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SWMU I-1 RCRA Facility Investigation Report
Section 2 - Field Investigation
As outlined in the Environmental Encyclopedia site-specific work plan (Volume 1‑2, SWMU I-1), the objectives of the RFI were to conduct a geophysical survey, conduct a soil gas survey, collect three grab surface soil samples at a depth of six inches below surface grade, advance and sample three soil borings, and collect one surface wipe sample from inside Building 294. All field activities were conducted in accordance with the Field Sampling and Analysis Plan (Volume 1-5, Field Sampling Plan, Quality Assurance Project Plan, and RL83 Addendum).
The soil boring location points were surveyed by Parsons using a Trimble Asset-grade Global Positioning System (GPS) tool. Soil gas and soil sample location points were located using detailed field maps and notes. As such, a slight margin of error should be considered for these data. All sample location points and corresponding analytical data have been incorporated into the CSSA GIS database.
Electromagnetic (EM) geophysical surveys were conducted at SWMU I-1 in March 1996. Prior to collecting EM data, a grid system was established at the site that encompassed the areas of suspected ground disturbance. These grids consisted of staked locations separated by intervals ranging from 25 to 100 feet, depending on the size of the area and the amount of obstructions, if any.
EM data were collected at 2-foot intervals along transects that were separated by 10 feet using the established geophysical survey grid. EM measurements were taken using a Geonics EM31-DL ground conductivity meter, and recorded with a Polycorder data logger. The conductivity meter consists of transmitter and receiver coils that are separated by 12 feet. The instrument has a nominal depth of penetration of approximately 16 feet when operated in the vertical-dipole mode. The instrument measures both quadrature- and in-phase components of an induced magnetic field. The quadrature-phase component is a measure of apparent ground conductivity while the in-phase component is more sensitive to the presence of ferromagnetic metal. A lateral variation in apparent ground conductivity indicates a lateral change in subsurface physical properties (i.e., related to degree of disturbance). Apparent ground conductivity is measured with a precision of approximately ±2 percent of the full-scale meter reading which corresponds to approximately 2 milliSiemens per meter (mS/m). The in-phase component of the EM-31 is the response of the secondary to primary magnetic field measured in units of parts per thousand (ppt). The primary magnetic field is due to the current source from the EM-31. The secondary magnetic field is due to induced currents within conductive material in the subsurface.
Data were collected by setting the instrument to record in an automatic vertical dipole mode. Readings were taken at 0.5 second intervals which corresponded to a reading every 2 feet along a given transect. Both apparent ground conductivity (i.e., quadrature phase) and in-phase data were recorded. The operator aligned himself along a transect and, with the instrument parallel to the transect, paced between marked or staked stations separated by 10 feet.
The EM-31 survey was completed according to the procedures described in Volume 1-4, Sampling and Analysis Plan, Section 1.1.2. Prior to the survey, a site near the SWMU that was determined to be free of disturbances and anomalies was selected and marked to perform background checks and calibration. The background checks were also performed after the survey. All calibration and before- and after-background readings were recorded in the field logbook.
During each field day, data were transferred from the data logger to computer diskettes. The data were processed using DAT31 software (Geonics, LTD) and contoured using Surfer software. Contour maps for both quadrature phase (apparent conductivity) and in-phase data were created for each site.
Soil gas sampling took place on August 22 and 23, 1996. A total of 13 samples were collected from locations adjacent to building 294 and in the areas north and east of the SWMU (Figure I1-4). As shown in Figure I1-4, seven soil gas samples and one duplicate were collected within the boundary, and four samples and one duplicate were collected north and east of the site.
Soil gas probes were driven to the bedrock-soil interface or until refusal (approximately 5 feet). Samples were collected by manually driving a hollow, decontaminated ¾-inch stainless steel sampling rod to the selected depth with a pneumatic hammer. The sampling rod was then backed a few inches out of the ground allowing the detachable point to drop off the sampling probe and exposing a void space of the formation. Soil vapors were then pulled from the soil through the probe into a tedlar bag using a portable vacuum pump. The soil formation around the sample rod was purged for at least three probe volumes prior to sample collection. The samples were then transported to the field gas chromatograph (GC) temporarily located at CSSA for analysis. Samples were analyzed within four hours of collection. After sampling, probes were decontaminated for use at another location. Decontamination procedures consist of washing off the probes with Alconox and water, rinsing and allowing the probes to air dry.
An initial screening of the soil gas samples was performed in the field by scanning the exhaust from the vacuum pump with an HMX-271 explosimeter for oxygen content. Each sample was analyzed for benzene, toluene, ethyl benzene, total xylenes, cis‑1,2-dichloroethene (DCE), trichloroethene (TCE), and tetrachloroethene (PCE) using an HNu model 321 GC equipped with an electron-captor detector and a photoionization detector (PID) with a 10.2 electron-Volt (eV) light source. A Spectra-Physics model 4400 dual-channel integrator was used to plot the chromatograms, to measure the size of the peaks, and to compute compound concentrations. The chromatographic column used for analysis is a 12-foot long, 1/8-inch diameter stainless steel packed column containing 3 percent OV-101 Chromosorb W-HP packing material with a 100/120 mesh particle size.
Three surface soil samples were collected at SWMU I-1 in April 2000. The samples were collected from locations (Figure I1-4) identified as the most likely to be contaminated by COCs. Samples I1-SS01 and I1-SS02 were collected on the east and west side respectively of the incinerator stack. The incinerator stack is located on the south side of Building 294 and the samples were collected near the ash collector access doors. The third sample, I1-SS03, was collected on the north side of Building 294.
All samples were collected from the first 0.5 feet of the soil column by using a decontaminated hand trowel. The samples were submitted to APPL Laboratories in Fresno, California on April 27, 2000 for analysis of PCBs using EPA method SW8082.
The SWMU I-1 soil samples originated from the Krum Complex soil type. In general, the soils were stiff, moist, calcareous clays with a measurable gravelly component (less than 25 percent). At the time of sampling, no discernable evidence of contamination was noted.
All decontamination, sample preparation and handling followed those protocols established in the Field Sampling and Analysis Plan (Volume 1-5, Field Sampling Plan, and RL53 Addendum). All sample locations and analytical data have been incorporated into the CSSA GIS.
In March 2000, three soil borings were advanced and soil/rock samples were obtained at three discrete intervals from each boring. The uppermost sample collected from each soil boring (SB) was from 0.5-1.0 feet bgs. The three soil borings were designated I1-SB01, I1-SB02, and I1-SB03. I1-SB01 was placed approximately four feet north of Building 294, while I1-SB02 was placed approximately eight feet from the southwestern corner of the building. I1-SB03 was placed approximately six feet south of the incinerator building (Figure I1-4). I1-SB01 was advanced to 15 feet bgs, I1-SB02 was advanced to 6 feet bgs, and I1-SB03 was advanced to 14 feet bgs.
The borings were drilled in areas that would accurately characterize the nature of the material underlying the SWMU. Samples collected above the bedrock were obtained using a decontaminated hollow-stem auger and split-spoon sampler. Rock samples were obtained by air core rotary drilling using a decontaminated core barrel. All decontamination, sample preparation, and sample handling followed those protocols established in the Field Sampling and Analysis Plan (Volume 1-5, Quality Assurance Project Plan). Environmental sampling also included the collection and submittal of quality assurance/quality control (QA/QC) at those frequencies outlined in the AFCEE Quality Assurance Project Plan (QAPP) (Volume 1-4, Quality Assurance Project Plan).
All soil boring samples were analyzed by APPL Laboratories for VOCs (SW-8260B); arsenic (SW-7060A); cadmium (SW-7131A); lead (SW-7421A); mercury (SW-7471A); and barium, chromium, copper, nickel, and zinc (SW-6010B). A total of nine environmental samples, two field duplicates, one equipment blank, two trip blanks, one matrix spike, and one spike duplicate were submitted for analyses. At the time of sampling, no discernable evidence of contamination was noted during the sampling activities.
All soil boring locations were surveyed by Parsons using a Trimble Asset-grade GPS. All soil boring locations and analytical data have been incorporated into the CSSA GIS.
In accordance with the approved work plan, groundwater samples were not collected in association with the current SWMU I-1 investigation since there was none encountered during drilling operations.
One surface wipe sample was collected on March 21, 2001 from SWMU I-1 for this investigation. The wipe sample was collected from an area blackened with soot inside the incinerator. The wipe sample was sent to Triangle Laboratories in Durham, North Carolina and analyzed for dioxins and furans using EPA test method 8290.
The geophysical surveys revealed no evidence of subsurface anomalies related to past waste management activities. Both the in-phase and the quadrature phase portions of the EM survey revealed anomalies related to structures and underground utilities. Anomaly A (Figure I1-5 and Figure I1-6), which is located on the north and southeastern side of Building 294, was identified as a sewer line leading to the nearby sewage treatment facility located south of SWMU I-1. Anomaly B (Figure I1-5 and Figure I1-6), located south of Building 294, was identified as an underground electrical utility line.
Thirteen soil gas samples were collected from eleven sample locations throughout SWMU I-1. Sample locations A,0 and C,1 had duplicate samples collected for quality assurance purposes. In addition to the soil gas samples that were analyzed, system blank samples and ambient air samples were analyzed as well. Soil gas sample results are provided in Table I1-1.
None of the samples collected at this site had detectable concentrations of the target analytes. This suggests that there is not a significant source of volatile organic compounds within the survey area of SWMU I-1.
As described in Section 2.1.3, three surface samples collected from SWMU I-1 were analyzed for PCBs. No PCBs were detected in the samples at a method detection limit of 0.001 mg/kg. A complete listing of the laboratory results is provided in Appendix A.
The three soil borings that were advanced near Building 294 were each sampled at three discrete intervals, totaling nine samples. The nine samples were all analyzed for metals (barium, chromium, copper, nickel, zinc, arsenic, cadmium, lead, mercury) and VOCs.
Six of the boring samples (the uppermost samples from each boring) consisted of soil, while the remaining three samples consisted of Lower Glen Rose Limestone material. None of the soil samples exceeded RRS1 metal standards (Table I1-3). The highest metal concentration detected among the samples occurred in I1-SB03 (0.5-1.0 feet bgs), with a barium concentration of 110.74 mg/kg (value is J-flagged). The RRS1 standard for barium in soils is 186 mg/kg. The six soil samples had only one reported VOC concentration that exceeded applicable RRS1 (laboratory RL) criteria. The concentration occurred in I1-SB01 (0.5-1.0 feet bgs), with dichlorodifluoromethane reported at a concentration of 0.1451 mg/kg. The RRS1 standard (RL) for dichlorodifluoromethane in this sample is 0.0066 mg/kg.
Three of the nine total samples taken from the three borings consisted of Lower Glen Rose Limestone. With respect to metals, only one of the samples exceeded RRS1 standards (Table I1-2). The RRS1 standard for arsenic in the Glen Rose Formation is 3.86 mg/kg. In sample I1-SB02 (5.5-6 feet bgs), eight metals exceeded RRS1 standards, barium, chromium, copper, nickel, zinc, arsenic cadmium, and lead. Reported concentrations for barium, chromium, copper, nickel, zinc, arsenic, cadmium, and lead are 106.76 mg/kg, 26 mg/kg, 14.16 mg/kg, 26.55 mg/kg, 25.4 mg/kg, 9.33 mg/kg, 0.10 mg/kg, and 30.56 mg/kg. The reported concentrations for barium, nickel, arsenic, and lead were J-flagged. No VOCs exceeded applicable RRS1 standards for the Glen Rose Limestone samples.
In accordance with the approved work plan, groundwater samples were not collected in association with the current investigation conducted for SWMU I-1.
The surface wipe sample collected within the incinerator was analyzed for dioxin and furans for an assessment of potential impact to surrounding media. The surface wipe sample analytical results indicate very slight presence (<0.05 ng/cm2) of total hepta chloro dibenzodioxin (HpCDDs) and total hepta, hexa, peca, and tetra chloro dibenzofurans.
It is suspected that these dioxins and furans are the result of waste paper incineration burned inefficiently and at lower temperatures than modern incinerators. According to the EPA, incinerators are the largest industrial source of emission of dioxins and furans to the environment (EPA, 1998).
The presence of dioxins and furans is not unexpected. However, the levels at which they were quantified does not warrant investigation of their presence within the surrounding media. Although there is no TCEQ standard for dioxins and furans, the levels within the incinerator are extremely low and do not suggest that the surrounding soil would be affected. Therefore, no additional samples of the soil matrix surrounding Building 294 (SWMU I-1) were analyzed for dioxins and furans.