 inches, and 90 to 120 inches.
RD/R91/040 31
Table 10 METAL CONCENTRATIONS FROM THE GAC SLUDGE DRYING BEDS
(mgAg)
NJ
Sampling Depth (inches)
0-4 4-8 8-15
Sampling Depth (inches)
0-4 4-8 8-15
Sampling Depth (inches)
0-4 4-8 8-15
Sampling Depth (inches)
0-4 4-8 8-15
Al
10,467 7,121 9,586
Al
9,939 10,995 10,851
AI
10,243 10,082 10,093
Al
9,072 10,747 9,958
As
9.9 7.7 8.7
As
8.7 9.0 8.2
As
10.1 7.6 6.9
As
8.2 6.6 11.4
Ba
132 135 179
Ba
142 168 138
Ba
162 143 145
Ba
161 81 156
Test
Cd
6.5 23.9 3.0
Test
Cd
3.5 1.6 1.3
Test
Cd
20.3 2.2 1.4
Test
Cd
11.1 1,1 1.1
Pit
Pit
Pit
Pit
Locat
Cu
24 20 26
ion 0602
Hg
0.11 0.11
ND
Location 0603
Cu
19 18 17
Hg
ND ND ND
Location 0604
Cu
22 23 23
Hg
ND 0.11 0.11
Location 0606
Cu
303 19 18
Hg
0.11 0.11
ND
Mn
335 249 268
Mn
294 283 266
Mn
274 296 331
Mn
283 358 312
Ni
17 26 28
Ni
15 15 13
Ni
17 15 15
Ni
19 16 15
Pb
20.3 18.7 7.0
Pb
8.8 8.7 7.3
Pb
25.4 9.7 6.8
Pb
41.4 5.6 5.6
Zn
61 44 35
Zn
43 40 35
Zn
85 40 39
Zn
242 39 36
RD/R15/017-1
Table 10 (continued)
CJJ
OJ
Sampling Depth (inches)
0-4 4-8 8-15
Sampling Depth (inches)
0-4 4-8 8-15
sampling Depth (inches)
0-4 4-8 8-15
Sampling Depth (inches)
0-4 4-8 8-15
Al
10,303 9,240 8,635
Al
10,275 27,778 6,107
Al
16,410 10,681 12,940
Al
12,012 9,947 9,502
As
11.1 8.2 8.5
As
13.2 9.3 11.5
As
12.3 9.0 11.2
As
11.3 11.6 8.7
Ba
152 156 160
Ba
193 189 232
Ba
195 199 238
Ba
226 221 166
Test
Cd
4.8 1.4 1.4
Test
Cd
11.2 11.5 112
Test
Cd
19.5 15.7 63.6
Test
Cd
2.9 2.2 2.9
Pit Location
Cu
19 17 1 15
Pit Location
Cu
39 46 301
Pit Location
Cu
47 49 193
Pit Location
Cu
32 24 32
0608
Hg
0.84 ND 0.12
0701
Hg
0.20 0.15 1.48
0702^
Hg
0.11 0.12 1.43
0703
Hg
0.11 0.12 0.17
Mn
263 291 203
Mn
356 409 359
Mn
338 387 341
Mn
370 347 270
Ni
15 14 13
Ni
22 22 49
Ni
17 20 37
Ni
18 18 16
Pb
8.3 7.0 6.3
Pb
4.6 34.6 92.7
Pb
23.5 34.6 68.1
Pb
50,3 30.5 17.6
Zn
48 34 30
Zn
102 168 359
Zn
113 136 250
Zn
94 54 114
RD/R15/017-2
Table 10 (continued)
Sampling Depth (inches)
0-4 4-8 8-15
Al
8,049 8,763 7,812
As
11.2 7.5 7.7
Ba
184 136 159
Test
Cd
15.3 1.3 1.7
Pit
-
Location
Cu
45 19 20
0705
Hg
0.21 0.12 0.12
Mn
337 356 370
Ni
17 14 15
Pb
24,5 5.9 32.8
Zn
94 37
116
Field duplicates of Location 0701. Note: All concentrations reported on an oven dry basis, ND = Not detected at a concentration greater than 0.11 mg/kg.
OJ RD/R15/017
RD/R15/017-3
Sludge Bed No. 1, the larger bed to the west, did not contain any samples exceeding the ADEQ soil action limits for total chromium. A sample was collected from one location at a depth of 4 to 8 inches that contained a total chromium concentration of 525 mg/kg as shown on Table 11. With the exception of the surface 0- to 4-inch samples, and the samples collected from 4 inches to 15 inches from Location 0601, none of the remaining samples appeared to contain total chromium concentrations in excess of preliminary background data.
Soil samples collected from Sludge Bed No. 2, the smaller bed to the east, contained concentrations of total chromium in excess of twenty times the ADEQ soil action limit. As shown on Table 12, with the exception of Locations 0705 and 0706, the greatest concentrations of total chromium (32,243 mg/kg) occurs at a depth from 8 inches to 45 inches.
The samples from either sludge bed that contained greater than 500 mg/kg of total chromium are currently being analyzed with water soluble chromium elution and EP Toxicity tests to evaluate the solubility of the chromium present in the soils at the former GAC facility.
RD/R91/040 35
Table 12 CHROMIUM CONCENTRATIONS FROM GAC SLUDGE DRYING BED NUMBER 2
(mgAg)
OJ CTi
Sample Depth
(inches)
0 -
4 -
8 -
15 -
30 -
45 -
60 -
90 -
4
8
15
30
45
60
90
120
0701
478
461
23,290
26,072
3,194
44
62
46
0702^
615
513
13,847
32,243
7,022
44
74
60
0703
184
83
134
3,642
27,843
38
36
30
Test Pit Location
0704
133
515
2,861
7,134
30
45
32
49
0705
398
17
16
56
17
17
16
17
0706
131
25
22
18
15
17
20
23
0707
2,184
62
1,311
8,159
29,461
63
55
39
All data reported on an oven dried basis.
Field duplicates of Location 0701,
RD/R88/027-2
Of the remaining locations where soil samples were collected for total chromium analyses, none contained elevated total chromium concentrations (Tables 13, 14, 15, and 16).
FUTURE ANALYSES
Currently, analyses on those samples that contained contaminants in excess of the threshold concentration values for additional soil property tests are being completed. Once the results from these analyses are complete, the data will be used for investigating the possible soil/contaminant relationships that may exist at the site. The data will also be used to more accurately define the site's stratigraphy.