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Work Plan for Soil and Groundwater Assessment 2 <br /> Chevron U.S.A. Products Company,508 Charter Way, Stockton, CA November 11, 1994 <br /> TASK 2: SOIL BORINGS/SOIL SAMPLING <br /> Groundwater Technology will drill four borings at the locations shown on Figure 2 (Attachment 1) <br /> using a truck-mounted drill rig equipped with 8-inch-diameter hollow-stem augers. One of the soil <br /> borings will be drilled to approximately 45 feet below ground surface (BGS) and backfilled with a <br /> cement/bentonite grout. Three of the borings will be drilled to approximately 55 feet BGS to <br /> accommodate groundwater monitoring well installation. <br /> Soil samples will be collected from each soil boring at 5-foot intervals beginning at 5 feet BGS using <br /> a split-spoon sampler lined with 2-inch-diameter by 6-inch-long brass sample tubes. The hollow- <br /> stem augers will be steam cleaned before drilling, and sampling equipment will be cleaned between <br /> each sampling interval. Each soil sample will be screened for hydrocarbon vapors using a <br /> photoionization detector (PID). Soils encountered during drilling will be logged using the Unified Soil <br /> Classification System by a Groundwater Technology field geologist, working under the supervision of <br /> a California registered geologist. One sample tube from each sampling interval will be sealed with <br /> teflon sheets, capped, taped, labeled, and placed on ice in an insulated container. Based on field <br /> observations, selected soil samples from each borehole will be analyzed by a State-certified <br /> analytical laboratory for benzene, toluene, ethylbenzene and xylenes (BTEX), and total petroleum <br /> hydrocarbons-as-gasoline (TPH-G). In addition to the above analyses, the boring drilled nearest the <br /> used-oil tank will be analyzed for total petroleum hydrocarbons-as-diesel (fPH-D) by EPA 3510\8015 <br /> modified, oil and grease by EPA method 418.1, halogentated volatile organic compounds (HVOCs) <br /> by EPA method 8010, semi-volatile organic compounds (SVOCs) by EPA method 8270 and the <br /> LUFT metals (Cd, Cr, Pb, Ni, and Zn) by EPA 7000 series methods. <br /> All soil generated through drilling will be placed on and covered with plastic sheeting on site pending <br /> characterization and disposal. Water generated by steam cleaning will be contained in a steam- <br /> clean trailer and temporarily stored on site in Department-of-Transportation (DOT) approved 55- <br /> gallon drums. <br /> TASK 3: GROUNDWATER MONITORING WELL INSTALLATION/DEVELOPMENT <br /> Groundwater monitoring wells will be constructed of 2-inch-diameter blank polyvinylchloride (PVC) <br /> casing and 0.020-inch-slot PVC well screen. The well screen will be installed approximately 10 feet <br /> above and ten feet below the water table. A sand filter pack will be placed within the annulus of <br /> each well from the bottom of the boring to approximately 2 feet above the top of the well screen. <br /> The annulus will be sealed with approximately 2 feet of bentonite on top of the sand, and a portland <br /> cement/bentonite grout to the surface. Well construction specifications will be adjusted according <br /> 00716GA.WKP(CHV-106) <br /> GROUNDWATER <br /> ❑❑❑ TECHNOLOGY <br />