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i Work Plan for Soil and Groundwater Assessment 2 Chevron USA. Products Company, 575 West Grantline Road, Tracy, CA February 14, 1995 TASK 2: SOIL BORINGS/SOIL SAMPLING Groundwater Technology will drill four soil borings at the locations shown on Figure 1 (Attachment 1 ) using a truck-mounted drill rig equipped with 8-inch-diameter hollow-stem augers. The borings will be drilled to approximately 20 feet below ground surface (BGS) to accommodate groundwater monitoring well installation. Soil samples will be collected from each soil boring at 5-foot intervals beginning at 5 feet BGS using a split-spoon sampler lined with 2-inch-diameter by 6-inch-long brass sample tubes. The hollow-stem augers will be steam cleaned before drilling, and sampling equipment will be cleaned between each sampling interval . Each soil sample will be screened for hydrocarbon vapors using a photoionization detector (PID) . Soils encountered during drilling will be logged using the Unified Soil Classification System by a Groundwater Technology field geologist, working under the supervision of a California registered geologist. One sample tube from each sampling interval will be sealed with aluminum foil, capped, taped, labeled, and placed on ice in an insulated container. Based on field observations, selected soil samples from each borehole will be analyzed by a State-certified analytical laboratory for benzene, toluene, ethylbenzene and xylenes (BTEX) , and total petroleum hydrocarbons-as-gasoline (TPH-G) . All soil generated through drilling will be placed on and covered with plastic sheeting on site pending characterization and disposal. Water generated by steam cleaning will be contained in a steam-clean trailer and temporarily stored on site in Department-of-Transportation (DOT) approved 55-gallon drums. TASK 3: GROUNDWATER MONITORING WELL INSTALLATION/DEVELOPMENT Groundwater monitoring wells will be constructed of 2-inch-diameter blank polyvinylchloride (PVC) casing and 0.020-inch-slot PVC well screen. The well screen will be installed approximately 5 to ten feet above and ten feet below the water table. A sand filter pack will be placed within the annulus of each well from the bottom of the boring to approximately 2 feet above the top of the well screen. The annulus will be sealed with approximately 2 feet of bentonite on top of the sand , and a portland cement/bentonite grout to the surface. Well construction specifications will be adjusted according to field conditions, if required . The well heads will be protected by a locking cap and a traffic-rated , watertight street box set in concrete. Prior to groundwater monitoring and sampling, the monitoring wells will be developed by surging and bailing to remove fines from the well and sand pack. The wells will be developed until well water is visibly clear. Development water will be stored in a DOT-approved purge water trailer and hauled to a Chevron refinery for recycling. 013e5GA.WKP EDW GROUNDWATER LITE] TECHNOLOGY .