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Afft eoog is Associates 4A Geologists, Hydrogeologists and Engineers January 22, 2008 JN: 2007-0044 Mr. Ross Atkinson Central Valley Regional Water Quality Control Board 11020 Sun Center Drive, #200 Rancho Cordova, CA 95670-6114 SUBJECT: FOURTH QUARTER 2007/ANNUAL MONITORING REPORT FRENCH CAMP LANDFILL SAN JOAQUIN COUNTY, CALIFORNIA On behalf of Forward, Inc. (Forward), Geo LO is Associates is leased to submit the fourth g P quarter 2007 and annual monitoring report for the French Camp Landfill, in compliance with the California Regional Water Quality Control Board - Central Valley Region (RWQCB) Waste Discharge Requirement (WDR) Order Number R5-2007-0046. This report summarizes standard observations and presents the results of surface-water, groundwater, and soil-pore gas monitoring during the fourth quarter 2007, and also summarizes the monitoring results obtained for the 2007 monitoring year. A summary of analytical results and time-series concentration plots for field and monitoring parameters are also included in this report. A description of field procedures and sampling protocols followed by personnel conducting field monitoring activities is included in Appendix B of the report. Groundwater quality conditions beneath the French Camp Landfill during the fourth quarter 2007 monitoring period are generally similar to those observed in previous monitoring periods. During the fourth quarter 2007 monitoring period, inorganic concentration limits (CLs) were exceeded in detection monitoring program wellsMW-8A, MW-9A, MW-913, and MW-10A, and with the exception of the chloride and potassium concentrations measured in well MW-10A, none of the constituents that exceeded a CL exhibited a significant increasing trend during the fourth quarter 2007 monitoring period. Previously, a no release demonstration concluded that French Camp Landfill, located within the central Stockton area, has been impacted by saltwater intrusion and the elevated chloride and potassium concentrations measured in well MW-l0A are believed to be the result of this condition and not the result of landfill-related impacts. Organic constituent results indicate trace concentrations of trichlorofluoromethane and 1,2- dichloroethane were measured in the samples collected from well MW-9A and MW-913, respectively, which are likely related to landfill gas generation following placement of the final cover system on the landfill. In a meeting with the RWQCB on March 9, 2007, Forward proposed quarterly monitoring of existing groundwater monitoring wells and soil-pore gas probes through May 2008 to evaluate the significance of landfill gas at the site. The results of water quality analyses completed for leachate monitoring well MW-2 indicates that no VOCs were detected in the sample from this well during the current monitoring period. i 16885 W. Bernardo Dr., Suite 305, San Diego, CA 92127 Phone: (858) 451-1136 Fax: (858) 451-1087