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ATTACHMENT B <br /> FIELD AND LABORATORY PROCEDURES <br /> Geoprobe Procedures <br /> The Geoprobe borings will be advanced using a direct-push, hydraulic and percussion <br /> drive-point sampling system This will involve the driving of a one-inch O D screen point <br /> sampler to deep groundwater(expected to be approximately 70 feet bgs) Soil samples will <br /> be collected every 5 feet Once to depth, the sampler case will be retracted a distance <br /> corresponding to the length of an enclosed 1/2 inch x 18 inch stainless steel screen This <br /> disengages an expendable point and allows the slotted screen to extend into the open <br /> borehole The water is then allowed to enter the sampler through the screen for collection <br /> Groundwater will be collected from the boring using a mini-bailer, lowered to the screened <br /> interval through the hollow drive tube The collected water samples will be submitted to a <br /> California State-certified laboratory for analysis <br /> Organic Vapor Procedures <br /> Soil samples collected at 5-foot depth intervals during drilling will be analyzed in the field <br /> for ionizable organic compounds using a flame-ionization detector (FID) or a photo- <br /> ionization detector(PID) with a 10 2 eV lamp The test procedure will involve measuring <br /> approximately 30 grams from an undisturbed soil sample, placing this subsample in a <br /> ZiplockTm-type bag or in a clean glass far, and sealing the far with aluminum foil secured <br /> under a ring-type threaded lid The container will be warmed for approximately <br /> 20 minutes (in the sun), then the head-space within the container will be tested for total <br /> organic vapor, measured in parts per million as benzene (ppm, volume/volume) The <br /> instrument will be calibrated prior to drilling The results of the field testing will be noted <br /> on the boring logs FID/PID readings are useful for indicating relative levels of <br /> contamination, but cannot be used to evaluate hydrocarbon levels with the confidence of <br /> laboratory analyses <br /> Laboratory Procedures <br /> Selected soil samples will be analyzed for the presence of total petroleum hydrocarbons <br /> calculated as gasoline (TPH-g), benzene, toluene, ethylbenzene, xylenes (BTEX) and <br /> methyl tertiary-butyl ether (MtBE) using EPA Methods 8015 Modified and 8020, with <br /> MtBE confirmation of the highest detected MtBE concentration from each boring using <br /> NlrancfpllProJectslProJects1911101111A101021Workplan2 doe B-1 <br />