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2 . 1 Sgil Borings and Eamplina <br /> On December 27, 1991, Alton Geoscience supervised the onsite <br /> drilling of 10 exploratory soil borings . All drilling <br /> activities were performed by West Hazmat Drilling Corporation <br /> of Rancho Cordova, California using a truck--mounted CME-55 <br /> drilling rig. All soil borings were drilled using <br /> 4-inch-diameter hollow--stem augers to depths ranging from <br /> 11 to 20 . 5 feet below grade. Borings B-1 and B-2 were drilled <br /> ad3acent to the existing underground waste oil tank; Borings <br /> B--3, B-4 , B--S, and B-6 were drilled proximal to the dispenser <br /> islands and associated piping; and Barings B-6 , B-7 , B-8, B-9 <br /> and B-10 were drilled adjacent to the underground fuel <br /> storage tanks . The depth of the soil borings did not exceed <br /> 20 feet below grade due to ground water being encountered at <br /> that depth. All borings were backfilled to grade with batch <br /> mixed 9--sack cement/sand slurry. The locations of the soil <br /> borings are shown in Figure 1 . <br /> Boring logs were generated using the Unified Soil <br /> Classification System including a description of soil <br /> characteristics such as color, moisture, consistency, and <br /> field readings using an organic vapor meter (OVM) . The <br /> boring logs are included as Appendix B. <br /> 2 .2 Laboratory Ana sus <br /> All laboratory analyses of soil samples were performed by a <br /> California-certified analytical laboratory, using standard <br /> test methods of the U.S. Environmental Protection Agency <br /> (EPA) and the California Department of Health Services (DHS ) . <br /> PACE, Inc. of Novato, California analyzed the soil samples . <br /> Selected soil samples from Borings B-1 through B-10 were <br /> analyzed for the following constituents : <br /> e Total petroleum hydrocarbons as gasoline (TPH-G) <br /> using EPA Methods 5030/8015 <br /> • Benzene, toluene, ethylbenzene, and total xylenes <br /> (BTEX) constituents using EPA Methods 5030/8020 <br /> Selected soil samples from Borings B-1 and B-2 were analyzed <br /> for total oil and grease (TOG) using EPA Method SM 5520. The <br /> soil sample collected from Boring B-7 from a depth of 10 feet <br /> below grade was also analyzed for organic lead, using <br /> California Department of Health Services Method No. 338, to <br /> investigate the presence of that constituent in a soil sample <br /> with elevated concentrations of TPH--G and BTEX constituents . <br /> 2 <br />