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4.5 LEACHATE MONITORING The laboratory results for leachate monitoring well MW-2 are summarized in Table 3 and time-series concentration plots are presented in Appendix D. As shown on Table 3, no VOCs were detected in the sample collected from leachate monitoring well MW-2 during the monitoring period. 4.6 SURFACE-WATER MONITORING Field and laboratory results for surface-water monitoring stations (SW-1, SW-2, and SW-3) for the current monitoring period are summarized in Table 4. Locations SW-1 and SW-2 are located upstream of the landfill within the Walker and French Camp Sloughs, respectively, and are used as background sampling points, while SW-3 is located downstream of the landfill at the confluence of the two sloughs. During the monitoring period, trace level concentrations of toluene were detected in all three surface water stations. It should be noted, however,that toluene is a common field/laboratory contaminant. Water quality data from surface-water sampling stations were graphed on time-series concentration plots and are presented in Appendix D. For the surface water monitoring stations at the French Camp Landfill, CLs are used for the WQPS. The CLs shown in Table 4 were calculated by Herst& Associates using Sanitaso, a state-approved statistical software program using historical data from background surface water stations SW-1 and SW-2, and are presented in Appendix D. As shown in Table 4, with the exception of turbidity, no CLs were exceeded at surface water stations during the monitoring period. As has been the case historically, statistically significant increasing trends for turbidity were calculated at surface water stations SW-1, SW-2, and SW-3 (Appendix D). Since turbidity exhibits a statistically significant increasing trend at background surface water stations SW-1 and SW-2, the increasing trend in turbidity at SW-3 is unlikely to be indicative of an impact from the landfill. Stream gauging was performed on Mach 16, and May 22, 2010 at monitoring points SG-1 and SG-2 and the data are summarized in Table 5. As shown in Figure 1, monitoring point SG-1 is located upgradient in the Walker Slough and monitoring point SG-2 is located upgradient in the French Camp Slough. 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 D:\2010-0030\FC_1 SAI0.doc 5 Geologic Associates