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' 01 February 2006 AGE-NC Project No 04-1239 ' Page 2 of 4 22 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES I Ground water samples were collected from each well using the Waterra inertia pump and dedicated ' tubing after 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 ' 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 in Paramount,California The ' samples were analyzed for • Total petroleum hydrocarbons quantified as gasoline(TPH-g) in accordance with EPA ' Method 8015M, and • Benzene,toluene,ethylbenzene,and total xylenes(BTEX)and fuel additives methyl terhary- 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 I3.0. 1F'INDINGS Ground water elevation and flow direction were inferred from field data, hydrocarbon impact to Iground water was quantified by laboratory analysis of the ground water samples I3 1 GROUND WATER GRADIENT AND FLOW DIRECTION At the time of the November 2005 sampling event, depths to ground water ranged from 20 13 feet I (MW-9) to 21 13 feet (MW-10) below the tops of the well casings Ground water elevation at the site ranged from 10 01 feet(MW-9) to 10 43 feet (MW-10) below mean sea level (MSL, Table 1), ` and averaged approximately 10 21 feet below MSL, indicating a decrease in-average ground water I elevation of 0 61 feet since the last monitoring event in September 2005 During this monitoring event, the ground water level was below the screened intervals in all three monitoring wells Ground water at the site was inferred to be flowing toward the southwest under a hydraulic gradient of approximately 0 007 foot/foot (ft/ft) Figure 3 illustrates the contoured ground water elevations as measured on 23 November 2005 r� Advanced GeoEnvironmental,Inc