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28 May 2004 <br /> AGE-NC Project No 99-0645 <br /> Page 2 of 4 <br /> 2 12 Collection and Analysis of Ground Water Samples <br /> Prior to collection of ground water samples,the depth to ground water was measured in each purged <br /> well to ensure that a minimum of 80% of the well volume had recharged A water sample was <br /> collected from each well using a new disposable plastic bailer Each water sample was transferred <br /> into three chilled 40-m1 volatile organic analysis (VOA) vials containing 0 5 ml hydrochloric acid <br /> (18%) as a sample preservative and one 1-liter amber bottle After collection, the samples were <br /> labeled and placed in a chilled container for transportation under chain-of-custody to Cal Tech <br /> Environmental Laboratories,a California Department of Health Services(DHS)-certified analytical <br /> laboratory, in Paramount, California Each sample was analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline and diesel(TPH-g and TPH-d)by EPA <br /> Method 8015M, <br /> • Benzene,toluene, ethylbenzene and total xylenes(BTEX) and the oxygenated fuel additives <br /> methyl tertiary butyl ether(MTBE),tertiary butyl alcohol(TBA),di-isopropyl ether(DIPE), <br /> ethyl tertiary butyl ether (ETBE) and tertiary amyl methyl ether (TAME), ethyl-dibromide <br /> (EDB) and 1,2- dichloroethane (1,2-DCA) by EPA Method 8260 Modified <br /> 3.0. FINDINGS <br /> Ground water elevation and flow direction were determined from field data Hydrocarbon impact <br /> to ground water was inferred from laboratory analysis of the samples <br /> 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION <br /> Depth to ground water at the site on 11 March 2004 ranged from 85 78 feet to 86 09 feet below the <br /> monitoring well casing tops The ground water elevation in each well was calculated from this data <br /> The ground water elevations ranged from wells MW-Ir and MW-3 were each 40 53 to 40 55 feet <br /> below mean sea level (MSL), respectively The average increase of 9 3 feet from the October 2003 <br /> monitoring event is recorded in Table 1 <br /> On 02 June 2004, the well head elevation for all on-site monitoring wells were re-surveyed The <br /> March ground water flow direction was estimated to flow toward the southwest to west, while the <br /> June ground water flow direction was estimated to flow toward the south to southeast These <br /> directions were contrary to prior sampling events Figure 3 illustrates the contoured ground water <br /> elevations <br /> Advanced GeoEnvironmental,Inc <br />