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Additional Soil Vapor Assessment Work Plan Page 7 <br /> CPSA,Lodi,California <br /> March 22,2024 <br /> Soil and Soil Vapor Sampling <br /> A total of ten(10)soil samples will be collected from borings SV3 and SV4 using the Terra Core® <br /> sampling tool/method as described in United States Environmental Protection Agency(USEPA) <br /> SW-846 Method 5035. Soil samples will be collected from the acetate liners for each boring at <br /> depths of 5, 10, 15, 25, and 40 ft-bgs. The collected soil samples will be labeled, placed on ice, <br /> and handled under standard chain-of- custody procedures for delivery to Eurofins,a California- <br /> certified laboratory and analyzed for VOCs using EPA Method 5035/8260B . <br /> The ten (10) soil vapor samples will be collected in accordance with the sampling protocols <br /> established in the Advisory (DTSC, 2012). Soil vapor samples will be collected in individual <br /> certified 1-liter SUMMA® canister where the SUMMA® canister will supply the vacuum to draw <br /> soil vapor into the canister for analysis. The TSV probes will be purged and sampled in accordance <br /> with Section 4 (Soil Gas Sample Collection) and leak detection will be performed in accordance <br /> with Section 4.2.2.1 (Leak Check Compounds [Liquid]) of the Advisory. CHT proposes to use <br /> helium as the leak detection compound. <br /> Following soil vapor sample collection, a photoionization detector(PID) will be connected to the <br /> polyethylene soil vapor probe tubing to obtain a preliminary field value for the sample collection <br /> location. Measurements of vacuums, purging and equilibration time intervals, and PID readings <br /> will be recorded on Soil Vapor Sampling Data Sheets. The SUMMA®canister soil vapor samples <br /> will be delivered under chain-of-custody (COC) protocols to AirToxics, a California-certified <br /> laboratory for testing by EPA method TO-15 analysis for chlorinated VOCs. Additionally, the <br /> leak detection compound(helium)will be analyzed using Modified ASTM Method D-1946. <br /> Upon completion of sampling activities, the TSV probes will be abandoned by removing <br /> temporary well points and sealing the borehole with a neat cement grout or by using the appropriate <br /> method approved by SJDEH, and under the supervision of an SJDEH inspector. <br /> SUB-SLAB SAMPLING <br /> In order to further delineate the extent of the PCE plume in soil vapor beneath the 212 W. Pine St. <br /> building, one (1) semi-permanent sub-slab soil gas Vapor Pin® (or equivalent) will be installed in <br /> Tenant Space 3 (SS-6 shown on Figure 4) below the concrete slab of the building in a manner <br /> consistent with DTSC guidance. Standard Operating Procedures for Installation and Use of the <br /> Vapor Pins, which were obtained from the manufacturer/distributor of the devices, are provided <br /> in Attachment A. <br /> Methodology <br /> At the proposed location, a temporary sub-slab soil Vapor Piny"' will be installed using the <br /> following procedures— <br /> • A 5/8-inch diameter hole will drilled through the concrete slab and 1-inch into the <br /> underlying material to form a void; <br /> 581 MONTEGO TERRACE,SUNNYVALE,CA 94089 TEL:415-424-3009 <br />