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t28 December 2005 • AGE-NC Project No 98-0511 ' Page 2 of 4 approximately 7 gallons of water had been evacuated Ground water temperature, pH, and conductivity were measured at regular intervals during the purge process using an Oakton water analyzer Field data sheets are included in Appendix C Purged water was stored on-site in properly ' labeled, Department of Transportation (DOT)-approved 55-gallon drums ' 23 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES Following purging, the depth to ground water was re-measured to ensure that a minimum of 80% ' well-volume recharge had been achieved prior to sampling Water samples were collected from each purged well using dedicated,disposable plastic bailers 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 California Department of Health Services (DHS)-certified ' laboratory, and analyzed for - Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA . Method 8015M, Benzene, toluene, ethylbenzene, and total xylenes (BTEX) and fuel additives di-isopropyl I ether(DIPE),ethyl tertiary-butyl ether(ETRE),methyl tertiary-butyl ether(MTBE),tertiary- amyl methyl ether (TAME), tertiary-butyl alcohol (TBA), 1,2-dibromoethane (EDB), 1,2- dichloroethane(1,2-DCA), ethanol, and methanol in accordance with EPA Method 8260B f I3.0. FINDINGS Ground water elevation and flow direction were determined from field data Hydrocarbon impact to ground water was inferred from laboratory analysis of ground water samples 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION For the June 2005 ground water monitoring event, the elevation of ground water in each well was calculated by subtracting the depth to ground water from the surveyed casing elevation (Table 1) Depths to ground water ranged from 14 40 feet to 15 03 feet below the tops of the well casings Ground water elevations at the site ranged from 2 71 feet below mean sea level(MSL)in well MW-5 to 3 74 feet above MSL in well MW-1 Ground water at the site was inferred to flow generally • toward the northwest on-site at gradients ranging between 0 004 foot/foot(ft/ft) and 0 015 ft/ft and Advanced GeoEnvironmental,Inc