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10 February 2003 <br /> AGE-NC Project No 98-0511 <br /> Page 2 of 4 <br /> I2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> Water samples were collected from each purged well using a new, dedicated disposable plastic <br /> bailer Each water sample was transferred into laboratory-supplied 40-m1 VOA vials containing 0 5 <br /> ml 18% hydrochloric acid as a sample preservative After collection, the samples were properly <br /> labeled,placed in a chilled container,transported under chain-o f-custo dy 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-dibromoethanc(EDB) <br /> and 1,2-di chloroethane (1,2-DCA) in accordance with EPA Method 8260B <br /> I <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 ;eater ranged from 15 59 feet to <br /> 16 45 feet below the tops of the well casings Ground water elevations at the site ranged from <br /> 1 75 feet in MW-7 to 2 13 feet in MW-4 relative to mean sea level The ground water at the site was <br /> inferred to flow generally toward the west-southwest, varying from northwest to southwest, the <br /> gradient was low and varied from approximately 0 002 ft/ft to 0 003 ft/ft (Figure 3) <br /> 3 2 RESULTS OF GROUND WATER SAMPLE ANALYSIS <br /> TPH-g was detected in the ground water samples collected from MW-1, MW-3 and MW-5 at <br /> concentrations of 25,000 micrograms per liter (µg/1), 160 µg/l and 220 µg/1, respectively BTEX <br /> compounds were detected in MW-1 at concentrations of 430µg/l,240 µg/1,950 µg/1 and 4,900 µg/l, <br /> respectively BTEX constituents were not detected in samples collected from MW-2 through MW-8 <br /> 1 <br /> Advanced CeoEnvironmental,Inc <br /> I <br />