Site Narrative:
The USD 259 Site is located within the North Industrial Corridor Site in Wichita. The Site was identified in 1992 and was the subject of a 1993 Consent Order between USD 259 and KDHE for a Remedial Investigation (RI) and a 2002 Amended Consent Order for a Feasibility Study (FS). The RI for the Site was conducted in phases beginning in 1992. The RI report was approved by KDHE in November 2008 with the recognition that additional sampling to define the downgradient extent of the contaminant plume and assessment of vapor intrusion in nearby residences be conducted before proceeding with the FS for the Site.
The RI identified potential source areas, with the primary Site-related source area being a former underground storage tank (UST) basin, where apparent leakage of solvents occurred while the USTs were in use, and volatile organic compounds (VOCs) leached from impacted soils. Site constituents of concern identified during the RI include tetrachloroethene, trichloroethene, cis-1,2-dichloroethene, and vinyl chloride.
In 2000, USD 259 removed approximately 410 cubic yards of soil from the UST basin source area as a soil interim measure (IM). Sample results indicate that soil contamination extends beneath the school service center building. In 2004, USD 259 initiated groundwater IM activities (enhanced reductive dechlorination), which is addressed the downgradient core area of the plume and the area around the former UST basin located at the Site, including the impacted area under the building, where high concentrations of dissolved VOCs remained. Modifications of the injected material, locations, and quantities based on initial results of the ground water IM were made in February 2006.
In May 2011, KDHE approved plans for a full-scale groundwater IM consisting of additional injections and installation of a permeable reactive barrier (PRB). Additional injection work began in October 2011, and the installation of the PRB was completed in May 2012. The PRB construction report was approved with comment by KDHE in April 2014.
In June 2014, USD 259 submitted a Supplemental Source Area Investigation Work Plan and implementation began in Fall 2014. In July 2015, KDHE approved the Supplemental Source Area Investigation Report and the Enhanced In Situ Bioremediation Optimization Work Plan. Implementation of the Bioremediation Optimization Work Plan was initiated in late January 2016. A draft focused Feasibility Study was submitted in May 2017 and subsequently approved. KDHE drafted the Corrective Action Decision (CAD) for public comment and the CAD was finalized in May 2018. The selected remedy is currently being implemented, and groundwater monitoring is conducted annually. |