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I ' 30 April 2003 ' AGE-NC Project No 95-0184 Page 2 of 5 ' 2 2 COLLECTION OF GROUND WATER SAMPLES Water samples were collected from each monitoring and vapor extraction well using new disposable ' bailers 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 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• • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA ' Method 8015m, • Volatile organic compounds (VOCS), including benzene, toluene, ethylbenzene and total ' xylenes (BTEX) with fuel oxygenates, including di-isopropyl ether (DIPE), ethyl tertiary- butyl ertiarybutyl ether(ETBE),MTBE,tertiary-amyl methyl ether(TAME)and tertiary butanol(TBA) in accordance with EPA method 8260B In addition, ground water sample MW-4 was also analyzed for diesel (TPH-d) in accordance with ' EPA Method 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 35 25 feet to 35 99 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 throu -4 Ground water elevations at the site ' ranged from 22 65 feet(VW-2B) to 23 18 feet (VW-5 below mean sea level (MSL) The groundwater appears to flow generally northward across much of the site at a hydraulicgradient ' of approximately 0 009 ft/ft(Figure 2), however, in the southeastern portion of the site the inferred ground water flow direction was easterly 1 Advanced GcoEnveronmentai,Inc