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' 16 February 2004 AGE-NC Project No 99-0624 Page 2 of 4 2 2 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES I , Water samples were collected from each purged well using a Watera hydrolift 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 40-mI volatile organic analysis(VOA)vials containing 0 5 ml 18%hydrochloric acid 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-certified analytical laboratory The samples were analyzed for ' Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA Methods 5030/8015M, I Benzene, toluene, ethylbenzene and xylenes (BTEX) in accordance with EPA method 8260B, and • Fuel additives di-isopropyl ether(DIPE), ethyl tertiary-butyl ether(ETBE), methyl tertiary- butyl ether (MTBE), tertiary-amyl methyl ether (TAME), tertiary butanol (TBA), 1,2-dichloroethane (1,2-DCA) and ethylene dibromide (EDB) in accordance with EPA Method 8260B 3.0. FINDINGS Ground water elevation, flow direction, and gradient were determined from field data The contaminant impact to ground water was quantified by the laboratory analytical data 3 1 GROUND WATER GRADIENT AND DIRECTION At the time of the November 2003 sampling event, depths to ground water ranged from 53 26 feet to 54 40 feet below the tops of the well casings Ground water elevations at the site ranged from 14 90 feet below mean sea level (MSL) in well MW-4 to 15 21 feet below MSL in well MW-6 I (Table 2) During this monitoring event,the ground water levels in wells MW-1 through MW-4 and MW-6 were at least eight feet below the tops of the well screens, indicating that the wells are screened properly to yield representative shallow ground water samples The ground water elevation ' at the site increased approximately 125 feet between the September 2003 and November 2003 monitoring events Ground water on 14 November 2003, was Inferred to be flowing toward the south-southeast The average ground water gradient was determined to be between 0 002 ft/ft and 0 005 ft/ft Figure 3 Illustrates the contoured ground water elevations as measured on 14 November 2003 Advanced GeoEnvironmental,Inc I