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rt3 October 2003 • AGE-NC Project No. 95-0106. 'Page 2 of-4. (MAI);a California Departmerit of Health Services-certified analytical laboratory for analysis. The r samples were analyzed for: 'Total petroleum hydrocarbons quantified as, gasoline (TPH-g) in' accordance with rEPA Method 8015-Modified, and • Benzene, toluene; ethylbenzene, and total xylenes (BTEX) and methyl tertiary-butyl ether r (MTBE) in accordance with EPA Method-8260. r' 3.0. FINDINGS rGround water elevation and flow direction were inferred from field data. The hydrocarbon impact to ground water was quantified by laboratory analysis of the ground water samples. r' 3.L GROUND WATER ELEVATION AND FLOW, DIRECTION . The relative ground water elevation ranged from 31.71 feet (MW-6 upper) to 32.73 feet (MW-2), decreasing an average of 0.97 feet since the March of 2003 monitoring event. The water table appears as a northerly plunging ridge; .the..east limb of the ridge flows toward the northeast at a rgradient of approximately 0.004 ft/ft 'and the west limb flows toward the north-northwest at a gradient of approximately 0.005 ft/ft. Groundwater elevation data-is presented in Table 1 while the contoured ground water elevation data is show' n on Figure 3. , 3.2. ANALYTIC.AL:RESULTS OF GROUND WATER SAMPLES Petroleurn hydrocarbons were detected in the ground water samples collected from monitoring wells MW-1 an&MW-4! TPH-g was detected iri concentrations of 2,500-rnicrograms per liter.(pg/1) and 2,100µg/1 in samples form MW-1 and MW-4;repectivley(Figure 4)'. Benzene was also detected at •450 µg/l and.,42µg11 in samples MW-I and MW-4, respectively. Other concentrations of volatile aromatic compounds detected in samples MW-1 and MW-,4 include 150µg/1 and 5.1 µg/1 oftoluene, r' 5'1 µg11 and'91 µg/1 of ethylbenzene'and 220;µg/1 and 18'µg/1 of xylenes, respectively.' Neither TPH-g nor BTEX compounds.were detected in'the ground water samples from monitoring wells MW-2, MW73, MW-5, MW-6 (upper), MW-6 (lower) and MW-7: MTBE was not detected in any of the ground water samples. Analytical,results of ground water ' sam le summarized on Table 2. The laborato re'ort MAI Lab-IDs 0306496-OOIA throw • p s.are summ ry p ( through: 0306496`-'O08A), QA/QC and chain-of-custody are included in Appendix C.. Advanced GeoEnvironmental,Inc. .