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I 1001 February 2006 AGE-NC Project No 00-0697 ' 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 containing 0 5 ml 18%hydrochloric acid solution as a sample preservative,and into 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)-certified analytical laboratory, for analysis The samples were analyzed for • Total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d, respectively) in accordance with EPA Method 8015M, and • 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-dibromoethane (EDB), and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B I 3.0. FINDINGS 1 • Ground water elevation and flow direction were inferred from field data, hydrocarbon impact to ground water was quantified by laboratory analysis of the ground water samples 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION The elevation of ground water in each of the monitoring wells was calculated by subtracting the depths to ground water from the surveyed relative casing elevations (Table 1) Depths to ground water ranged from 5 02 feet(MW-4)to 6 35 feet(MW-1)below the tops of the well casings Ground water elevation at the site ranged from 17 78 feet (MW-4) to 18 I5 feet (MW-1) below mean sea level (MSL), and averaged approximately 18 02 feet below MSL, indicating a decrease in ground water elevation of approximately 0 45 feet since the last monitoring event in August 2005 During this monitoring event, the ground water levels in all the wells were below the tops of the well screens During the November 2005 ground water monitoring event, ground water at the site was inferred to be flowing toward the west-northwest under a hydraulic gradient of approximately 0 007 foot/foot (ft/ft) Figure 3 illustrates the contoured ground water elevations as measured on 16 November 2005 • lAdvanced GeoEnvironmental,Inc I �