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I 22 July 2002 AGE-NC Project No 98-0511 IPage 2 of 4 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES Water samples were collected from each purged well using new disposable plastic bailers Each water sample was transferred into laboratory-supplied 40-m1 VOA vials containing 0 5 ml 18% I hydrochloric acid as a sample preservative After collection, the samples were properly labeled, placed in a chilled container, transported under chain-of-custody to Cal Tech Environmental Laboratories, a California Department of Health Services (DHS)-certified laboratory, and were analyzed for • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA IMethod 5030/8015M, • Benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary butyl ether I (MTBE) in accordance with EPA method 8021, and • Fuel oxygenates,including MTBE,tertiary butanol(TBA),di-isopropyl ether(DIPE), ethyl tertiary-butyl ether(ETBE),tertiary-amyl methyl ether(TAME), 1,2-dibromoethane(EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B Through an oversight, the samples were not analyzed for ethanol and methanol 3.0. FINDINGS Ground water elevation and flow direction were determined from field data Hydrocarbon-impact to ground water was inferred from laboratory analysis of ground water samples 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION ' The elevation of ground water in each well was calculated by subtracting the depth to ground water from the surveyed casing elevation (Table 1) Depths to ground water ranged from 13 20 feet to 13 97 feet below the tops of the well casings Ground water elevations at the site ranged from ' 4 08 feet in MW-5 to 4 83 feet in MW-2 relative to mean sea level The ground water at the site was inferred to flow generally toward the west, varying from northwest to southwest, the gradient was low and varied from approximately 0 002 ft/ft to 0 007 ft/ft (Figure 3) I 32 RESULTS OF GROUND WATER SAMPLE ANALYSIS ' TPH-g was detected in the ground water samples collected from MW-1 and MW-5 at concentrations of 11,000 micrograms per liter(µg/1)and 1,800µg/1,respectively BTEX compounds were detected Advanced GeoEnvironmental,Inc I