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5.0 SOIL-PORE GAS MONITORING In accordance with WDR Order No. R5-2007-0046, soil-pore gas probes are monitored semiannually using a field screening protocol, and soil-pore gas samples are only collected if field screening indicates methane concentrations greater than 2.5 percent. During the monitoring period, field screening of soil-pore gas probes was conducted on August 18, 2010. As shown on Table 6, no methane was detected in any of the soil-pore gas probes, and as a result, no samples were collected. 6.0 ANNUAL SUMMARY 6.1 GENERAL During the 2010 monitoring year, groundwater elevation measurements were performed quarterly and water quality monitoring points and soil-pore gas probes were sampled semiannually in accordance with WDR Order No. R5-2007-0046. All of the monitoring points are sampled for the monitoring parameters summarized in Table 1. Time-series plots depicting groundwater and surface water constituent concentrations and a tabular summary of the historical monitoring data are presented in Appendix D and in an electronic format in Appendix C. Piper diagrams of the semiannual data obtained in 2010 are included in Appendix D, and hydrographs of the detection monitoring wells, illustrating historic groundwater elevations, well screen elevations, and pump intake elevations are also included in Appendix D. Discussions of the historical trends in constituent concentrations are presented in Section 4. 6.2 GROUNDWATER Groundwater elevations have remained relatively static over the past year, reflecting seasonal precipitation patterns. Groundwater generally flows to the south across the site at a gradient of 0.001 to 0.005 ft/ft. However, during the March 2010 monitoring event groundwater was depicted to flow to the east-northeast. It is believed that this change from the typical groundwater flow direction was the result of heavy seasonal rains. Groundwater quality conditions beneath the French Camp Landfill during the 2010 monitoring year are generally similar to those observed in the previous monitoring year. Excluding field parameters, inorganic CLs were exceeded in wells MW-9A, MW-9B and MW-l0A during the monitoring year. Furthermore, statistically significant increasing trends were consistently noted for chloride in well MW-10A, and potassium and sulfate in well MW-9B. Decreasing trends were consistently noted for calcium,magnesium, and pH in wells MW-6A; chloride, specific conductance, and sulfate in well MW-7A; bicarbonate, magnesium, and nitrate as nitrogen in well MW-8A; pH in well MW-913; and nitrate as nitrogen in well MW-10A. During the first semiannual 2010 monitoring period, a low level concentration of chloroform was detected above the PQL in the sample collected from background well D:\2010-0030\FC_2SA10.doc 6