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' 24 August 2005 • AGE-NC Project No 02-0950 Page 2 of 4 ' preservative 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,for analysis The samples were ' analyzed for • Total petroleum hydrocarbons quantified as gasoline (TPH-g) and diesel (TPH-d) in accordance with EPA Method 8015 Modified, • Benzene,toluene,ethylbenzene,and total xylenes(BTEX)and fuel additives methyl tertiary- butyl ether(MTBE), tertiary-butyl alcohol(TBA),di-isopropyl ether(DIPE), ethyl tertiary- butyl ether(ETBE),tertiary-amyl methyl ether(TAME), 1,2-dichloroethane(1,2-DCA),and 1,2-dibromoethane (EDB) in accordance with EPA Method 8260B, and 3.4. FINDINGS Ground water elevation, flow direction, and gradient were determined from field data collected on '. 24 June 2005 The contaminant impact to soil and ground water was quantified from laboratory analytical data ' 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION At the time of the June 2005 sampling event,depths to ground water ranged from 17 11 feet(MW-3) to 17 45 feet(MW-2)below the tops of the well casings Ground water elevation at the site averaged approximately 9 43 feet below mean sea level(MSL),indicating a overall average increase in ground water elevation of approximately 0 15 feet between March 2005 and June 2005 (Table 1) Ground water elevation increased in both MW-1 and MW-2, but decreased slightly in MW-3 During this monitoring event,the ground water levels in the wells were at least 2 feet below the tops of the well screens,indicating that the wells are screened properly to yield representative shallow ground water samples The general ground water was inferred to be flowing toward the northeast under a hydraulic gradient of approximately 0 002 foot/foot (ft/ft) Figure 3 illustrates the contoured ground water elevations as measured on 24 June 2005 Ground water directions and gradients can vary greatly, as they are influenced by seasonal changes to the static water table Advanced Geo&nvironmental,Inc