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12 June 2012 AGE-NC Project No. 99-0682 Page 3 of 7 MW-10, with the exception of benzene and ethylbenzene in samples collected from MW-9; BTEX compounds were detected at maximum concentrations of 6,400 pg/I benzene, 15,000 pg/I toluene, 3,200 pg/I ethylbenzene, and 13,300 pg/I total xylenes (MW-8). • Lead scavenger 1,2-DCA was detected in samples collected from wells MW-7, MW-8, and MW-10 at concentrations ranging between 12 pg/I (MW-10)and 65 pg/I (MW-8). The fuel oxygenate TAME was detected in samples collected from wells MW-7, MW-8, and MW-10 at concentrations ranging between 6.1 pg/I (MW-10)and 29 pg/I (MW-8). • Figure 6 depicts the approximate lateral extent of dissolved COC within this deep water-bearing zone on-site and off-site. Water-Bearing Zone: 125 to 135 feet bsg • Depth to ground water and ground water elevation in well MW-1 C were 25.20 feet btoc and 12.00 feet below NAVD88, respectively (Table 1). • No analytes were reported at or above laboratory detection limits in ground water samples analyzed from well MW-1C. Water-Bearing Zone: 140 to 150 feet bsg • Depth to ground water and ground water elevation in well MW-1 D were 25.58 feet btoc and 11.96 feet below NAVD88, respectively (Table 1). Baseline Ground Water Sampling Results: Pre-ISCO Remediation • Various dissolved metals (barium [Ba], aluminum [AI], calcium [Ca], iron [Fe], magnesium [Mg], manganese [Mn], and sodium [Na]) were detected in ground water samples collected from wells MW-1A, MW-6, MW-7, and MW-8, with the exception of Fe from MW-8. Barium concentrations in wells MW-1A, MW-6, MW-7, and MW-8 and Al concentrations in wells MW-6, MW-7, and MW-8 were all below their respective State of California Primary Maximum Contaminant Levels (MCLs) for drinking water; however, the concentration of Al in well MW-1A was just above the State of California Primary MCL and all concentrations of Al were above the State of California Secondary MCL. Concentrations of Fe and Mn detected in wells MW-1A, MW-6, and MW-7 were significantly above the State of California Secondary MCLs for drinking water. Concentrations of Ca, Mg, and Na all appear to be within normal background levels. Advanced GeoEnvironmental,Inc.