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20 July 2007 AGE-NC Project No. 01-0886 Page 2 of 4 allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume.Each water sample was transferred into three laboratory-supplied, 40-milliliter (ml) volatile organic analysis (VOA)vials and one 1-liter amber bottle.After collection,the samples were properly labeled,placed in a chilled container, and transported under chain of custody to Cal Tech Environmental Laboratories (CTEL), a California Department of Health Services (DHS)-certified analytical laboratory in Paramount, California. The samples were analyzed for: • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, respectively) in accordance with EPA Method 8015 Modified; and • Benzene,toluene,ethylbenzene,and total xylenes(BTEX)and fuel oxygenates di-isopropyl ether (DIPE), methyl tertiary-butyl ether (MTBE), ethyl tertiary-butyl ether (ETBE), tertiary-amyl methyl ether (TAME), tertiary-butyl alcohol (TBA), 1,2-dichloroethane (1,2-DCA), and 1,2-dibromoethane(EDB)by EPA Method 8260B. 3.0. FINDINGS Ground water elevation, flow direction, and gradient were determined from field data. The contaminant impact to ground water was quantified by laboratory analysis of ground water samples. 3.1. GROUND WATER GRADIENT AND FLOW DIRECTION At the time of the March 2007 sampling event, depths to ground water ranged from 57.00 feet (MW-1) to 57.53 feet (MW-2)below the well heads (Table 1). Ground water elevation at the site ranged from 26.67 feet(MW-2)to 26.93 feet(MW-1)below mean sea level (MSL), and averaged approximately 28.48 feet below MSL, indicating an increase in average ground water elevation of approximately 1.68 feet since the last ground water monitoring event in December 2006.During this monitoring event,the ground water levels in all three wells were above the screened intervals.Since the ground water level only exceeded the screened depth by an average of 2.79 feet,the ground water samples may still be representative of shallow ground water conditions. Ground water at the site was inferred to be flowing toward the east-northeast under a calculated hydraulic gradient of approximately 0.005 foot/foot(ft/ft).Figure 3 illustrates the contoured ground water elevations as measured on12 March 2007. Advanced GeoEnvironmental,Inc.