In 1998, carbon tetrachloride was found above the maximum contaminant level (MCL) of 5 {micro}g/L in groundwater from one private livestock well at Sylvan Grove, Kansas, by the Kansas Department of Health and Environment (KDHE). The 1998 KDHE sampling was conducted under the U.S. Department of Agriculture (USDA) private well sampling program. The Commodity Credit Corporation (CCC), a USDA agency, operated a grain storage facility in Sylvan Grove from 1954 to1966. Carbon tetrachloride is the contaminant of primary concern at sites associated with former CCC/USDA grain storage operations. Sylvan Grove is located in western Lincoln County, approximately 60 mi west of Salina (Figure 1.1). To determine whether the former CCC/USDA facility at Sylvan Grove is a potential contaminant source and its possible relationship to the contamination in groundwater, the CCC/USDA has agreed to conduct an investigation, in accordance with the Intergovernmental Agreement between the KDHE and the Farm Service Agency (FSA) of the USDA. This Work Plan presents historical data related to previous investigations, grain storage operations, local private wells and public water supply (PWS) wells, and local geologic and hydrogeologic conditions at Sylvan Grove. The findings from a review of all available documents are discussed in Section 2. On …

The Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility at the western edge of Everest, Kansas, from the early 1950s to the early 1970s. Sampling by the Kansas Department of Health and Environment (KDHE) in 1997 resulted in the detection of carbon tetrachloride in one domestic well (the Nigh well) northwest of the former facility. On behalf of the CCC/USDA, Argonne National Laboratory subsequently conducted a series of investigations to characterize the contamination (Argonne 2003, 2006a,b,c). Automatic, continuous monitoring of groundwater levels began in 2002 and is ongoing at six locations. The results have consistently indicated groundwater flow toward the north-northwest from the former CCC/USDA property to the Nigh property, then west-southwest from the Nigh property to the intermittent creek. Sitewide periodic groundwater and surface water sampling with analysis for volatile organic compounds (VOCs) began in 2008. Argonne's combined data indicate no significant downgradient extension of contamination since 2000. At present, the sampling is annual, as approved by the KDHE (2009) in response to a plan developed for the CCC/USDA (Argonne 2009). This document presents a plan for collecting indoor air samples in homes located along and adjacent to the defined extent of …