Corrective Action Decision Document/Closure Report for Corrective Action Unit 232: Area 25 Sewage Lagoons, Nevada Test Site, Nevada

This Corrective Action Decision Document/Closure Report (CADD/CR) has been prepared for Corrective Action Unit (CAU) 232, Area 25 Sewage Lagoons, in accordance with the Federal Facility Agreement and Consent Order. Located at the Nevada Test Site in Nevada, approximately 65 miles northwest of Las Vegas, CAU 232 is comprised of Corrective Action Site 25-03-01, Sewage Lagoon. This CADD/CR identifies and rationalizes the U.S. Department of Energy, Nevada Operations Office's (DOE/NV's) recommendation that no corrective action is deemed necessary for CAU 232. The Corrective Action Decision Document and Closure Report have been combined into one report because sample data collected during the July 1999 corrective action investigation (CAI) activities disclosed no evidence of contamination at the site. Contaminants of potential concern (COPCs) addressed during the CAI included total volatile organic compounds, total semivolatile organic compounds, total Resource Conservation and Recovery Act metals, total pesticides, total herbicides, total petroleum hydrocarbons (gasoline and diesel/oil range), polychlorinated biphenyls, isotopic uranium, isotopic plutonium, strontium-90, and gamma-emitting radionuclides. The data confirmed that none of the COPCs identified exceeded preliminary action levels outlined in the CAIP; therefore, no corrective actions were necessary for CAU 232. After the CAI, best management practice activities were completed and included installation of a fence and signs to limit access to the lagoons, cementing Manhole No. 2 and the diverter box, and closing off influent and effluent ends of the sewage lagoon piping. As a result of the CAI, the DOE/NV recommended that: (1) no further actions were required; (2) no Corrective Action Plan would be required; and (3) no use restrictions were required to be placed on the CAU