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Concentration Limits <br /> For DMP monitoring wells at the French Camp Landfill, concentration limits (CLs) <br /> provided in the WDRs are used for the water quality protection standards (WQPS). <br /> Based on a comparison of the data obtained during the current monitoring period, the <br /> following analytes were found to exceed a CL: <br /> CONSTITUENT Concentration I DMP Monitoring Wells <br /> Limit MW-6A* MW-7A* MW-8A MW-9A MW-9B MW-10A <br /> GENERAL CHEMISTRY(mg/1) <br /> Chloride 249 450 1 480 <br /> Specific Conductance(µmhos/cm) 2500 2879 <br /> H 6.9-10.21 6.82 6.84 <br /> Total Dissolved Solids(TDS) 1600 1800 <br /> Chloroform 0.5 2.8 <br /> Trichlorofluoromethane 0.5 2.5 <br /> NOTES: (*)—Background Well. <br /> Trend Analysis <br /> In order to evaluate changes in water quality in DMP wells at the French Camp Landfill, <br /> historical groundwater data were evaluated using Sen's Slope trend analyses to determine <br /> if statistically significant increasing or decreasing trends were evident. Trend analyses, <br /> performed by Herst & Associates, are presented in Appendix D and summarized below. <br /> Well Number Increasing Trends Decreasing Trends <br /> MW-6A None Apparent Calcium, Magnesium,pH <br /> MW-7A None Apparent Chloride, Specific Conductance,TDS <br /> MW-8A None Apparent Bicarbonate,Chloride,Magnesium,Nitrate-N,TDS <br /> MW-9A None Apparent Nitrate-N,TCFM <br /> MW-9B Potassium, Sulfate pH <br /> MW-10A Chloride Nitrate-N <br /> During the monitoring period, statistically significant increasing trends were calculated <br /> for potassium and sulfate in well MW-913, and for chloride in well MW-10A. However, <br /> with the exception of chloride in well MW-10A, none of the constituents that exceeded a <br /> WDR established CL exhibited a statistically significant increasing trend. In January <br /> 2005 a No Release Demonstration(NRD) for groundwater monitoring well MW-l0A <br /> was performed (Herst, 2005) in response to CL exceedances of chloride and TDS. The <br /> NRD concluded that French Camp Landfill, located within the central Stockton area, has <br /> been impacted by saltwater intrusion and the elevated chloride and TDS concentrations <br /> measured in well MW-l0A are believed to be the result of this condition and not the <br /> result of landfill-related impacts. In addition, one or more statistically significant <br /> decreasing trends were calculated, for inorganic constituent concentrations, in all of the <br /> groundwater monitoring wells at the French Camp Landfill. For organic constituents, a <br /> decreasing trend was also calculated for TCFM in well MW-9A. <br /> C:12012-0027\FC1SA12.doc 4 Cleo-Logic Associates <br />