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4.6 SURFACE-WATER MONITORING Fourth quarter 2007 field and laboratory results for surface-water monitoring stations (SW-1, SW-2, and SW-3) 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, there were no CL exceedances for surface water samples collected during the fourth quarter 2007. Trend analyses indicate that only turbidity at surface water stations SWA, SW-2, and SW-3 depict statistically significant increasing trends. Given that 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 facility. Stream gauging was performed on November 20, 2007 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 Soil-pore gas monitoring at the French Camp Landfill was conducted on November 21, 2007. Specifically, field measurements of oxygen, carbon dioxide, methane, and nitrogen were recorded in volumetric percent for probes SGP-1 A, SGP-2A, SGP-3, SGP-4A, SGP-5A, SGP-6A, SGP-7A, and SGP-8A using a Landtec GEM 2000. In addition, soil- pore gas samples were collected for analysis of oxygen, carbon dioxide, methane, nitrogen, and VOCs and these results are presented in Table 6. During the current monitoring period no methane was detected by field instruments or by the laboratory in any of the probes (Appendix C). Seven VOCs were detected in the samples collected from soil-pore gas monitoring probes during the current monitoring period, with the sample from probe SGP-3 containing the highest total concentration of VOCs. 6.0 ANNUAL SUMMARY 6.1 GENERAL During the 2007 monitoring year, groundwater elevation measurements and sampling of each of the monitoring points were performed at the French Camp Landfill on a quarterly basis in accordance with WDR Order No. R5-2007-0046. All of the monitoring points D:\2003_021\FC_4Q07.doc 5 Geologic Associates