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' 12 November 2004 <br /> i AGE-NC Project No 95-0184 <br />' Page 2 of 5 <br />' 2 2 COLLECTION OF GROUND WATER SAMPLES <br /> Water samples were collected from MW-1 through MW-4, MW-7, VW-3, and VW-4 with a hose <br />' bailer while dedicated disposable plastic bailers were used to sample the remaining wells after <br /> allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume Each water <br /> sample was transferred Into laboratory-supplied 40-milliliter(ml) volatile organic analysis (VOA) <br />' vials containing 0 5 ml 18%hydrochloric acid solution as a sample preservative, the sample from <br /> MW-4 was also transferred Into a 1-liter amber bottle without preservative After collection, the <br /> samples were properly labeled,placed in a chilled container,and transported under chain-of-custody <br />' to Cal Tech Environmental Laboratories (CTEL), a California Department of Health Services <br /> (DHS)-certified analytical laboratory, for analysis The samples were analyzed for <br />' • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 8015M, and <br />' • Volatile organic compounds (VOCs), Including benzene, toluene, ethylbenzene, and total <br /> xylenes (BTEX) and fuel oxygenates dl-Isopropyl'ether (DIPE), ethyl tertiary-butyl ether <br /> (ETBE), methyl tert-butyl ether (MTBE), tertiary-amyl methyl ether (TAME), and tertiary <br />� . butyl alcohol (TBA) in accordance with EPA Method 8260B Full Scan <br />' In addition, the ground water sample from well MW-4 was analyzed for total petroleum <br /> hydrocarbons quantified as diesel (TPH-d) in accordance with EPA Method 8015M <br /> 1 3.0. FINDINGS <br />' Ground water elevation and flow direction were Inferred from field data Hydrocarbon Impact to <br /> ground water was quantified by laboratory analysis of the 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 elevations (Table 1) Depths to ground water ranged from 35 35 feet to <br /> 36 05 feet below the tops of the well casings The average ground water elevation at the site was <br />' 22 90 feet below mean sea level (MSL), indicating an average decrease of 0 12 feet below MSL <br /> between the first and second quarter monitoring events The ground water levels were as high as <br /> approximately 19 feet above the screened Intervals in wells MW-1 through MW-4 and MW-7, <br />' VW-2B, and VW-5C <br /> 1 Advanced GeoEnviron mental,Inc <br /> 1 <br />