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1 <br /> I11 November 2002 <br /> • AGE-NC Project No 98-0511 <br />' Page 2 of 4 <br /> Following purging,the depth to ground water was measured to ensure that a minimum of 80%well- <br /> volume recharge had been achieved prior to sampling MW-1 was sampled prior to 80% well- <br /> volume recharge <br />' 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Water samples were collected from each purged well using new disposable plastic bailers Each <br />' water sample was transferred Into laboratory-supplied 40-m1 VOA vials containing 0 5 ml 18% <br /> hydrochloric acid as a sample preservative After collection, the samples were properly labeled, <br /> placed in a chilled container, transported under chain-of-custody to Cal Tech Environmental <br />' Laboratories, a California Department of Health Services (DHS)-certified laboratory, and were <br /> analyzed for <br />' • Total petroleum hydrocarbons quantified as gasoline (TPH-g) In accordance with EPA <br /> Method 5030/8015M, <br />' • Benzene, toluene, ethylbenzene and total xylenes (BTEX) and fuel additives, Including <br /> methyl tertiary-butyl ether(MTBE),tertiary butanol(TBA),di-isopropyl ether(DIPE),ethyl <br /> tertiary-butyl ether(ETBE),tertiary-amyl methyl ether(TAME), 1,2-dlbromoethane(EDB) <br />' and 1,2-dlchloroethane (1,2-DCA) In accordance with EPA Method 8260B <br />' 3.0. FINDINGS <br />' Ground water elevation and flow direction were determined from field data Hydrocarbon-Impact <br /> to ground water was Inferred from laboratory analysis of ground water samples <br />' 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br />' The elevation of ground water In each well was calculated by subtracting the depth to ground water <br /> from the surveyed casing elevation (Table 1) Depths to ground water ranged from 17 35 feet to <br /> 18 27 feet below the tops of the well casings Ground water elevations at the site ranged from <br /> 0 06 feet In MW-5 to 0 27 feet In MW-4 relative to mean sea level The ground water at the site was <br /> Inferred to flow generally toward the west, varying from northwest to southwest, the gradient was <br /> low and vaned from approximately 0 001 ft/ft to 0 002 ft/ft (Figure 3) <br /> i <br />' Advanced GeoEnviron mental,Inc <br /> 1 <br />