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�•_�\`;1 GAVIN NEWSOM <br /> I•'"'�!�GOVERNOR <br /> JARED BLUMENFELD <br /> WSECRETARY FOR <br /> Water Boards <br /> _NVIRONMENTAL PROTECTION. <br /> Central Valley Regional Water Quality Control Board <br /> 25 August 2021 <br /> Joe Niland <br /> Lincoln Center Environmental Remediation Trust <br /> 3043 Gold Canal Drive, Suite 201 <br /> Rancho Cordova, CA 95670 <br /> CONCURRENCE WITH NORTHERN PARKING LOT REMEDIAL PLAN, LINCOLN <br /> VILLAGE SHOPPING CENTER, STOCKTON, SAN JOAQUIN COUNTY <br /> Central Valley Regional Water Quality Control Board (Central Valley Water Board) staff <br /> reviewed the 6 August 2021 Northern Parking Lot Remedial Plan (Remedial Plan) <br /> prepared by Geosyntec on behalf of the Lincoln Center Environmental Remediation Trust <br /> (Trust) for the Lincoln Village Shopping Center in Stockton (Site). The Remedial Plan was <br /> submitted pursuant to our 14 June 2021 review letter for the April 2021 Vapor Intrusion <br /> Assessment Report and the May 2021 Soil Vapor Assessment Report. The Remedial <br /> Plan includes an assessment of options for remediating tetrachloroethene (PCE) impacts <br /> in soil vapor. The Trust proposes remediating PCE concentrations near soil vapor probe <br /> SG-100 which contains concentrations up to 22,000 micrograms per cubic meter (ug/m3) <br /> to less than the original Site cleanup goal of 603 ug/m3. The impacts are in an area along <br /> a sewer lateral that was previously remediated by SVE but rebound may have occurred. <br /> The Remedial Plan also includes plans for additional groundwater remediation of PCE <br /> impacts in nearby groundwater monitoring wells MW-007A and MW-009A if soil vapor <br /> remediation is not effective in reducing PCE concentrations in those wells. <br /> Geosyntec evaluated a combination of soil vapor extraction (SVE), in-situ chemical <br /> oxidation (ISCO), and excavation as potentially applicable technologies to reduce the PCE <br /> concentrations in soil vapor to below the Site cleanup goal. Geosyntec determined that <br /> SVE was the most effective technology in addressing soil vapor impacts. Geosyntec also <br /> evaluated ISCO as a remedial alternative for nearby groundwater impacts if SVE is not <br /> effective in reducing deeper PCE impacts in the capillary fringe near MW-007A and <br /> MW-009A. Geosyntec proposes ISCO using potassium permanganate solution injections <br /> for additional groundwater remediation as a follow-up to SVE pending evaluation of SVE <br /> effects in the area. If needed, the limited ISCO project would use the existing Notice of <br /> Applicability and Monitoring and Reporting Program for the General Waste Discharge <br /> Requirements for in-situ groundwater remediation for ISCO that has been conducted in <br /> other areas of the Site. <br /> K,:m E. LONGLEY SCD, P.E., CHAIR I PATRICK PULUPA, ESO., EXECUTIVE OFFICER <br /> 11020 Sun Center Drive#200. Rancho Cordova,CA 95670 1 www.waterboards.ca.gov/centralvalley <br />