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two �, 12 February 2004 AGE-NC Project No. 00-0769 Page 2 of 7 L. 2.2.. COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES Ground water samples were collected from wells-MW-2B and MW-3B utilizing new,2-inch diameter disposable polyethylene bailers. Samples were collected from wells MW-1, MW-2A; MW-3B, MW-4A through MW-91)utilizing 3/8-inch or 5/8-inch diameter polyethylene tubing.The samples Lao were transferred into 40-m1 EPA-approved volatile organic analysis(VOA)vials containing 0.5 ml 18%hydrochloric acid as'a preservative: Care was taken to ensure that visible air bubbles were not present in the vials after filling and capping.The sample vials were then labeled with the monitoring well designation,date,time of sampling and the sampler's initials.Following collection,samples were placed in a chilled container and transported under chain-of-custody to Cal Tech Environmental i.. Laboratories (CTEL), a California Department of Health Services (DHS)-certified. analytical laboratory;and analyzed for: • Total petroleum hydrocarbons giiantified as gasoline (TPH-g) in accordance with EPA Method 8015 Modified; and • VOCs,including benzene,toluene,ethyl benzene and xylenes(BTEX)and the fuel additives methyl tertiary butyl ether.(MTBE), di-isopropyl ether.(DIPE), ethyl tertiary butyl ether a (ETBE),tertiary amyl methyl ether(TAME),tertiarybutyl alcohol(TBA),1,2 dibromoethane f �a.r (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with EPA Method 8260B. i.. 3.6.- FINDINGS ,. Ground water elevation,flow direction and gradient were inferred from field data.The hydrocarbon - impact.to groundwater was quantified by laboratory analysis of ground water samples. JA.i. GROUND WATER ELEVATION AND GRADIENT ' r Depth to groundwater was between 26.45 feet(MW-8A) and 31.02 feet-(MW-5E)below the tops ofthe'well casings(BTOC)on 17 December 2001 Ground water elevations ranged from;16.84 feet (MW-3B)t' 20.35 feet(MW-5E below mean sea level(MSL).However,well casing elevation-data f for wells MW-4 and MW-5 recorded-during the October 2003 site survey appears to be-erroneous. The well casing elevation data for wells MW-4 and MW-5 was not utilized in plotting ground water i elevation data. The ground water elevation data collected from the site was plotted for the informal HU.Also the • . ground water elevation data collected from the site and wells off-site were plotted for the informal ILW HU-2 through HU-4 hydrogeologic flow.units. Ground water elevation data from monitoring well MW-5 appears to be anomalusrand was not utilized in determining ground water gradient-and flow LW L — Advanced GeoEnvironmental,Inc.