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I13 November 2000 AGE-NC Project No 99-0624 ' Page 2 of 4 2 2 COLLECTION AND ANALYSTS OF GROUND WATER SAMPLES Water samples were collected from each monitoring well using new disposable bailers, after allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume The samples were transferred Into laboratory-supplied 40-m1 EPA-approved VOA vials containing 0 5 ml 18% I hydrochloric acid as a sample preservative The sample vials were then labeled with the monitoring well designation,date,time of sampling and the sampler's initials The samples were transported in a chilled container under chain of custody to McCampbell Analytical, Inc (MAI), a California Department of Health Services(DHS)-certified analytical laboratory for analysis The samples were analyzed for I • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA Method 5030/8015 Modified, • Volatile aromatic compounds, including benzene, toluene, ethylbenzene, and total xylenes I (BTEX)with methyl tertiary butyl ether(MTBE)in accordance with EPA Method 8020,and • Fuel oxygenates,including tertiarybutanol(TBA),di-isopropyl ether(DIPE),ethyl tert-butyl • ether(ETBE), tert-amyl methyl ether(TAME),and MTBE in accordance with EPA Method 8260M 3.0. FINDINGS IThe ground water elevation in each well was determined by subtracting the measured depths-to- water from the surveyed casing elevations and are presented in Table 1 Groundwater flow direction was determined by contouring the ground water elevations on a scaled site plan (Figure 3) - Hydrocarbon-impact and MTBE-impact to ground water were assessed from laboratory analysis of the ground water samples I 3 1 GROUND WATER ELEVATION AND GRADIENT ' Depths to ground water ranged from 52 54 feet to 53 58 feet below the tops of the well casings Ground water elevations at the site ranged from 14 08 feet (MW-4) to 14 35 feet (MW-1) below Imean sea level The top of the saturated zone occurred within the screened intervals of all the monitoring wells IThe ground water flow direction was determined by contouring the ground water elevation data The • ground water underlying the site was inferred to have an average gradient of 0 003 ft/ft and flow in a southerly direction, fanning out towards the southwest and southeast Figure 3 illustrates the Advanced GeoEnvironmeotal,Inc I