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06 January 2006 <br />• AGE-NC Project No 99-0559 <br /> Page 3 of 7 <br /> water sample containers were properly labeled, placed in a chilled container and transported under <br /> chain of custody protocol to Cal Tech Environmental Laboratories(CTEL),a California Department <br /> of Health Services-certified laboratory, for analysis The ground water samples were analyzed for <br /> the following <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> Method 8015 Modified, and <br /> • Benzene, toluene, ethylbenzene and xylene (BTEX) and the fuel additives tertiary butanol <br /> (TBA), di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), tertiary-amyl methyl <br /> ether (TAME), methyl tertiary-butyl ether (MTBE), 1,2-dibromoethane (EDB) and <br /> 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B <br /> 3.0. FINDINGS <br /> Ground water elevations were determined by subtracting the measured depths to ground water from <br /> the surveyed casing elevations Ground water flow directions were determined by contouring the <br /> water elevations on a scaled site plan Contaminant impact to ground water was assessed by <br /> laboratory analysis <br /> I <br /> 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> The elevation of ground water in each monitoring well at the time of the monitoring event was <br /> calculated by subtracting the depth to ground water from the surveyed casing elevation, current and <br /> historical ground water elevation results are provided in Table 1 Each ground water elevation is <br /> grouped according to the HU on the assumption that the elevation will reflect hydrostatic conditions <br /> within the designated HUs <br /> HU1 and HU2 The depth to ground water in monitoring wells MW-1 through.MW-4 and the depth <br /> to ground water measured in wells MW-5A through MW-7A ranged between 54 51 and 58 83 feet <br /> below the top of casing (btoc) <br /> The ground water elevation was calculated between 29 89 feet (MW-1) and 33 55 feet (MW-7A) <br /> below mean sea level(MSL),the ground water elevation averaged 32 28 feet below MSL,a decrease <br /> of an average of 2 78 feet since the June 2005 monitoring event The top of the ground water table <br /> remained within the screened interval of these wells At the time of the November 2005 monitoring <br /> event, ground water flow within the interval of HU1 and HU2 wells was inferred to be toward <br /> Advanced GeoEnvironmental,Inc <br />