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2905 W Benjamin Holt Drive, Stockton, California March 24, 1994 Chevron USA Products Company Page 4 3.3 Soil Sampling During drilling, soil samples were collected at 5-foot Intervals, beginning at approximately 5 feet BGS to the bottom of the boring Samples were collected using a 2 5-inch outside-diameter split-spoon sampler, lined with three 2-inch-diameter by 6-inch-long brass sample tubes The sampler was driven 18 inches ahead of the augers at each sample point Soil samples were field screened for hydrocarbon vapors using a photo-ionization detector (PID) One sample from every 5-foot interval was sealed with aluminum foil, capped, taped, labeled, placed on ice in an insulated container and delivered to Superior Precision Analytical, Inc (Superior), in Martinez, California The field geologist maintained a complete log of the materials encountered during drilling using the Unified Sod Classification System (Appendix B) One of the seven soil samples collected from the boring was selected for analysis The sample was analyzed for benzene, toluene, ethylbenzene and xylenes (BTEX), and total petroleum hydrocarbons-as-gasoline (TPH-G) by Environmental Protection Agency (EPA) methods 5030/8020/modified 8015 34 Groundwater Monitoring Well Installation/Development One monitoring well (MW-8) was installed within the boring drilled on Swenson Park Golf Course (Figure 2) The monitoring well was constructed of 2-inch-diameter, schedule 40 PVC casing with flush threads, and 0 020-inch-slot well screen The well screen was installed from the bottom of the boring (30 feet BGS) up to 10 feet BGS Sand was placed in the well annulus from the bottom of the well to approximately 1 foot above the top of the well screen Bentonite was placed on top of the sand from 9 to 7 feet BGS The well annulus was sealed to approximately 1 foot BGS with a bentonite and neat-cement grout The wellhead is protected at the surface by a locking cap and a traffic-rated street box (with a watertight bolted lid) set in concrete Well construction details are shown in the drill log attached in Appendix B Upon completion, the new monitoring well was developed to remove fine-grained sediments from the well filter pack On January 14, 1994, Groundwater Technology personnel surged and bailed approximately four well volumes of water from MW-8 using a clean PVC bailer Temperature, pH, and conductivity measurements, recorded while purging stabilized after four volumes of groundwater had been removed (Appendix C) Water generated during the development process was pumped to a !�W 38315UM RPr �. i GROUNDWATER TECHNOLOGY