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plots, general chemistry and metals constituent concentrations are generally consistent <br /> with historical concentrations. During the monitoring period, chloroform was measured <br /> above the PQL in the samples collected from background well MW-6A. Although <br /> previous retest samples confirmed the presence of chloroform in well MW-6A, the <br /> presence of chloroform is not believed to the result of a release from the landfill. <br /> Chloroform has been rarely detected in on-site wells and background well MW-6A is <br /> located approximately 1200 feet cross-gradient from the landfill. Of note, a similar, <br /> slightly higher concentration of chloroform was also detected in the QA/QC field blank. <br /> Concentration Limits <br /> For DMP monitoring wells at the French Camp Landfill, concentration limits(CLs) as <br /> established 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 IDMP Monitoring Wells <br /> Limit MW-6A* MW-7A* MW-8A MW-9A MW-9B MW-10A <br /> E <br /> ERAL CHEMISTRY(mg/t)ride 249 460 <br /> tile Organic Compounds(µg/1) <br /> oform 0.5 0.83** <br /> NOTES: (*)—Background Well. <br /> Suspected field/lab contaminant. <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 significant increasing or decreasing trends were evident. Trend analyses, performed by <br /> 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, Sulfate,TDS <br /> MW-8A None Apparent Bicarbonate,Calcium,Magnesium,Nitrate-N, <br /> Sodium <br /> MW-9A None Apparent None Apparent <br /> MW-913 Potassium,Sulfate H <br /> MW-10A Chloride Nitrate-N <br /> As shown above, CLs were exceeded for a constituent in the samples collected from <br /> wells MW-9A, and MW-9B. It should be noted, however, none of the constituents that <br /> exceeded a CL exhibited a statistically significant increasing trend during the monitoring <br /> period. <br /> W2010-0030TC_ISA10.doc <br /> 4 Geologic Associates <br />