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' 21 May 2002 <br /> AGE-NC Project No 97-0351 <br /> Page 2 of 4 <br /> ' upon retrieval,samples were transferred into chilled 40-m1 EPA-approved volatile organic analysis <br /> (VOA)vials containing 0 5 ml hydrochloric acid(18%) as a sample preservative and 1-liter amber <br /> bottles The samples were properly labeled, placed in a chilled container and transported under <br /> chain-of-custody to McCampbell Analytical, Inc (MAI), a California Department of Health <br /> Services-certified analytical laboratory located in Pacheco, California Each sample was analyzed <br /> in accordance with <br /> • EPA Method 8015 Modified for total petroleum hydrocarbons quantified as gasoline <br /> (TPH-g), <br /> • EPA Method 8020 for benzene,toluene,ethylbenzene and total xylenes(BTEX)and methyl <br /> tertiary-butyl ether (MTBE), and <br /> ' • EPA Method 8260 Modified for di-isopropyl ether(DIPE),ethyl tertiary butyl ether(ETBE), <br /> methyl tertiary butyl ether (MTBE), tertiary amyl methyl ether (TAME) and tertiary butyl <br /> alcohol (TBA), 1,2-dichloroethane (1,2-DCA) and ethylene dibromide(EDB), ethanol and <br /> ' methanol <br /> lie 3.0. FINDINGS <br /> Ground water elevation, flow direction and gradient were determined from field data collected on <br /> 30 March 2001, the contaminant impact to ground water was quantified from the ground water <br /> laboratory data <br /> 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> ' The relative elevation ofound water in each well was calculated <br /> gr by subtracting the ground water <br /> ' depth from the relative casing elevation The wells were surveyed relative to the top of well MW-1, <br /> which was assigned an arbitrary elevation of 10 feet <br /> ' Depths to ground water ranged between 8 94 feet and 9 90 feet below surface grade(bsg) Relative <br /> ground water elevations at the site ranged between 0 67 feet (MW-3) to 0 87 feet (MW-2) The <br /> relative ground water elevation data is summarized in Table 1 <br /> Ground water flow direction in the area of the western UST was toward the north-northeast at a <br /> gradient of approximately 0 0015 (ft/ft) as depicted in Figure 3 The close proximity of the western <br /> ' UST area to the Stockton Deep Water channel may have a significant effect on the local flow <br /> . direction and gradient <br /> ' Advanced GeoEnvironmental,Inc <br />