Streamlined Approach for Environmental Restoration (SAFER) Plan for Corrective Action Unit 356: Mud Pits and Disposal Sites, Nevada Test Site, Nevada (Revision No. 0, August 2001)

摘要

This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the actions necessary for the characterization and closure of Corrective Action Unit (CAU) 356, Mud Pits and Disposal Sites, as identified in the Federal Facility Agreement and Consent Order (FFACO). The CAU, located on the Nevada Test Site in Nevada, consists of seven Corrective Action Sites (CASs): CAS 03-04-01, Area 3 Change House Septic System; CAS 03-09-01, Mud Pit Spill Over; CAS 03-09-03, Mud Pit; CAS 03-09-04, Mud Pit; CAS 03-09-05, Mud Pit; CAS 20-16-01, Landfill; CAS 20-22-21, Drums. Sufficient information and process knowledge from historical documentation and investigations are the basis for the development of the phased approach chosen to address the data collection activities prior to implementing the preferred closure alternative for each CAS. The Phase I investigation will determine through collection of environmental samples from targeted populations (i.e., mud/soil cuttings above textural discontinuity) if contaminants of potential concern (COPCs) are present in concentrations exceeding preliminary action levels (PALs) at each of the CASs. If COPCs are present above PALs, a Phase II investigation will be implemented to determine the extent of contamination to support the appropriate corrective action alternative to complete closure of the site. Groundwater impacts from potentially migrating contaminants are not expected due to the depths to groundwater and limiting hydrologic drivers of low precipitation and high evaporation rates. Future land-use scenarios limit future uses to industrial activities; therefore, future residential uses are not considered. Potential exposure routes to site workers from contaminants of concern in septage and soils include oral ingestion, inhalation, or dermal contact (absorption) through in-advertent disturbance of contaminated structures and/or soils. Diesel within drilling muds is expected to be the primary COPC based on process knowledge. Recirculation processes within the mud pits enhance volatilization of volatile organic compounds (VOCs), thereby reducing the potential concentrations of any VOCs that may be present. A secondary source of contaminants from random truck dumping activities and leaking vehicle discharge may have released fuels, grease, motor oil, and hydraulic fluids into the mud pit effluent stream. Radionuclide contamination is not expected at these CASs based on historical information. The primary radioisotopes that could be expected, if present, are cesium-137, tritium, and strontium-90. The SAFER process ends with closure of the site based on the laboratory analytical results of the environmental samples. There is sufficient information and process knowledge from historical documentation regarding the expected nature and extent of potential contaminants to recommend closure of CAU 356 using the SAFER process. On completion of the field activities, a Closure Report will be prepared and submitted to the Nevada Division of Environmental Protection for review and approval.