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I 26 July 2000 AGE-NC Pi oject No 95-0111 ' Page 2 of 4 located in Pacheco, California Each sample was analyzed fol the following I • Total pets oleum hydi ocal bons quantified as gasoline and diesel(TPH-g and TPH-d)by EPA ' Method 8015 Modified for each range of hydrocarbons, respectively, • Volatile ai omatic compounds - benzene, toluene, ethylbenzene and total xylenes (BTE&X) Iand methyl tertiary-butyl ether (MTBE) by EPA Method 8020, and • Oxygenated compounds - di-isopropyl ether (DIPE), ethyl tertiary butyl ether (ETBE), I MTBE, tertiary amyl methyl ether (TAME) tertiary butyl alcohol (TBA) by EPA Method 8260 Modified ' 3.0. FINDINGS ' 3 1 GROUND WATER FLOW DIRECTION AND GRADIENT The I elative gi ound water elevation in each well was calculated by subtracting the depth to ground lie water fi om the sur veyed 1 elative casing elevations The depths to ground water and relative g1 ound water elevations are tabulated in Table 1 The depth to g1 ound water ranged from 6 17 feet below the well casing (bwc) in MW-4 to 9 38 feet bwc in MW-1 The relative ground water elevation inti eased 0 43 feet over the last quarter The gi ound water flow direction at the site is towards the north-northeast which is consistent with 1 esults obtained fi om previous quarterly monitoring events I conducted The ground water gi adient was appy oximately 0 0055 ft/ft The 1 elative ground water rso- elevatlon contour s ale depicted 1n F1gui e 3 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES ' The analytical i esults from the sampling event conducted on 17 April 2000 are as follows • TPH-g was detected in samples collected from monitoring wells MW-2, MW-4 and MW-5 ' at concentl atlons of 120 micrograms per liter (µg11), 70 µg11, and 130 pg/l, i espectively • TPH-d was detected 1n samples fiom wells MW-2 and MW-5 at concentrations of 74 µg/l ' and 4,100 µg/l, 1 espectively • Benzene was detected in samples collected from wells MW-1 and MW-2 at concentl atlons of 0 77 µg/l and 0 66 gg/l, respectively Ethylbenzene was detected in well MW-2 at a concentration of 8 4 pg/1 Xylenes were detected 1n the samples from well MW-2 at a . concentration of 4 1 µg/1 I0 MTBE was detected by EPA Method 8260 Modified in samples collected from wells MW-1, Advanced GeoEnvironmenlal Inc