Site Narrative:
In 1985, KDHE detected carbon tetrachloride concentration exceeding the Environmental Protection Agency (EPA) Maximum Contaminant Level (MCL) of 5 micrograms per liter (?g/L) in the Agra public water supply (PWS). Carbon tetrachloride was again detected above the MCL in PWS Well #4 in August 1986. KDHE conducted a Preliminary Site Assessment in 1987-1988 and confirmed the presence of nitrate and carbon tetrachloride in ground water of both public and private wells. The KDHE State Water Plan conducted a Site Assessment in 1993 showed carbon tetrachloride values above the MCL in a four of the five wells sampled. A Comprehensive Investigation (CI) in 1995 showed carbon tetrachloride in groundwater samples from both USDA and Pro-Ag Coop property to the south of the USDA site.
In 1995, Argonne National Laboratory (ANL), on behalf of the CCC/USDA, conducted a Phase I (June) and Phase II (October) Investigation at the USDA site but not on the Pro-Ag Co-op property. Results delineated a plume that originated from the USDA property.
A Corrective Action Study (CAS) under the State Water Plan was performed by in 1997-1998. Based on the analytical results of the CAS investigation, the former CCC/USDA property was identified as one of several probable sources of carbon tetrachloride contamination. KDHE reviewed a Feasibility Study (1997) submitted by CCC/USDA, and concluded that a supplementary investigation at the site was necessary prior to identification of viable corrective action alternatives. ANL conducted the fieldwork during the summer of 2005. The final report for the investigation (July 2006) identified three sources of carbon tetrachloride at the site, one from the USDA site and two from the Pro-Ag Coop
An Interim Measure (IM) submitted by CCC/USDA uses air sparge (AS) and soil vapor extraction (SVE) in large diameter borings to remediate source area soil and groundwater contamination. In December 2008 field work to install the borings, the IM system, and soil-gas monitoring wells commenced. The IM system has been operational since May 2009. Groundwater monitoring at the site began in 1998-1999 and continues today.
An Information Request letter was sent to Producers Agricultural Marketing, Inc.(Pro-Ag), owner of the coop property south (downgradient) of the Agra facility. Responses to the information request were received in January 2004. Pro-Ag has entered into a Consent Order to manage contamination at, and emanating from, its facility in Agra (Pro-Ag Agra Site, C6-074-72376). A Sitewide monitoring agreement between Pro-Ag Marketing and CCC/USDA was signed in May 2010. Annual sitewide sampling of wells was done in June 2009 and 2011, and July 2013 by CCC/USDA, and in August 2010 and June 2012 by Pro-Ag. July-December 2014 Progress Report regarding the LDB/SVE/AS action was approved in May 2015. January-June 2016 Progress Report regarding the LDB/SVE/AS was submitted and approved in September 2016.
The CAS was approved in July 2019. The Kansas Department of Wildlife, Parks, and Tourism approved discharge into Turner Creek, an ephemeral stream which eventually discharges Lake Agra on 9/9/2020. USDA continues to work with BOW regarding discharge and monitoring requirements.
The Corrective Action Dcision (CAD), in which KDHE selects the remedial selection for the Site, was made available to the public for comment from March 10 - April 10, 2021, with notice of availability printed in the Phillips County Review newspaper on March 10. No comments were received from the public. The selected remedy includes Groundwater Extraction, Treatment with a Tray Aerator, and Discharge (via NPDES or beneficial reuse); Groundwater Monitoring, and Five Year Reviews. The Final CAD and Declaration were signed by the Secretary on April 26, 2021. The USDA/CCC will submit a Corrective Action Plan detailing the plan for remedial implementation as the next step. |