APPENDIX I SOIL QUALITY ANALYSIS
This appendix supplements the information presented in the Soil and Sediment Quality at Solid Waste Management Units and 1994 Annual Soil and Sediment Sampling, section 4.5.1, Affected Environment for Geology and Soils.
I.1 SOIL QUALITY
I.1.1 Soil and Sediment Quality at Solid Waste Management Units
Resource Conservation and Recovery Act (RCRA) Facility Investigations (RFIs) are currently being conducted at Pantex Plant, as described in section 4.5.1.3 in volume I. The RFIs include characterization of the nature and extent of contamination at a number of Solid Waste Management Units (SWMUs) associated with the 14 waste release site groupings that have been identified at Pantex Plant. Table I.1.1-1(.pdf) summarizes the SWMUs contained in each grouping and provides a brief description (Pantex 1996:15.1). RFIs have been completed for 5 of the 14 groupings, which include AL-PX-01 (Burning Ground), AL-PX-02 (High Priority Potential Release Sites), AL-PX-06 (Zone 12 Groundwater), AL-PX-08 (Ditches and Playas), and AL-PX-12 (Miscellaneous Chemical Spills/Releases). Table I.1.1-2(.pdf) summarizes the actions taken and recommendations from the five completed RFIs.
I.1.2 1994 Annual Soil and Sediment Sampling
Soil quality data were reviewed to evaluate the current soil quality at Pantex Plant Site and to compare current soil quality with historical data. This section presents the data and discusses the results of routine and nonroutine (special request) surface soil surveillance at Pantex Plant. The routine soil surveillance program plays an important role in assessing the potential environmental impacts of operations at Pantex Plant. Soil surveillance provides a direct measure of environmental contamination because soil accumulates contaminants that are deposited from the air over time. Thus, soil surveillance allows evaluation of long-term trends (DOE 1995b:12-1). This sampling program is conducted on an annual basis and is separate from the environmental restoration programs which deal specifically with SWMU sampling conducted under RCRA and the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) as discussed in section 4.5.1, Soil and Sediment Quality at Solid Waste Management Units.
I.1.2.1 Overview of Methods
From 1988 to 1993, 19 onsite and 32 offsite soil samples were collected annually in five different "routine" areas and analyzed for radionuclides, as summarized in Table I.1.2.1-1. The five areas included Firing Sites 4, 5, and 10, the Burning Ground, and offsite sampling locations. Figures I.1.2.1-1, I.1.2.1-2, and I.1.2.1-3 present the sampling locations. It should be noted that the soil data collected between 1988-1993 do not necessarily include every sample location for each year (DOE 1995b:12-1 through 12-4).
Figure I.1.2.1-1. Sampling Locations in the Vicinity of the Firing Sites and Burning Ground
Figure I.1.2.1-2. Offsite Soil Sampling Locations
Figure I.1.2.1-3. Soil Sampling Locations at Playas 1, 2, and 3.
The soil data collected for radionuclides were compiled, summarized, and distributed annually in the Environmental Report for Pantex Plant (also referred to as Annual Site Environmental Report [ASER]) (DOE 1995b). From 1988 to 1992, beryllium was the only non-radiological contaminant that was sampled and analyzed. It was thought that soil might have been contaminated with beryllium as a result of destructive testing of high explosive test configurations containing beryllium components. Areas included in the sampling program included the three firing sites, the Burning Ground, and offsite locations. Soil was not sampled for beryllium in 1993 or 1994.
During 1994, soil was routinely sampled at 31 onsite and 17 offsite locations. These samples were generally collected from playa bottoms and interplaya uplands. Depending on the location, soil samples were collected monthly or quarterly. Sample locations are shown in Figures I.1.2.1-1, I.1.2.1-2, and I.1.2.1-3 (DOE 1995b:12-1).
Due to a special DOE request, soil data locations for the 1994 ASER were expanded to include "non-routine" sample locations and chemicals of potential concern (COPC) (DOE 1995b:12-1). New areas of sample locations, number of samples collected, and COPC are summarized in Table I.2.1-2. Further detail for these data is presented in Tables I.1.2.1-3(.pdf), I.1.2.1-4(.pdf), and I.1.2.1-5 and Figures I.1.2.1-1 and I.1.2.1-2.
Average sample concentrations for radionuclides and uranium ratios in each area were calculated. In the case of discrepancies, the values provided in the ASER prevailed. Calculations for these values are provided in Table I.1.2.1-6.
In order to evaluate chemical concentrations, the average sample result from each sample location was compiled in electronic spreadsheet tables. Sample results below detection limits were omitted from evaluation. Chemical concentrations were then evaluated in two tiers:
First-The "Cleanup" levels (dated 4/94) for chemicals of concern at Pantex Plant. These levels are based on TNRCC Risk Reduction Standards (DOE 1994).
Second-The Risk-Based Concentration (RBC) Table (dated 1/95) provided by Environmental Protection Agency (EPA) Region III (EPA 1995).
Tables I.1.2.1-3(.pdf), I.1.2.1-4(.pdf), and I.1.2.1-5 present COPCs, "cleanup" levels, and RBCs.
I.1.2.2 Assumptions
The following assumptions were made for the soil quality evaluation:
- Collection of each soil sample consistently occurred at the same location over the duration of the sampling program.
- Sample collection and analysis conformed to State sampling procedures and EPA-approved methodologies. Sample results are assumed to be valid.
- Chemical concentrations were assumed to be representative of the soil sampling locations.
I.1.2.3 Data Source
The 1988 to 1994 ASERs were used as the data source for concentrations of COPC in soils. "Cleanup" levels from TNRCC, RBCs from EPA Region III, and preliminary remediation goals (PRGs) from EPA Region IX were compared with the sampling results.
I.1.2.4 Conclusions
The following conclusions were made based on the information presented in the previously shown tables and Tables I.1.2.4-1, I.1.2.4-2(.pdf), and I.1.2.4-3:
- Radionuclides: Soil samples were collected at three firing sites (4, 5, and 10), the Burning Ground, three playas (1, 2, and 3), and offsite locations, then analyzed for uranium-234, uranium-238, plutonium 239/240, and tritium. Based on the uranium-234:uranium-238 ratio, the highest level of depleted uranium appears to be located at Firing Sites 4, 5, and 10. The averages for 1994 for uranium-234 and -238 were lower than the averages of historical levels. Average concentrations of plutonium-239/240 in 1994 were similar to historical Bushlands averages, indicating no detectable contamination from Pantex Plant in area soils. The results are presented in Table I.1.2.1-2 and summarized in Table I.1.2.1-5. TNRCC or EPA concentration guidelines were not available.
- Metals: Soil samples were collected
at the Burning Ground, Playa 3, and offsite locations, then analyzed
for aluminum, boron, cadmium, chromium, cobalt, copper, magnesium,
manganese, molybdenum, mercury, nickel, silver, and zinc. The
results and TNRCC/EPA concentration levels are presented in Table I.1.2.1-2 and summarized in Table I.1.2.1-6.
TNRCC and EPA concentration
levels were not available for magnesium.
All metals, with the exception of manganese, were below TNRCC and EPA levels. Taking into account the deviations, 11 of the 12 soil samples collected from the Burning Ground were over the RBC residential levels for manganese. It should be noted that two of the offsite results were also higher than residential levels. - Explosives: Soil samples were collected at the Burning Ground, Playa 3, and offsite locations, then analyzed for high melting explosives (HMX), research developed explosives (RDX), pentaerythritol tetranitrate (PETN), and trinitrotoluene (TNT). The majority of results were nondetects. In accordance with guidelines of the National Pollutant Elimination Discharge System (NPDES) and hazardous waste permits, analytical results for groundwater samples are reported to the action levels defined in USEPA SW-846 Method 8330 for the determination of presence and concentration of high explosives (Pantex 1996:4.9). These results that were above detection limits were all below TNRCC and EPA levels. The results and the TNRCC/EPA concentration levels are presented in Table I.1.2.1-5 and summarized in Table I.1.2.4-3.
- Volatile Organic Compounds (VOCs): Soil samples were collected at Playa 3 and offsite locations. None of the VOCs were found at levels above the minimum detection limits. Based on these results, no additional analysis was performed.
REFERENCES
References for Appendix I (.pdf)
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