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13 March 2005 <br /> AGE-NC Project No 96-0263 <br /> Page 2 of 4 <br /> allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume Each water <br /> Isample was transferred into three 40-ml volatile organic analysis(VOA)vials containing 0 5 ml 18% <br /> hydrochloric acid as a sample preservative <br /> After collection, the samples were properly labeled, placed in a chilled container and transported <br /> under chain of custody to Cal Tech Environmental Laboratories (CTEL), a State of California <br /> Department of Health Services (DHS)-certified analytical laboratory The samples were analyzed <br /> for <br /> • Total petroleum hydrocarbons quantified as gasoline (TPI -g) in accordance with EPA <br /> Method 5030/8015 Modified, and <br /> • Benzene,toluene,ethylbenzene and total xylenes(BTEX),fuel additives di-isopropyl ether <br /> (DIPE),ethyl tertiary-butyl ether(ETBE),methyl-tertiary-butyl ether(MTBE),tertiary-amyl <br /> methvl ether (TAME), tertiary butanol (TBA), 1,2-dichloroethane (1,2-DCA) and 1,2- <br /> dibromoethane (EDB) in accordance with EPA Method 8260B <br />` . 3.0. FINDINGS <br /> Ground water elevation, flow direction, and gradient were determined from field data collected on <br /> 05 November 2004, the contaminant Impact to ground water was quantified from the laboratory <br /> analytical data <br /> 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> IThe elevation of ground water in each well was calculated by subtracting the depth to ground water <br /> from the surveyed well casing elevations(Table 1) For the November 2004 sampling event, depths <br /> to ground water ranged from 6 80 feet to 8 12 feet below the tops of the well casings Ground water <br /> elevations at the site ranged from 28 75 feet above mean sea level(MSL)in well MW-9 to 29 62 feet <br /> above MSL in well MW-1 <br /> IThe ground water flow direction was determined by contouring the ground water elevation data The <br /> ground water at the site was Inferred to be flowing to the north-northwest at an average gradient of <br />' 0 005 foot/foot The ground water contours are depicted on Figure 3 Elevation data from deep- <br /> screened well MW-6(screened between 27 and 32 feet bsg)was not used to determine ground water <br /> flow direction <br /> I <br /> • <br /> rAdvanced GeoEnvironment$I,Inc <br />