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The well and borings will be drilled utilizing a truck-mounted drill rig <br /> equipped with continuous flight, hollow-stem augers Prior to drilling <br />' each well and boring, the augers will be cleaned and decontaminated <br /> Soil samples will be collected during drilling utilizing a modified <br /> California split-spoon sampler equipped with pre-cleaned brass <br /> sampling tubes For each well and boring, the soil samples will be <br /> collected every two feet within the unsaturated zone, as outlined in the <br />' Tri-Regional Board Staff Recommendations for Preliminary <br /> Evaluation and Investigation of Underground Tank Sites (10 August <br /> 1990) The sampler will be cleaned prior to each use in an Alconox© <br /> solution and rinsed with de-ionized water. Soil samples retained in <br /> brass tubes for laboratory analysis will be secured by covering the ends <br /> of the tubes with Teflon® film and plastic caps <br /> Soil samples will be labeled with a unique sample number, the project <br /> name and location, the date and time, and the sampler's initials <br /> I Samples will then be placed in Zip-Lock® type plastic bags, sealed, and <br /> placed in an iced cooler Information noted on the label will be <br /> recorded on a chain-of-custody form After completion of drilling, the <br /> samples will be delivered under chain-of-custody to a California <br /> Department of Toxic Substances Control (DTSC)-certified laboratory <br /> Headspace measurements of organic vapor concentrations will be <br /> obtained on select soil samples using a photoionization detector The <br /> organic vapor concentration will be recorded on the field drilling logs <br /> If headspace measurements indicate significantly elevated levels of <br /> volatile organic vapors, then the need for installing additional borings <br /> and/or wells will be evaluated The borings/wells would be installed <br />' at locations further from the UST excavation to define the lateral limit <br /> of affected soils <br />' Soil samples and drill cuttings will be visually inspected and classified <br /> according to the Unified Soil Classification System (USCS) by a <br /> qualified ERM geologist Boring logs will be constructed to record <br />' vertical variations in lithology, moisture content, color, texture, and <br /> organic vapor concentration of the soil <br />' All soil removed from the boreholes and all rinsate will be stored in <br /> sealed 55-gallon drums pending the results of laboratory analyses Each <br />' drum will be clearly labeled to indicate its contents and boring number <br /> If analytical results indicate that the soil and water contains petroleum <br /> hydrocarbons in excess of regulatory action limits, they will be disposed <br /> of appropriately <br />' 2-2 <br />