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06 September 2005 <br /> • 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 wells MW-1 through MW-4, MW-7, VW-3, and VW-4 with a <br />' hose 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) benzene, toluene, ethylbenzene, and total xylenes <br /> (BTEX) and fuel oxygenates di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), <br /> methyl tertiary-butyl ether (MTBE), tertiary-amyl methyl ether (TAME), tertiary-butyl <br />' . alcohol(TBA), 1,2-dibromoethane(EDB),and 1,2-dichloroethane(1,2-DCA)in accordance <br /> 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 /> 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 elevation (Table 1) Due to the angle of boring of VW-5, special <br /> calculations are required to compute the ground water elevation (Appendix C) Depths to ground <br /> water ranged from 36 00 feet to 36 72 feet below the tops of the well casings The average ground <br /> water elevation at the site was 23 56 feet below mean sea level(MSL), indicating a increase of 149 <br /> feet below MSL between the fourth quarter 2004 and first quarter 2005 monitoring events The <br /> . ground water levels were as high as approximately 19 feet above the screened intervals in wells <br /> Advanced GeoEnvironmentai,Inc <br /> 1 <br />