Corrective Action Decision Document/Closure Report for Corrective Action Unit 560: Septic Systems, Nevada Test Site, Nevada, Revision 0
Corrective Action Unit 560 comprises seven corrective action sites (CASs): •03-51-01, Leach Pit •06-04-02, Septic Tank •06-05-03, Leach Pit •06-05-04, Leach Bed •06-59-03, Building CP-400 Septic System •06-59-04, Office Trailer Complex Sewage Pond •06-59-05, Control Point Septic System The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure of CAU 560 with no further corrective action. To achieve this, corrective action investigation (CAI) activities were performed from October 7, 2008, through February 24, 2010, as set forth in the Corrective Action Investigation Plan for Corrective Action Unit 560: Septic Systems, Nevada Test Site, Nevada, and Record of Technical Change No. 1. The purpose of the CAI was to fulfill the following data needs as defined during the data quality objective (DQO) process: •Determine whether contaminants of concern (COCs) are present. •If COCs are present, determine their nature and extent. •Provide sufficient information and data to complete appropriate corrective actions. The CAU 560 dataset from the investigation results was evaluated based on the data quality indicator parameters. This evaluation demonstrated the quality and acceptability of the dataset for use in fulfilling the DQO data needs. Analytes detected during the CAI were evaluated against final action levels (FALs) established in this document. The following contaminants were determined to be present at concentrations exceeding their corresponding FALs: •No contamination exceeding the FALs was identified at CASs 03-51-01, 06-04-02, and 06-59-04. •The soil at the base of the leach pit chamber at CAS 06-05-03 contains arsenic above the FAL of 23 milligrams per kilogram (mg/kg) and polychlorinated biphenyl (PCBs) above the FAL of 0.74 mg/kg, confined vertically from a depth of approximately 5 to 20 feet (ft) below ground surface. The contamination is confined laterally to the walls of the leach pit chamber and leach rock. The contamination present at CAS 06-05-03 within the leach pit was not feasible to remove. •The surface and subsurface soils within and surrounding the septic system at CAS 06-05-04 contained PCB concentrations above the FAL of 0.74 mg/kg. The lateral and vertical extent of COCs was determined for this CAS. Contaminated soils were removed up to within 18 ft of the building. The remaining contamination is confined to subsurface soils adjacent to and beneath Building CP-162 and was not feasible to remove. •The solid materials within the septic tank and soils immediately surrounding the inlet end of the tank at CAS 06-59-03 contained benzo(a)pyrene above the FAL of 0.21 mg/kg. The soils, tank contents, and tank were removed. Materials remaining at this CAS do not contain contamination exceeding FALs. •The solids contained within the septic tank and inlet pipe at CAS 06-59-05 contained the following contaminants above their respective FALs: PCBs, arsenic, lead, benzo(a)pyrene, and pesticides. The tank and inlet pipe contents were removed. Materials remaining at this CAS do not contain contamination exceeding FALs. Therefore, the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) provides the following corrective action recommendations: •No further action for CASs 03-51-01, 06-04-02, and 06-59-04, as no contaminants of potential concern were present that exceed FALs. •Closure in place for CAS 06-05-03 under a corrective action with a use restriction (UR) for remaining PCB- and arsenic-impacted potential source material (PSM). The UR form and map have been filed in the NNSA/NSO Facility Information Management System, the FFACO database, and NNSA/NSO CAU/CAS files. •Closure in place for CAS 06-05-04 under a corrective action with a UR for remaining PCBs in soil adjacent to and beneath Building CP-162. The UR form and map have been filed in the NNSA/NSO Facility Information Management System, the FFACO database, and NNSA/NSO CAU/CAS files. •No further action for CAS 06-59-03, as the COC of benzo(a)pyrene in soil and PSM have been removed. •No further action for CAS 06-59-05, as the COCs in PSM within the septic tank and inlet piping have been removed and the tank was filled with concrete.
- Research Organization:
- Navarro Nevada Environmental Services
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DEAC5209NA28091
- OSTI ID:
- 978879
- Report Number(s):
- DOE/NV-1385; TRN: US201011%%78
- Country of Publication:
- United States
- Language:
- English
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