Corrective measures evaluation report for technical area-v groundwater.

Abstract

This Corrective Measures Evaluation Report was prepared as directed by the Compliance Order on Consent issued by the New Mexico Environment Department to document the process of selecting the preferred remedial alternative for contaminated groundwater at Technical Area V. Supporting information includes background information about the site conditions and potential receptors and an overview of work performed during the Corrective Measures Evaluation. Evaluation of remedial alternatives included identification and description of four remedial alternatives, an overview of the evaluation criteria and approach, qualitative and quantitative evaluation of remedial alternatives, and selection of the preferred remedial alternative. As a result of the Corrective Measures Evaluation, it was determined that monitored natural attenuation of all contaminants of concern (trichloroethene, tetrachloroethene, and nitrate) was the preferred remedial alternative for implementation as the corrective measure to remediate contaminated groundwater at Technical Area V of Sandia National Laboratories/New Mexico. Finally, design criteria to meet cleanup goals and objectives and the corrective measures implementation schedule for the preferred remedial alternative are presented. I, TA-II, TA-III, TA-IV, and TA-V) (Figure 1-1). TA-V, which has been operating since the 1960s, is a secured 35-acre research and testing area located immediately northeast of TA-III at SNL/NM. The facility conducts research and development of advanced nuclear reactors, simulation sources, reactor safety, energy-related programs, and nuclear weapons systems.The SNL/NM Environmental Restoration (ER) Project has reported concentrations of trichloroethene (TCE) exceeding the U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) in samples from TA-V monitoring wells since 1993. Since initial discovery of TCE in groundwater, the ER Project has voluntarily undertaken various activities to determine the nature and extent of groundwater contamination, particularly to identify potential sources of this contamination (SNL/NM 1999). Contaminants of concern (COCs) in TA-V groundwater include TCE, tetrachloroethene (PCE), and nitrate.The New Mexico Environment Department (NMED) issued a Compliance Order on Consent (COOC) (NMED 2004) to the DOE, which among other things identified TA-V as an area of groundwater contamination requiring completion of a Corrective Measures Evaluation (CME).The COOC directed that a CME Work Plan be developed to identify and outline a process to evaluate remedial alternatives for implementation at TA-V. The CME Work Plan was formally approved by the NMED in April 2004 (SNL/NM 2004a). Results of activities performed under the TA-V CME Work Plan are documented in this CME Report.The purpose of this CME Report is to select a preferred remedial alternative for implementation at TA-V based on the results of information gathered during the CME process. The CME was conducted to ascertain which remedial alternative would mo...