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amec'0 <br /> • Since the removal of the stockpile in October 2007, groundwater sample <br /> concentrations at wells LPW-1, LPW-2, and LPW-3 appear to be stable or <br /> decreasing (Figures 6 through 11). <br /> French Camp Facility <br /> • Groundwater elevations measured in August 2010 ranged from 8.81 feet bmsl to <br /> 9.42 feet bmsl. The calculated groundwater elevations were within the range of <br /> historical elevations calculated for this Facility. The groundwater gradient at this <br /> Facility was calculated at 0.002 ft/ft with a flow direction to the north-northwest, <br /> similar to historical gradients and flow directions for this Facility. <br /> • Diesel-range total petroleum hydrocarbons were not detected above the laboratory <br /> reporting limit of 50 Ng/L in the groundwater samples from all three monitoring <br /> wells. For wells FCW-2 and FCW-3, this is consistent with historical monitoring <br /> results for these wells. During previous sampling events, TPH-diesel was detected <br /> above the WQG (100 pg/L) only in the groundwater samples from well FCW-1 (May <br /> 2004 to May 2007; May 2008; and May 2009). Although above the WQG, the <br /> laboratory noted that the petroleum hydrocarbons were classified as higher boiling <br /> point hydrocarbons. <br /> • Total and dissolved Cr concentrations were detected below the respective CDPH <br /> MCL (50 pg/L) in groundwater samples from the three monitoring wells. <br /> Groundwater sample results for total and dissolved Cr were within the range of <br /> concentrations detected during previous events. <br /> • Dissolved Cr VI concentrations were detected in groundwater samples from wells <br /> FCW-1, FCW-2 and FCW-3 at concentrations of 3.5 pg/L, 10 pg/L (FCW-2 <br /> duplicate at 10 pg/L) and 27 pg/L, respectively. Groundwater sample results were <br /> within the range of historical Cr VI concentrations for these wells. Dissolved Cr VI <br /> concentrations above the CDPH MCL (50 pg/L) have been observed at the <br /> upgradient well FCW-3 (May 2006 to November 2007; and in May 2009), and were <br /> detected above the reporting limit (0.5 Ng/L) since the initial sampling event in <br /> March 2002. <br /> • Since the removal of the stockpile in November 2005, groundwater sample <br /> concentrations from wells FCW-1, FCW-2, and FCW-3 appear to be stable or <br /> decreasing (Figures 12 through 17). <br /> AMEC Geomatrix, Inc. <br /> P:\10626.000.0\Docs\Semi-Annual Groundwater Monitoring&Sampling\Semi-Annual 1-10 12 <br />