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' 29 October 2004 . AGE-NC Project No 01-0877 ' Page 2 of 4 _ analysis(VOA)vials containing 0 5 ml 18%hydrochloric acid solution as a sample preservative,and ' one 1-liter amber bottle without 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 State of California Department of Health Services (DHS)-Environmental Laboratory Accreditation Program certified(#2424)analytical laboratory,for analysis The samples were analyzed for Total petroleum hydrocarbons quantified as gasoline(TPH-g),diesel(TPH-d),and motor oil (TPH-mo) in accordance with EPA Method 8015 Modified, and ' Benzene,toluene, ethylbenzene, and total xylenes(BTEX)and volatile organic compounds 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 8260 I3.0. FINDINGS '• Ground water flow direction, elevation, and gradient were determined from data collected in the field The hydrocarbon impact to ground water was quantified by the laboratory data obtained from ' the ground water samples ' 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION At the time of the July 2004 sampling event,depths to ground water ranged from 26 95 to 27 66 feet ' below the tops of the well casings (Table 1) The average ground water elevation at the site was approximately 17 29 feet below mean sea level (MSL), which indicates a decrease in the static ground water elevation of approximately 0 73 feet since the last monitoring event Ground water was ' inferred to flow in a northeast-plunging ridge, with water north of the ridge flowing to the north under a gradient of approximately 0 006 foot/foot and water to the south of the ridge flowing eastward under a gradient of approximately 0 004 foot/foot (Figure 3) During the July 2004 ' monitoring event,ground water levels were within the screened Interval of each well,indicating that the wells were screened properly to yield representative ground water samples I3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES ' TPH-g was detected in all ground water samples at concentrations ranging from 31,000 micrograms • per liter(µg/1)in sample MW-4 to 190,000µg/1 in sample MW-3 BTEX compounds were detected ' Advanced GeoEnvironmental,Inc I