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Sampling and Analysis Plan for Phase II Environmental Site Assessment 125 North Stockton Street, Lodi,CA 95240 Collected samples will be placed into laboratory-supplied containers for shipment to the analytical laboratory. Following completion of sampling activities, the boreholes will be backfilled with neat cement grout or hydrated bentonite in accordance with permit requirements and patched with like materials to match existing grade. 3.2.2 Soil Vapor Sampling Four temporary soil borings will be extended to approximately 15.5 feet bgs using direct-push equipment and installed with dual-nested temporary soil vapor probes. Each soil vapor probe will consist of a stainless-steel inlet fitting connected to Nylaflow® tubing. The inlet fitting will be installed at approximately 5 and 15 feet bgs within one foot of bedding sand. The overlying annular space will be filled with approximately six inches of dry, granular bentonite, and the remaining annular space will be filled with granular bentonite and hydrated in six-inch lifts. Soil vapor probes will be allowed to equilibrate for a minimum of 48 hours before sampling, in accordance with DTSC guidance. Samples will be collected into laboratory-supplied Summa canisters with dedicated flow controllers set at approximately 175 milliliters per minute. Prior to sampling, the sample collection "train" will be tested for tightness by isolating the canister and flow controller fittings and applying a vacuum of 7.5 inches mercury using a three-way valve and syringe.The shut-in test will be considered complete if the apparatus is able to hold vacuum for a period of at least one minute. If leaks are observed, the fittings will be tightened and re-tested. Prior to sampling, the soil vapor probe will be purged of three volumes of air, corresponding to the calculated volume of air within the tubing and the pore space of the bedding sand. During sampling, the sampling apparatus will be placed beneath a sampling shroud, and helium gas applied as a leak check compound at a concentration of approximately 30 percent by volume, as determined using a helium detection meter.Sampling will continue until the vacuum gauge on the Summa canister registers approximately 5 inches mercury. Summa canisters will be labeled and transported to the analytical laboratory for analysis. Following completion of sampling activities, the temporary probes will be removed, and the surface patched with like materials to match existing grade where sampling is conducted in areas of existing pavement. 3.2.3 Sample Handling and Analysis Soil and soil vapor samples will be transported to Pace National laboratory under chain-of-custody protocol for chemical analysis. Consistent with the QAPP, sample designations will incorporate three components as summarized below: Location Code Sample Type Depth Interval Example 131, 132, 133, 134 Soil 0.5-1 ft, 3 ft, 5 ft B 1-S-1, B 1-S-3 131, B4, B6, B10 Soil vapor 5 ft, 15 ft B1-SV-5, B1-SV-15 Stantec 11