Site Narrative:
Carbon tetrachloride was detected in a domestic well at 15.4 µg/L in February 1996 during a limited private well sampling conducted as part of an inventory of former Commodity Credit Corporation/United States Department of Agriculture (CCC/USDA) grain bin sites in Kansas. KDHE initiated a Site Reconnaissance Evaluation (SRE) in February 1997. During the SRE, nitrate was detected in five private wells and carbon tetrachloride was detected in one private well.
The State Water Plan program completed a Comprehensive Investigation (CI) in 1998. Nitrate was detected in the soil on the Montrose Grain property at 405 mg/kg. Analytical results from a private well downgradient of the CCC/USDA facility revealed carbon tetrachloride contamination at 5.1 µg/L (the Maximum Contaminant Level (MCL) for carbon tetrachloride established by the federal Safe Drinking Water Act is 5 µg/L). The final CI report, dated April 13, 1998, concludes the source of contamination at this site appears to be the former CCC/USDA grain storage facility. The CI report recommends ground water monitoring in selected domestic supply and monitoring wells at the site. Following this investigation, CCC/USDA submitted a work plan for a Phase I Investigation. This work plan states “data are presently insufficient to determine with certainty the predominant direction(s) of ground water flow at Webber.” Due to this uncertainty, CCC/USDA maintains that several additional sources must be considered. On November 2, 2001, KDHE approved the installation of ground water level recorders in the six KDHE monitoring wells on site.
On April 13, 2004, KDHE requested a comprehensive monitoring event be performed by USDA in order to assess current conditions at the site and to determine the necessary future actions. On March 23, 2005, KDHE received a Draft Work plan for Targeted Groundwater Sampling at Webber, Kansas. KDHE reviewed the document and requested additional groundwater sampling locations north and west of the former CCC/USDA facility on September 1, 2005. KDHE received the CCC/USDA response to comments on February 2, 2006. On February 3, 2006, KDHE approved the response but encouraged CCC/USDA to consider adding one or two additional sampling locations near the former CCC/USDA facility to assess plume orientation and to help position the down-gradient sampling and monitoring locations. On April 28, 2006, KDHE received a revised work plan for the site, which included additional soil and groundwater sampling locations. KDHE approved the document on May 16, 2006; however, per the request of CCC/USDA, fieldwork at Webber has been postponed at this time due to no access from the landowner of the former CCC/USDA facility property.
In January 2012 KDHE requested CCC/USDA develop a sampling plan to resample private wells near former CCC/USDA grain bin Sites in Kansas where no monitoring program currently exists. CCC/USDA requested that KDHE perform the sampling, and KDHE prepared/approved a Private Well Sampling Plan in December 2012 for the Site. KDHE implemented the CCC/USDA-sponsored Private Well Sampling Plan for the Site in March 2013; eleven private wells were sampled, with carbon tetrachloride detected in three of the samples collected at concentrations ranging from 2.1 to 6.2 µg/L. KDHE collected confirmation samples from one of the wells in July 2013 and carbon tetrachloride was not detected in the samples collected. CCC/USDA is currently monitoring groundwater quality in two private wells near the former CCC/USDA facility. KDHE has requested CCC/USDA revisit getting access to the former CCC/USDA facility property to implement the Site Investigation Work Plan. |