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16 October 2006 <br /> AGE-NC Project No. 98-0520 <br /> ' Page 2 of 10 <br /> vials without a sample preservative. After collection, the samples were properly labeled, placed in <br /> a chilled container and transported under chain of custody to Cal Tech Environmental Laboratories <br /> (CTEL),a State of California Department of Health Services(DHS)-certified analytical laboratory, <br /> for analysis. The samples were analyzed for: <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> ' Method 8015M and <br /> • Benzene, toluene, ethyl-benzene, and xylenes (BTEX) and fuel additives methyl tertiary- <br /> butyl ether(MTBE),tertiary butanol (TBA), di-isopropyl ether(DIPE), ethyl tertiary-butyl <br /> ether (ETBE), tertiary-amyl methyl ether (TAME), 1,2-dichloroethane (1,2-DCA), and <br /> 1,2-dibromoethane (EDB) in accordance with EPA Method 826013. <br /> 3.0. FINDINGS <br /> ' Ground water elevation and flow direction were determined from field data collected on 09 June <br /> 2006. Hydrocarbon-impact to ground water was quantified from laboratory analysis of the ground <br /> water samples. <br /> 3.1. GROUND WATER ELEVATION AND GRADIENT <br /> The elevation of ground water in each well was calculated by subtracting the depth to ground water <br /> ' from the surveyed casing elevations (Table 1). Depths to ground water ranged from 16.42 feet <br /> (MW-7)to 17.54 feet(MW-6)below the tops of the well casings.Ground water elevation at the site, <br /> not including MW-6, averaged approximately 22.30 feet above mean sea level (MSL). <br /> The ground water flow direction was determined using ground water elevation data from water table <br /> ' wells MW-1 through MW-5 and MW-7 through MW-10;the elevation data from well MW-6 was <br /> not utilized because the well is deep-screened. At the time of the June 2006 monitoring event, <br /> ground water was inferred to be generally flowing toward the west and southwest at a gradient <br /> between 0.0005 foot/foot (ft/ft) and 0.001 ft/ft. Figure 3 illustrates the contoured ground water <br /> elevations as measured on 09 June 2006. <br /> ' 3.2. ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> ' TPH-g was reported in the ground water samples collected from wells MW-2,MW-3 and MW-5 at <br /> concentrations ranging from 450 micrograms per liter (µg/l) in well MW-2 to 8,800 µg/l in well <br /> Advanced CeoEnvironmental,Inc. <br /> t <br />