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Ms. Vera Fischer <br /> Page 2 <br /> Field Work <br /> Field work was conducted on July 1,2024,by C-57 licensed TEG Northern California(TEG), <br /> under the supervision of a Ground Zero Professional Geologist. <br /> Soil Sampling <br /> At the locations of soil vapor probes VP-1 and VP-2, twinned direct-push borings were <br /> advanced and soil samples collected at the depths of 3 feet and 5 feet. At boring location <br /> 24-SB-1 samples were collected at 5 and 10 feet. The samples were collected in acetate <br /> tubes which were immediately capped, labeled and placed in a chilled ice chest pending <br /> submittal to the laboratory. <br /> Soil Vapor Sampling <br /> Temporary soil vapor sampling probes VP-1 and VP-2 were installed in general accordance <br /> with the DTSC and RWQCB guidelines set forth in the California Environmental <br /> Protection Agency's Advisory —Active Soil Gas Investigations (DTSC and RWQCB, July <br /> 2015). <br /> TEG advanced direct-push sample rods to a depth of five feet. The rods were equipped <br /> with an expendable drive point which was then attached to post-run tubing (PRT). <br /> Prior to purging and sampling, the probes were allowed to sit for a minimum of two hours <br /> to equilibrate. Shut-in tests were then performed to ensure that no leaks were present in the <br /> sample train. The wells were then purged of three tubing volumes and sampled using 1- <br /> liter Summa canisters at a flow rate of 200 ml/minute and at negligible vacuum. <br /> During the collection of each soil vapor sample a leak detection test was conducted to <br /> ensure that there was no intrusion of ambient air into each respective vapor sample. During <br /> the collection of each vapor sample 1,1-difluoroethane (DFA) was applied with a saturated <br /> cloth placed under a shroud around the rod/surface interface and associated connections. <br /> Following the completion of sample collection, the borings were destroyed by retrieving <br /> the drive rods and filling the borings with neat cement under the observation of an SJEHD <br /> inspector. Field notes are included in Attachment B. <br /> Laboratory Analysis <br /> Soil Samples <br /> The soil samples were submitted under chain-of-custody protocol to the Pace Analytical <br /> laboratory in Bakersfield, California (ELAP #1186) and analyzed for total petroleum <br /> hgydrocarbons as gasoline (TPHg) and as diesel (TPHd) by EPA Method 8015 and for <br /> benzene, toluene, ethylbenzene, xylenes (BTEX), fuel oxygenates, lead scavengers and <br /> naphthalene by EPA Method 8260B. <br /> Soil Vapor Assessment Report <br />