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.r r Work Plan for Site Assessment <br /> Former Texaco Service Station <br /> Chevron Site ID 309075 <br /> �+ September 30, 2009 <br /> 3.4 QUALITY ASSURANCE/QUALITY CONTROL PLAN <br /> Quality assurance/quality control (QA/QC) samples will be submitted for laboratory analysis. A <br /> laboratory supplied trip blank will accompany each groundwater sample delivery group. Trip <br /> blank samples will be analyzed for TPH-GRO, BTEX and MTBE. For every twenty soil samples <br /> obtained, a duplicate soil sample will be collected and analyzed for the same constituents as <br /> �., described in Section 3.5.1. <br /> 3.5 SOIL BORINGS <br /> Prior to drilling, the two borings will be hand cleared using an air knife or hand auger to a <br /> minimum depth of 8 feet 1 inch (utility clearance depth) below ground surface (bgs). The two <br /> borings, one shallow and one deep, will be advanced using hollow stem augers to <br /> approximately 75 feet and 120 feet bgs, respectively. <br /> 3.5.1 Soil Sampling and Screening <br /> Soil samples for logging purposes will be collected continuously for visual classification from 8 <br /> feet 1 inch bgs to the total borehole depth using a California-modified split-spoon sampler, core <br /> barrel sampler, or similar sampling device. Soil samples will be field screened with a photo- <br /> ionization detector (PID). The soil screening procedures will involve measuring approximately <br /> 30 grams from a relatively undisturbed soil sample and placing this sample in a sealed container <br /> (zip-lock bag). The bag will be warmed in the sun for approximately 20 minutes, then the head <br /> space within the bag will be tested for total organic vapor, measured in parts per million. The <br /> lo„ PID results will be recorded on the field boring logs. Although PID measurements are useful for <br /> indicating relative levels of impact, the measurements cannot be used to evaluate hydrocarbon <br /> levels with the confidence of laboratory results. <br /> w <br /> Up to twelve soil samples will be collected from the deep boring at approximate 10-foot intervals <br /> and will be submitted to a laboratory for analysis based on PID measurements and/or visual <br /> bw characteristics (i.e. staining, odors, sheen). The select soil samples, and applicable duplicate <br /> samples, will be retained in brass, stainless steel, or plastic liners, capped with Teflon squares <br /> and plastic end caps, and sealed in zip-lock bags. The samples will be placed on ice, cooled to <br /> �. approximately 4 degrees centigrade, and transported to a State of California certified laboratory <br /> under chain-of-custody documentation. The soil samples will be analyzed for the following <br /> constituents: <br /> V <br /> • Total petroleum hydrocarbons in the gasoline range [TPH-GRO (C6-C10)] by United <br /> States Environmental Protection Agency(USEPA) Method 8260B <br /> • Total petroleum hydrocarbons in the diesel range [TPH-DRO (C10-C28)], total petroleum <br /> hydrocarbons as motor oil (TPH-MO) [C16—C36], and methanol by USEPA Method 8015B <br /> low <br /> • Benzene, toluene, ethylbenzene, and total xylenes (BTEX) by USEPA Method 8260B <br /> bw <br /> GAENV\CHEVR0N\309075\6 Deliverables\Work Plan\Downgradient Wells\Work Plan for Downgradient Wells_379910950.doc 3 <br /> V <br />