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stations SW-1, SW-2, and SW-3; and for carbonate alkalinity at surface water stations SW-1 and SW-3 (Appendix D). In order to evaluate changes in water quality in 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, with the exception of the potassium concentration measured at surface water stations SW-2 and SW-3, no CLs were exceeded at surface water stations during the monitoring period. The samples obtained from both the upstream and downstream monitoring points during the first quarter 2011 monitoring event represent the highest potassium concentrations observed since potassium has been monitored(beginning in May 2005). It should be noted, however, that no increasing trends were noted for potassium during the current monitoring period. The presence of elevated potassium concentrations at both upstream and downstream monitoring locations indicates that the concentration limit exceedance for potassium at downstream location SW-3 may be due to a recent change in the natural surface water chemistry in the vicinity of the site. Stream gauging was performed on February 22, and May 22, 2011 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 February 28, 2011. 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 SUMMARY Groundwater quality conditions beneath the French Camp Landfill during the monitoring period are generally similar to those observed in previous monitoring periods. During the monitoring period, a CL was exceeded for one constituent in the samples collected from background well MW-6A, and compliance wells MW-9B and MW-10A. It should be noted, however, that none of the constituents that exceeded a CL exhibited a statistically significant increasing trend. During the monitoring period, no VOCs were detected in any of the groundwater monitoring wells, and there is no indication of a release from the facility. D:\2011-051\FC_1SA11.docx 5 GeoLogic Associates