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08 April 2014 AGE Project No. 07-1537 Page 4 of 6 Soil samples will be collected at discreet five-foot intervals using a 1.45-inch Geoprobe soil sampling assembly loaded with a 2-foot acetate liner. Upon sample retrieval, a selected portion of the acetate liner will be separated and the ends of the liner will be covered with Teflon sheets, capped and sealed with tape. Appropriately sealed and labeled samples will be placed in a chilled container under ice and transported under chain-of-custody procedure to a CDPH-certified laboratory for analysis of the chemical constituents in Section 3.4. Each sample sleeve will be labeled with the boring designation, depth, time, date and sampler's initials. Soils encountered in the borings will be visually classified by an AGE geologist in accordance with the Unified Soil Classification System (USCS). Additionally, soil samples will be field- screened for the presence of volatile organic compounds using an organic vapor meter (OVM), equipped with photo-ionization detector (PID). 3.2. SOIL-VAPOR WELL INSTALLATION A total of nine, four-inch pilot soil borings will be completed as soil-vapor wells utilizing '/4-inch diameter teflon tubing and a six-inch soil vapor tip installed to 5 feet bsg. The tubing will be attached to the vapor tip, which will be set to a depth of 4.5 to 5 feet bsg. Once the tip is set a filter pack material consisting of pre-washed #2/12 Lonestar sand will be added from total depth to approximately 4 feet bsg. A dry bentonite seal will be placed above the filter pack to a depth of 3 to 4 feet bsg and pre-hydrated bentonite will be placed above the dry bentonite from 3 feet bsg to near surface. The bentonite will be allowed to hydrate for a minimum of one half hour prior to installing a flush mounted well box over the wells. Approximately, 3 feet of extra tubing will be run above ground for soil-vapor sample collection. A well construction diagram illustrating the proposed design is included as Figure 3. 3.3. SOIL-VAPOR SAMPLE COLLECTION Soil-vapor samples will be collected after allowing a minimum of 48 hours following installation of the soil-vapor wells. Vapor wells will each be purged for approximately 10.3 minutes (equal to three purge volumes at 3.4 minutes per volume; Appendix C) utilizing a 6-liter purge canister and manifold, calibrated to 200 milliliters per minute (ml/min). An estimated volume of approximately 2.05 liters will be purged from each vapor well prior to sampling. One-liter Summa® sampling and six-liter Summa® purge canisters will be used to collect soil-vapor samples for TO-15 analysis. Sampling and purge canisters will be connected together with a dedicated and serialized sampling inlet manifold. The sampling inlet manifold consists of a vapor-tight valve; a particulate filter; a flow restrictor calibrated to 200 milliliters per minute (ml/min); a stainless steel tee-fitting; two Advanced GeoEnviron mental Inc.