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{i <br /> ATTACHMENT A <br /> FIELD AND LABORATORY PROCEDURES <br /> Geoprobe Procedures <br /> The Geoprobe borings were advanced using a direct-push, hydraulic and percussion drive- <br /> point sampling system. Soil samples were collected every 5 feet. Once to depth, the <br /> sampler case was retracted a distance corresponding to the length of an enclosed 112 inch x <br /> 12 inch stainless steel screen. This disengages an expendable point and allows the slotted <br /> screen to extend into the open borehole. The water is then allowed to enter the sampler <br /> through the screen for collection. <br /> Groundwater was collected from the boring using a mini-bailer, lowered to the screened <br /> interval through the hollow drive tube. The collected water samples were submitted to a <br /> California State-certified laboratory for analysis. <br /> Organic Vapor Procedures <br /> g P <br /> Soil samples collected at 5-foot depth intervals during drilling was analyzed in the field for <br /> ionizable organic compounds using a photo-ionization detector (PID) with a 10.2 eV lamp. <br /> The test procedure involves measuring approximately 30 grams from an undisturbed soil <br /> sample, placing this subsample in a Ziplock'"-type bag. The container was warmed for <br /> approximately 20 minutes (in the sun), then the head-space within the container is tested <br /> for total organic vapor, measured in parts per million as benzene (ppm; volume/volume). <br /> The instrument was calibrated prior to drilling. The results of the field testing was noted <br /> on the boring logs. PID readings are useful for indicating relative levels of contamination, <br /> but cannot be used to evaluate hydrocarbon levels with the confidence of laboratory <br /> analyses. <br /> Laboratory Procedures <br /> Selected soil samples were 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 /> EPA Method 8260. Groundwater samples was analyzed for the presence of TPH-g, BTEX, <br /> . and MtBE using EPA Methods 8015 Modified, 8020. If MtBE is reported it was <br /> confirmed by EPA Method 8260. <br /> N:lrancfpllProjects\Projects\911101111A\0102\911011rpt.doc A-1 <br />