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TD concentrations measured in well MW-l0A are believed to be the result of this condition and not the result of landfill-related impacts. 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, one VOC (chloromethane)was measured at a trace concentration in the duplicate sample collected from leachate monitoring well -2 during the monitoring period. However, no VOCs were detected in the primary sample, and is a suspected laboratory contaminant. 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. 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 Sanitas, 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, one VOC (carbon disulfide)was measured above the PQL in the sample collected from station SW-1. In response to the detection of carbon disulfide in station SW-1, retest samples were collected on June 30, 2009. The results of the retest samples indicate that no VOCs were detected and the carbon disulfide concentration measured in the primary sample is concluded to be a false positive. As has been the case historically, statistically significant increasing trends for turbidity were calculated at surface water stations SW-1, S -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 February 17, and May 17, 2009 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. D:UO09-0018\FC_1 SA09.doc 5 Geologic Associates