This Closure Report (CR) presents information supporting the closure of Corrective Action Unit (CAU) 566: EMAD Compound, Nevada National Security Site, Nevada. Corrective Action Unit 566 comprises Corrective Action Site (CAS) 25-99-20, EMAD Compound, located within Area 25 of the Nevada National Security Site. The purpose of this CR is to provide documentation supporting the completed corrective actions and provide data confirming that the closure objectives for CAU 566 were met. To achieve this, the following actions were performed: • Review the current site conditions, including the concentration and extent of contamination. • Implement any corrective actions necessary to protect human health and the environment. • Properly dispose of corrective action and investigation wastes. • Document Notice of Completion and closure of CAU 566 issued by the Nevada Division of Environmental Protection. From October 2010 through May 2011, closure activities were performed as set forth in the Streamlined Approach for Environmental Restoration Plan for CAU 566: EMAD Compound, Nevada National Security Site, Nevada. The purposes of the activities as defined during the data quality objectives process were as follows: • Determine whether contaminants of concern (COCs) are present. • If COCs are present, determine their nature and extent, implement appropriate corrective actions, and properly dispose of wastes. Analytes detected during the closure activities were evaluated against final action levels (FALs) to determine COCs for CAU 566. Assessment of the data from collected soil samples, and from radiological and visual surveys of the site, indicates the FALs were exceeded for polychlorinated biphenyls (PCBs), semivolatile organic compounds (SVOCs), and radioactivity. Corrective actions were implemented to remove the following: • Radiologically contaminated soil assumed greater than FAL at two locations • Radiologically contaminated soil assumed greater than FAL with lead shot • PCB-contaminated soil • Radiologically contaminated filters and equipment • Fuels, lubricants, engine coolants, and oils • Lead debris • Electrical and lighting components assumed to be potential source materials, including - fluorescent light bulbs - mercury switches (thermostats) - circuit boards - PCB-containing ballasts Closure of CAU 566 was achieved through a combination of removal activities and closure in place. Corrective actions to remove COCs, and known and assumed potential source materials, were implemented as was practical. The PCBs remaining at the site are bounded laterally, but not vertically, within CAS 25-99-20 based upon step-out sampling; the sources (e.g., PCB transformer oils, diesel fuel from locomotive reservoirs) have been removed; the practice of the application of PCB-containing oils for soil stabilization has ceased; and the COCs are not readily mobile in the environment. Closure in place is necessary, and future land use of the site will be restricted from intrusive activities. This will effectively eliminate inadvertent contact by humans with the contaminated media. The DOE, National Nuclear Security Administration Nevada Site Office, provides the following recommendations: • No further corrective action is required at CAS 25-99-20. • Closure in place of CAS 25-99-20. • A use restriction is required at CAU 566. • A Notice of Completion to the DOE, National Nuclear Security Administration Nevada Site Office, is requested from the Nevada Division of Environmental Protection for closure of CAU 566. • Corrective Action Unit 566 should be moved from Appendix III to Appendix IV of the Federal Facility Agreement and Consent Order.
