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' 11 November 2002 ' <br /> i AGE-NC Project No. 95-0106 s <br /> Page 2of4 <br /> hydrochloric acid as a preservative. The sample vials were-then labeled with the monitoring well <br />' designation, date, time of sampling,and the sampler's initials. The samples were transported in a <br /> chilled container under chain of custody fo McCampbell Analytical, Inc. (MAI),' a California <br /> Department of Health Services-certified analytical laboratory for analysis. The 'samples were <br />' analyzed for: <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with <br />' EPA Method 8015 Modified, and <br /> • Benzene, toluene, ethylbenzene, and total xylenes'(BTEX) and methyl tertiary-butyl ether <br />' (MTBE) in accordance with EPA Method 8021. <br />'S 3:0. FINDINGS <br /> Ground water elevation and flow direction were inferred from field data; hydrocarbon-impact to <br /> 1 ground water was was quantified by laboratory analysis of the ground water samples. <br />' 3.1. GROUND WATER ELEVATION AND FLOW DIRECTION <br /> The relative ground water elevation ranged from 32.05 feet (MW-6 upper and MW-6 lower) to <br />' 32.89 feet (MW-2), decreasing an average of 0.69 feet since the May 2002 monitoring event. The <br /> Water table appears as a north plunging ridge; the east limb of the ridge flows toward the northeast <br />' at a gradient of approximately 0.005 ft/ft, and the west limb flows toward the north-northwest at a <br /> gradient of approximately 0.007 ft/ft. Ground water elevation data, is presented in Table 1; the <br /> contoured ground water elevation data is'shown on Figure 3. <br /> 3.2. ANALYTICAL RESULTS,OF GROUND WATER SAMPLES <br /> 1 <br /> Petroleum hydrocarbons were detected in the ground water samples collected from monitoring wells <br /> MW-1 and MW-4; MW-1 is located slightly cross and down-gradient from the former UST <br />'. excavation and MW=4 is located further north in the generally down-gradient direction. TPH-g was' <br /> detected at concentrations of 570 micrograms per liter(µg/1)and 1,600µg'/1,respectively,in'samples <br />' from the two wells. Benzene was detected at 150 µg/1 and 45 µg/1 in samples from MW_1-and <br /> MW-4, respectively. Other concentLratiojis of volatile aromatic compounds detected in samples <br /> MW-1 and MW-4 include 9.6 g/l and .0 µg/l toluene, 13,0 1 and-4.2 µg/l ethylbenzene and <br /> 13 µg/1'and 28 µg/1 xylenes, respectively. �i `� o <br /> g .-,A <br />'. Advanced GeoEnvironmental,;Inc. <br /> ' <br />