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28 May 2003 AGE-NC Project No 95-0184 IPage 2 of 5 22 COLLECTION OF GROUND WATER SAMPLES Water samples were collected from MW-1 through MW-4 with a hose bailer while dedicated disposable plastic bailers were used to sample the remaining wells after allowing the wells to achieve a minimum 80% recovery of the pre-purge water volume Each water sample was transferred into laboratory-supplied 40-m1 VOA vials containing 0 5 ml 18% hydrochloric acid as a sample I preservative, the sample from MW-4 was also transferred into a 1-liter amber bottle without preservative After collection, the samples were properly labeled, placed in a chilled container and transported under chain-of-custody to Cal Tech Environmental Laboratories (CTEL), a California Department of Health Services(DHS)-certified analytical laboratory for analysis The samples were analyzed for Y I • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA Method 8015M, • Volatile organic compounds (VOCs), including benzene, toluene, ethylbenzene and total rxylenes (BTEX) with fuel oxygenates, including di-isopropyl ether (DIPE), ethyl tertiary- butyl ether(ETBE),methyl tert butyl ether(MTBE),ternary-amyl methyl ether(TAME)and '. tertiary butyl alcohol (TBA) in accordance with EPA method 826013 Full Scan In addition, ground water sample MW-4 was analyzed for diesel (TPH-d) In accordance with EPA IMethod 8015M ' 3.0. FINDINGS Ground water elevation and flow direction were inferred from field data Hydrocarbon-impact to ' ground water was quantified by laboratory analysis of the 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 elevations (Table 1) Depths to ground water ranged from 34 68 feet to 35 28 feet below the tops of the well casings The ground water levels are as high as approximately ' 20 feet above the screened intervals of MW-1 through MW-4 Ground water elevations at the site ranged from 22 03 feet (MW-3) to 22 54 feet (VW-5C) below mean sea level (MSL) ' The ground water appears to flow generally northeast across much of the site at a hydraulic gradient of approximately 0 003 ft/ft(Figure 2), however, in the northwestern portion of the site the inferred ground water gradient was 0 006 ft/ft i Advanced CeoEnvironmental,Inc ' �r