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are sampled for the monitoring parameters summarized in Table 1. Time-seriesP lots depicting groundwater and surface water constituent concentrations and a tabular ! summary of the historical monitoring are presented in Appendix D and an electronic format is included in Appendix C. Piper diagrams of the quarterly data obtained in 2007 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 south to southeast across the site at a gradient of approximately 0.002 Mt. Groundwater quality conditions beneath the French Camp Landfill during the 2007 monitoring year are generally similar to those observed in the previous monitoring year. Generally, calculated CLs for the general chemistry parameters were consistently exceeded in wells MW-9B and MW-10A, and intermittently in wells MW-6A, MW-8A, and MW-9A. Furthermore, statistically significant increasing trends were consistently noted for chloride in well MW-l0A and for sulfate in well MW-9B, while decreasing trends were consistently noted for specific conductance and sulfate in well MW-7A, pH in well MW-6A, and nitrate as nitrogen in wells MW-8A and MW-1 OA. Excluding ! confirmed laboratory contaminants, trace level concentrations of 1,2-DCA were measured in well MW-9B during the second, third, and fourth quarter 2007 monitoring periods, and concentrations of TCFM were detected above the PQL in well MW-9A during the first, second and third quarter monitoring periods and at a trace level during the fourth quarter 2007 monitoring period. For leachate monitoring well MW-2, no VOCs were detected in samples from this well during the 2007 monitoring year. 6.3 SURFACE WATER Surface water elevations at the stream gauging stations have remained relatively static over the past year, reflecting tidal patterns. Surface water generally flows west toward the San Francisco Bay. Water quality conditions for surface water at the French Camp Landfill during the 2007 monitoring year are generallysimilar to those observed in the previous monitoring years. Although CLs were exceeded for bromoform and dibromochloromethane at surface water station SW-2 during the first quarter 2007 monitoring period, and for carbon disulfide at surface water stations SW-1 during the second quarter 2007,none of these VOCs were confirmed in retests suggesting that the primary results were the result of laboratory and/or field contamination. During the 2007 monitoring year, only turbidity concentrations in all three surface water stations have exhibited an increasing trend. D:\2003_021\FC_4Q07.doc 6 Geologic Associates