In 1985, carbon tetrachloride was discovered in the groundwater at Agra, Kansas, during routine sampling of public water supply wells. Two of Agra's four public water supply wells contained low but detectable levels of carbon tetrachloride; the concentrations in wells PWS-3 and PWS-4 exceeded the maximum contaminant level. These wells were removed from service in 1986, although they remain available for uses other than drinking water. Other public wells, outside the area of contamination, supply drinking water for the city of Agra. In 1987-2005, the Kansas Department of Health and Environment (KDHE) and the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) conducted investigations to delineate the contaminant plume and to identify source areas for the contamination - which results from the past use of grain fumigants containing carbon tetrachloride. Source areas were identified on the former CCC/USDA grain storage facility property and on the Producers Agricultural Marketing Association, Inc., property located to the south (Argonne 2006). The contaminant plume extends to the southeast, toward well PWS-3, from the identified source areas. Both the CCC/USDA and Pro-Ag Marketing are currently implementing KDHE-approved interim measures (IMs). To address the contamination identified on its former property, the CCC/USDA is implementing a source control IM consisting of large-diameter boreholes (LDBs) coupled with soil vapor extraction (SVE) and air sparging (AS). Pro-Ag Marketing plans to use groundwater extraction to address the downgradient plume. The CCC/USDA and Pro-Ag completed installation of the two interim measures in May 2009 and August 2009, respectively. The performance and assessments of the effectiveness of the IMs are being reported separately by the responsible entities. As part of the IM process, the KDHE (2008) requested the development of a joint sitewide groundwater monitoring plan to allow periodic assessment of the effectiveness of the separate IMs being implemented by the CCC/USDA and Pro-Ag, through monitoring of the level of contamination and the resulting change in both the extent and internal configuration of the downgradient plume. A Joint Work Plan for Sitewide Monitoring was developed by the CCC/USDA through its technical consultant, Argonne National Laboratory, and was reviewed, approved, and signed by Pro-Ag Marketing and subsequently submitted to the KDHE on May 12, 2009. The KDHE (2009a) provided comments on the Joint Work Plan on May 27, 2009, requesting submission of a revised version. To minimize delays, the KDHE allowed the CCC/USDA to proceed with the scheduled annual sampling proposed in the Joint Work Plan. The sampling was to be conducted according to the previously approved low-flow sampling methodology (Argonne 2009). Argonne conducted the first annual sampling event for the CCC/USDA on June 15-16, 2009. The finalized, signed version of the Joint Work Plan provided to the KDHE on November 9, 2009, is in Appendix A. Table 1.1 lists the monitoring and public water supply wells to be sampled under the Joint Work Plan, plus the wells being sampled to monitor the respective IMs. The entity responsible for each monitoring element is indicated, along with well completion dates and well registration numbers. The subject of this report is the initial sitewide groundwater sampling event that occurred on June 15-16, 2009, under the Joint Work Plan.
Place Name coordinates. (May be approximate.)
Place Name coordinates. (May be approximate.)
