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PHASE II ESA WORK PLAN <br />2731 E. MYRTLE STREET <br />STOCKTON, CALIFORNIA <br />2.4 SOIL GAS SAMPLING <br />)MEST <br />EmirownwW Seices & iirtmlogy <br />Following soil sample collection, the borings will be advanced to the target depth for <br />construction of temporary vapor wells for the collection of soil gas samples (Figure 2-1). The <br />temporary vapor wells will be constructed within the borehole annulus following WEST'S SOPS <br />and CaIEPA's Advisory -Active Soil Gas Investigations. The soil gas samples, following an <br />approximate two-hour timeframe for the surrounding formation to equilibrate, will then be <br />collected into 1 -liter stainless steel laboratory -supplied and individually certified Summa <br />canisters outfitted with a flow control valve manifold. Field data forms will be maintained to <br />record purging and shut-in testing parameters prior to soil gas sample collection (Appendix B). <br />Following the soil gas sample collection, the Summa canisters will be transported to a SWRCB <br />ELAP certified laboratory for chemical analysis following ASTM D 4840 chain -of -custody <br />protocols. The soil gas samples will be analyzed for VOCs by USEPA Method TO -15 SIM and <br />helium tracer gas by ASTM D 1946. The target soil gas sample depths and suite of analytes are <br />presented in Table 2-1. <br />2.5 BORING DESTRUCTION <br />Following completion of soil and soil gas sampling, the temporary vapor wells will be <br />overdrilled to remove the vapor well materials (e.g., tubing, sand filter and bentonite) and the <br />borehole annulus grouted to the surface using a Portland Type II Cement/bentonite mixture in <br />accordance with the SJCEHD boring permit requirements. The top of the boreholes will be <br />completed to match the existing ground surface. <br />2.6 INVESTIGATION -DERIVED WASTES <br />Investigation -derived wastes including vapor well materials and soil cuttings will be placed in <br />United States Department of Transportation -approved containers and removed from the Site at <br />the completion of the drilling and sampling activities. The containers will be temporarily stored <br />5 <br />9123 <br />