Characterization Report for Area 23, Building 650 Leachfield, Corrective Action Unit No. 94, Nevada Test Site - Revision No.: 1 - January 1998

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Characterization Report for Area 23, Building 650 Leachfield, Corrective Action Unit No. 94, Nevada Test Site U.S. Department of Eneigy

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This report has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831; prices Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA

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This report was prepared as an account of work sponsored by an agency of the United States Government Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or use fulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any spe cific commercial product, process, or service by trade name, trademark, manufac turer, or otherwise does not necessarily constitute or imply its endorsement, recom mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

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Portions of this document may be illegible electronic image products. Images are produced from the best available original

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CHARACTERIZATION REPORT FOR AREA 23, BUILDING 650 LEACHFIELD, CORRECTIVE ACTION UNIT NO. 94, NEVADA TEST SITE DOE Nevada Operations Office Las Vegas, Nevada

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CHARACTERIZATION REPORT FOR AREA 23, BUILDING 650 LEACHFIELD, CORRECTIVE ACTION UNIT NO. 94, NEVADA TEST SITE Industrial Sites Subproject Michael O. Giblin, Acting Project Manager Nevada Environmental Restoration Project

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Table of Contents List of Figures................................................................................................................................. iii List of Tables................................................................................................................................. iv List of Acronyms and Abbreviations............................................................................................. vi 2.0 Prior Field Investigation and Sampling Activities.............................................................. 6 2.1 Distribution Box Liquid Evaluations.................... 6 2.2 1992 Soil Sample from Below the Distribution Box.............................................. 7 2.3 1992 Piping Excavation Sampling ......................................................................... 7 2.4 Preliminary Subsurface Evaluation of the Leachfield............................................7 2.5 1994 Distribution Box and Laboratory 126 Discharge Line Operational Closure...................................................................................... 10 2.7 1995 Preliminary Subsurface Evaluation of the Distribution Box........................ 11 3.1 Soil Boring and Sampling............................................;....................................... 14 3.2 Geologic, Hydrologic, and Geotechnical Analysis................................................ 18 4.1 Subsurface Soil Sampling Results......................................................................... 19 4.1.2 Total and Toxicity Characteristic Volatile Organic Compounds........24 4.1.4 Total Petroleum Hydrocarbons and Polychlorinated Biphenyls........... 27 4.1.6 Paint Filter Test....................................................................................... 28 4.1.7 Hydrologic and Geotechnical Analysis Results....................................28 Table of Contents Page i of viii

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Table of Contents (continued) Table of Contents Page ii of viii 5.1 Quality Control Samples.................................. 5.1.1 Field Quality Control Samples........ 5.1.2 Laboratory Quality Control Samples 5.2 Quality Assurance Objectives Measurements . 6.0 Data Quality Assessment and Modeling...................... 6.1 Data Quality Assessment................................ Appendix A - Soil Boring Logs A-l

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Table of Contents Page v of viii List of Tables (Continued) Number Title Page 4-9 Summary of Saturated Hydraulic Conductivity Test Results.............................................31 4-10 Summary of Moisture Characteristics of the Initial Drainage Curve................................ 31 4- 11 Summary of Calculated Unsaturated Hydraulic Properties.............................................. 32 5- 1 Area 23, Building 650 Leachfield Field Quality Control Samples Collected for Laboratory Analysis...................................................................................34 5-2 OfF-Site Laboratory Precision Measurements for the Area 23, Building 650 Leachfield 1997 Subsurface Soil Sampling Activities.......................... ... 38 5-3 Off-Site Laboratory Accuracy Measurements for the Area 23, Building 650 Leachfield 1997 Subsurface Soil Sampling Activities............................ 39

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List of Acronyms and Abbreviations Table of Contents Page vi of viii American Society for Testing and Materials Below ground surface Centimeters) of water Corrective Action Unit U.S. Department of Energy U.S. Department of Energy, Nevada Operations Office U.S. Environmental Protection Agency Gram(s) per cubic centimeter Inductively Coupled Plasma Lockheed Analytical Services Laboratories, Inc.

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Table of Contents Page iv of viii List of Tables Number Title Page 2-1 Radionuclide Concentrations for Water Samples from the Building 650 Leachfield Distribution Box.........................................................................6 2- 2 1995 300-Minute Gamma Scan Analytical Results ...........................................................12 3- 1 1997 Subsurface Soil Sampling Chemical and Radiological Analytical Methods...........16 3- 2 1997 Subsurface Soil Sampling Hydrologic and Geotechnical AnalyticalMethods.... 16 4- 1 Soil Samples for Chemical and Radiological Analysis..................................................... 20 4-2 Radionuclide Laboratory Analysis Results Detected Above Normal Background for the Area 23, Building 650 Leachfield.......................... 23 4-3 Detected Total and Toxicity Characteristic Volatile Organic Compound Laboratory Analysis Results for the Area 23, Building 650 Leachfield Soil Samples.............................................................................25 4-4 Detected Toxicity Characteristic Metals Laboratory Analysis Results for the Area 23, Building 650 Leachfield Soil Samples...................................................27 4-5 Summary of Particle Size Characteristics......................................................................... 30 4-6 Summary of Initial Moisture Content, Dry Bulk Density, Wet Bulk Density, and Calculated Porosity Results.........................................................30 4-7 Summary of Particle Density/Specific Gravity and Shrinkage Test Results...................30 4-8 Summary of Atterberg Test Results 31

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Table of Contents Page iii of viii List of Figures Number Title Page 1 -1 Location of the Nevada Test Site..........................................................................................2 1-2 Location of the Area 23, Building 650 Leachfield................................................................3 1- 3 Area 23, Building 650 Leachfield Site Plan......................................................................... 4 2- 1 1992 and 1994 Piping Excavation Sampling Trenches and Sample Locations Area 23, Building 650 Leachfield....................................................................................... 8 2- 2 1994 Preliminary Evaluation Trench and Sample Locations 3- 1 Soil Boring Locations Area 23, Building 650 Leachfield..................................................15 6-1 Cross-Sectional View of the Contaminant Areas at the Area 23, Building 650 Leachfield...........................................................................43

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Table of Contents Page vii of viii List of Acronyms and Abbreviations (continued) MEK Methyl ethyl ketone NDB Not detected above normal background NDEP Nevada Division of Environmental Protection NTS Nevada Test Site PRO Preliminary remediation goal(s) QA Quality assurance QAPP Quality Assurance Project Plan RCRA Resource Conservation and Recovery Act RCT Radiological control technician REECO Reynolds Electrical & Engineering Company, Inc. RPD Relative percent difference SSSAJ Soil Science Society of America Journal SVOC Semivolatile organic compound(s) TPH-G Total petroleum hydrocarbon in the gasoline range TPH-D Total petroleum hydrocarbon in the diesel range VOC Volatile organic compound(s)

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Table of Contents Page viii of viii List of Acronyms and Abbreviations (continued) % cm3/cm3 Percent, cubic centimeter per cubic centimeter

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Corrective Action Unit (CAU) No. 94, Building 650 Leachfield, is an historic laboratory disposal unit located in Area 23 at the Nevada Test Site (NTS) in Nye County, Nevada (see Figures 1-1, 1 -2 and 1-3). The NTS, the former nuclear weapons testing area, is operated by the U.S. Department of Energy, Nevada Operations Office (DOE/NV). Building 650 Leachfield has been characterized under the requirements of the Resource Conservation and Recovery Act (RCRA), The objectives of this project were twofold: • Characterize subsurface conditions at the CAU with respect to the on-site disposal unit. • Provide sufficient information to develop a closure strategy for the leachfield. To this end, subsurface sampling was conducted in the vicinity of the piping above the distribution box, under and around the distribution box, and within the leachfield to accomplish the following goals: • Evaluate the condition of the surrounding sediment and determine if constituents of concern (COCs) were present in the subsurface. • Assess the potential for migration of COCs downward from the leachfield through the • Estimate the extent of contaminant migration (if present) from the leachfield. Soil and headspace samples were collected from all of the sampling locations at specified intervals in the soil borings during characterization activities. Detailed field observations of surface and subsurface conditions, including lithologic description of drill cuttings, were also

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Tonopah Nye County Site Air Force, Junction Las Vegas ------- Test Range area Location of the Nevada Test Site

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Modified from REECo. 1993 Piping leading to the leachfield SCALE Leachfield open drain piping Area 23, Building 650 Leachfield Site Plan

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To make this sampling report more concise, complete field documentation and laboratory data (such as Field Activity Daily Logs, Sample Collection Logs, Analysis Request and Chain-of-Custody Forms, soil sample descriptions, laboratory certificates of analyses, and headspace screening results) are not included. However, these documents are retained in project files and will be supplied upon request. Descriptions of the site history, waste, inventories, and previous characterization activities are discussed in detail in the RCRA Industrial Site Environmental Restoration Site Characterization Plan, Area 23, Building 650 Leachfield (DOE, 1997a) and, therefore, will not be repeated in this report.

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2.0 Prior Field Investigation and Sampling Activities The objectives of the various sampling efforts conducted in the past at the Building 650 Leachfield site have included evaluation of the presence, concentration, and extent of any contamination present within the liquid in the leachfield distribution box, the soil below the upper pipelines leading to the distribution box, the soil immediately below the distribution box, and the soil within the center of the leachfield. 2.1 Distribution Box Liquid Evaluations In 1988 and 1990, a total of six liquid grab samples were taken from the distribution box by Reynolds Electrical & Engineering Company, Inc. (REECo, 1993). The samples were analyzed for gross beta, gamma, and/or tritium, and the results of the sampling are summarized in Radionuclide Concentrations for Water Samples from the Building 650 Leachfield Distribution Box Sample Date Tritium

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2.2 1992 Soil Sample from Below the Distribution Box On October 15,1992, REECo collected a soil sample from below the distribution box by inserting an aluminum tube through the hole in the bottom of the box and downward approximately 10 to 15 centimeters (cm) (4 to 6 inches [in.]) into the underlying soil. The sample was analyzed at the Building 650 laboratory for gamma emitters. Analysis indicated the presence of cesium-137 at level for this radionuclide, and the cobalt-60 result is considered an indication of potential site contamination based on its background level. 2.3 1992 Piping Excavation Sampling In October 1992, REECo excavated three trenches east of Building 650 (REECo, 1993): one at each drain line (referred to as the north and south trenches) and one along the main leachfield line at the sewer manhole between the drain lines (referred to as the middle trench) (see Figure 2-1). Soil samples were obtained adjacent to the drain lines at three locations in the trenches. The samples from the south and middle trenches were analyzed for volatile organic compounds tritium, gamma scan, and plutonium while the sample from the north trench was only analyzed for SVOCs. The only constituents identified were methylene chloride and acetone at laboratory the south trench sample. Both of the radionuclide results are considered to be below background 2.4 Preliminary Subsurface Evaluation of the Leachfield In August and September 1994, IT conducted a preliminary evaluation of the Building 650 Leachfield (IT. 1995). The evaluation involved the excavation of two trenches across and along the two western leachfield drain pipes near the distal end of the leachfield. The trenches were excavated to a depth of approximately 3.7 meters (m) (12 feet [ft]) below ground surface and samples were collected from the trench profiles (see Figure 2-2 for the approximate locations of the trenches). A total of four soil samples in addition to one background sample and one field

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4M line disconnected Line plugged 3/1993and plugged 11/1992 Modified from REECo, 1993 Piping leading to the leachfield SCALE Leachfield open drain piping 1992 and 1994 Piping Excavation Sampling Trenches and Sample Locations Area 23, Building 650 Leachfield

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------------- Contour interval equals 1 foot 1994 Preliminary Evaluation Trench and Sample Locations Area 23, Building 650 Leachfield

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duplicate sample were collected and analyzed for VOCs using U.S. Environmental Protection Agency (EPA) Test Method 8240, SVOCs using EPA Test Method 8270, total petroleum hydrocarbons (TPHs) using EPA Test Method 418.1, TC metals using EPA Test Methods 6010 and 7000 (EPA, 1996), and radiological parameters using Standard Method 7110 (gross alpha and gross beta) and HAST 300,4.5.2.3 (gamma spec) (DOE, 1992). Sample LCH00007, taken from the bottom of the west end of Trench 1, was reported to contain Test Method 418.1 which is only used for gross screening for hydrocarbon compounds and cannot be used to substantiate the presence or absence of hydrocarbon contamination to the NDEP (EPA, 1996). It is likely that the results of an analysis using EPA Test Method 8015 Modified rather than Method 418.1 for TPH would have yielded lower results for the same sample (EPA, 1996). Sample LCH00008, taken from 2.4 to 3.6 m (8 to 10 ft) depth on the east end of Trench 1, was reported to contain 5 micrograms per kilogram (pg/kg) of methylene chloride. The methylene chloride is likely to be a laboratory contaminant based on: its very low concentration, the detection limit for methylene chloride (i.e., 5 pg/kg), and its lack of presence in any of the other samples. The analytical results did not indicate the presence of man-made radionuclides in the samples analyzed. 2.5 1994 Distribution Box and Laboratory 126 Discharge Line Operational In March and May 1994, closure activities were conducted by REECo on the Building 650 Leachfield distribution box and the Laboratory 126 discharge line going into the distribution box (REECo, 1994). The closure activities included plugging the discharge line into the distribution box with rapid-setting cement, hand excavation of the laboratory discharge line, sampling of soil at two locations along the line, and rerouting the line to the sanitary sewer. A total of four soil samples were collected on May 18, 1994, within two trenches excavated in the leachfield: two below a deteriorated pipe junction and two below the intersection of the laboratory discharge line and the main leachfield line (see Figure 2-1). A background soil sample was also collected in the vicinity of the helicopter pad, approximately 183 m (600 ft) southeast of the project site. The soil

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gamma scan, isotopic plutonium, and tritium. The results of the soil analyses indicated no chemical or radioactive COCs in the soil below the piping. In October and November 1994, a geophysical investigation was conducted at the Building 650 Leachfield (IT, 1996) with the following objectives: • Determine if leachate migration away from the leachfield has occurred. • Approximate the lateral boundaries and vertical extent of any plume present in the shallow • Locate shallow conductive zones in the vicinity of the leachfield potentially representing To accomplish these objectives, electromagnetic (EM) induction surveys were conducted at various transmitter/receiver intercoil spacings and system configurations, which provided for a qualitative interpretation of changing physical conditions with depth beneath the surface. Interpretation of the results of the survey suggested that there was no obvious subsurface fluid/leachate migration away from the leachfield. The 1997 subsurface investigation and sampling confirmed these results. 2.7 1995 Preliminary Subsurface Evaluation of the Distribution Box In February 1995, REECo used a GeoProbe sampling device to collect three samples from below the leachfield distribution box (Emer, 1995). The GeoProbe apparams used a hydraulic ram to drive a small-diameter core barrel through the hole in the bottom of the distribution box and into the underlying soil. Samples were collected from approximately 56 cm (22 in.), 112 cm (44 in.), and 168 cm (66 in.) below the base of the distribution box. The samples were analyzed for total and TC metals, gamma scan (20- and 300-minute), tritium oxide, and gross alpha/beta. The small sample volumes did not allow for additional analyses. The 300-minute gamma scan results indicated the presence of americium-241, cobalt-60, and cesium-137 in the soil to a depth of at least 168 cm …