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0 0 <br />ATTACHMENT A <br />FIELD AND LABORATORY PROCEDURES <br />Exploratory Sampling <br />Two soil borings will be drilled using a Simul-Probe , Enviro-Coreg' or similar driven probe <br />technology to collect discrete soil and discrete groundwater samples. All down -hole <br />equipment will be steam cleaned prior to drilling. Representative undisturbed soil samples <br />will be collected from the boring for geologic logging, field hydrocarbon vapor screening and <br />laboratory analysis. Soil samples will be logged by a PACIFIC geologist using the Unified <br />Soil Classification System. The borings will be drilled to a total depth of approximately <br />90 feet below ground surface (bgs). <br />Continuous core sampling will be conducted in the boring proposed to be located adjacent to <br />the USTs. Soil samples will be collected from the proposed boring to be located east of the <br />product islands at 5 -foot depth intervals. At each sampling interval, the middle sample liner <br />will be retained for chemical analysis. The ends of the liner will be sealed with Teflon® tape <br />and plastic end caps, and placed in a chilled container for delivery to a state -certified <br />analytical laboratory along with appropriate chain -of -custody documentation. <br />Organic Vapor Procedures <br />Soil samples collected at each interval will be field screened for VOCs using headspace <br />analysis and a photo -ionization detector (PID) or flame ionization detector (FID). The test <br />procedure involves measuring approximately 30 grams from an undisturbed soil sample, and <br />placing this subsample in a ziplock type bag. After the soil is allowed to equilibrate for <br />approximately 20 minutes, the probe tip of the PID or FID is inserted into the bag. The <br />highest measured concentrations of VOCs within the headspace of the bag will be recorded <br />on the boring log (Attachment B). PID and FID readings are useful for indicating relative <br />levels of contamination, but cannot be used to evaluate hydrocarbon levels with the <br />confidence of laboratory analyses. <br />920-124.IA/WPLAN.DOC A-1 December 8, 1997 <br />