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E <br />Cf LI►ORNI• <br />Water Boards <br />Central Valley Regional Water Quality Control Board <br />16 November 2017 <br />Dana Perry <br />Reynolds and Brown <br />1200 Concord Ave, Suite 200 <br />Concord, CA 94520 <br />EDMUND Q. BROWN JR. <br />` GOVERNOR <br />MATTHEW RODRIOUEZ <br />SEC STA" FOR <br />ENVIRONMENTAL PROTECTIOI. <br />CONDITIONAL APPROVAL OF CONFIRMATION SITE INVESTIGATION WORK <br />PLAN FOR 17100 MURPHY PARKWAY, FORMER PILKINGTON NORTH <br />AMERICA INC, 500 EAST LOUSE AVENUE, LATHROP, SAN JOAQUIN <br />COUNTY <br />Staff of the Central Valley Regional Water Quality Control Board (Regional Water Board) have <br />reviewed the 19 October 2017 Confirmation Site Investigation Work Plan (Work Plan) for 17100 <br />Murphy Parkway, Lathrop, San Joaquin County (Site), submitted on your behalf by Advanced <br />Geo Environmental (AGE). The Work Plan was submitted as requested by the Regional Water <br />Board in its 26 September 2017 Comments on Draft Request for Clean Closure and Proposed <br />Post -Closure Land Use Plan for 17100 Murphy Parkway letter. The Work Plan was requested <br />to implement confirmation sampling methods to adequately define the limits of the North and <br />South Waste Cell excavations, investigate potential subsurface. soil contamination beneath the <br />former waste cells, and define the vertical and horizontal extent of buried waste on the property <br />up to the western property line with 171200 Murphy Parkway, Lathrop. <br />The Work Plan details confirmation sampling that includes six total borings with analysis of nine <br />soil samples total from the North and South Waste Cells. The boring depths are anticipated to <br />reach below the imported fill at 18 -feet below ground surface (ft-bgs) in the North Waste Cell <br />and 15-ft-bgs in the South Waste Cell. Proposed sampling analyses for constituents of concern <br />include: dioxin/furans (EPA 1613 and SW 8290), total petroleum hydrocarbons (8015), volatile <br />organic compounds (8260B), polychlorinated biphenyls (8082), semi -volatile organics and <br />polynuclear aromatics (8270), and Cam 17 metals TTLC (6010B, 6020, 207, 208). One soil <br />sample is proposed for analysis using the full suite of contaminants of concern, and the <br />remaining eight soil samples are anticipated for dioxin/furan analysis. <br />Regional Water Board staff concur with the Work Plan proposal on the following conditions: <br />Regional Water Board staff recommend collecting confirmation samples using a grid <br />pattern on the floor of each waste cell immediately below the imported fill to <br />systematically collect 1 -sample from each 20 -ft by 20 -ft unit/area or approximately 1. <br />sample every 400-ft2 to provide adequate sampling density to evaluate the removal of <br />KARL E. LONOLEY SCD, P.E., CHAIR I PAMELA C, CREEDON P.E., BCEE, EXECUTIVE OFFICER <br />11020 Sun Center Drive #200, Rancho Cordova, CA 45670 1 www.waterboards.ca.gov/centralvalley <br />NQOYCIGY PAYGR <br />