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3 <br /> I15 January 2001 A <br /> • AGE-NC Protect No 99-0624 <br /> IPage,2 of 4 <br /> I _2 2 COLLECTION AND ANALYSTS OF GROUND WATER SAMPLES <br /> Water samples were collected from each monitoring well using new disposable bailers after allowing <br /> Ithe wells to achieve a minimum 80% recovery of the pre-purge water volume The samples were <br /> transferred into laboratory-supplied 40-m1 EPA-approved VOA vials containing 0 5 ml 18% <br /> hydrochloric acid as a sample preservative The sample vials were then labeled with the monitoring <br /> Iwell designation,date,time of sampling and the sampler's Initials The samples were transported In <br /> a chilled container under chain of custody to McCampbell Analytical, Inc (MAI), a California <br /> I Department of Health Services(DHS)-certified analytical laboratory for analysis The samples were <br /> analyzed for <br /> + Total petroleum hydrocarbons quantified as gasoline (TPH-g) In accordance with EPA <br /> Method 5030/8015 Modified, <br /> + Volatile aromatic compounds - benzene, toluene, ethylbenzene, and total xylenes (BTEX) <br /> Iand methyl tertiary butyl ether(MTBE) In accordance with EPA Method 8020, and <br /> • Fuel oxygenates - tertiary butanol (TBA), di-isopropyl ether,(D1PE), ethyl tert-butyl ether <br /> I • (ETBE), tert-amyl methyl ether (TAME), and MTBE in accordance with EPA Method <br /> 8260M <br /> I <br /> 3.0. FINDINGS <br /> IThe ground water elevation In each well was determined by subtracting the measured depths-to- <br /> water from the surveyed casing elevations and are presented in Table 1 Ground water flow direction <br /> was determined by contouring the ground water elevations on a scaled site plan (Figure 3) <br /> ' Hydrocarbon-Impact and MTBE-Impact to ground water were assessed from laboratory analysis of <br /> the ground water samples <br /> 3 1 GROUND WATER ELEVATION AND GRADIENT <br /> IDepths to ground water ranged from 51 63 feet to 52 75 feet below the tops of the well casings <br /> Ground water elevations at the site ranged from 13 25 feet (MW-4) to 13 44 feet (MW-1) below <br /> mean sea level The top of the saturated zone occurred within the screened Intervals of all the ' <br /> monitoring wells <br /> IThe ground water flow direction was determined by contouring the ground water elevation data The <br /> • ground water underlying the site was Inferred to have an average gradient of 0 002 ft/ft and flow In <br /> Advanced GcoE nvi ron mental,Inc <br /> 1 <br />