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control structures effectively directed stormwater from the waste material during the first quarter 2010. 2.0 Groundwater Monitoring Program During the first quarter 2010 monitoring event, groundwater monitoring was performed at the French Camp Landfill by Del-Tech. Groundwater samples were collected from two background monitoring wells (MW-6A and MW-7A) and four detection monitoring wells(MW-8A, MW-9A, MW-913, and MW-10A) during the first quarter 210 monitoring event. The analytical results from samples collected at these wells are used to determine potential landfill-related impacts. During the first quarter 2010 monitoring event, analysis for field parameters (pH, specific conductance, temperature, and turbidity) and monitoring parameters (bicarbonate, calcium, carbonate, chloride, magnesium, nitrate, potassium, sodium, sulfate, total dissolved solids [TDS], and volatile organic compounds [VOCs]) was performed for the background monitoring wells and detection monitoring wells. The field results provided by Del-Tech and the laboratory results provided by BC Laboratories, Inc. (BC Labs) for the first quarter 2010 groundwater monitoring event are summarized on Table 2.2. The historical groundwater data for the background and detection monitoring wells are presented in Appendix D. Times series concentration plots of historical groundwater data for the monitoring wells are presented in Appendix E. For VOCs, only those compounds that exhibited detections at groundwater monitoring wells during the first quarter 2010 monitoring event were plotted. The concentration limits presented on Table 2.2 were calculated by Herst & Associates, Inc. from data collected through the first quarter 2010 monitoring event. The statistical analysis calculations for groundwater monitoring wells are presented in Appendix E. A copy of the statistical analysis methodology is presented in Appendix C. As presented on Table 2.2, the following constituents exceeded their respective concentration limits during the first quarter 2010: calcium at MW-9A and MW-913; chloride at MW-9B; potassium at MW-9A and MW-913; and field temperature at MW-8A, MW-9A, MW-913, and MW-10A. Elevated chloride concentrations (with elevated specific conductance values) could indicate a saltwater intrusion to the groundwater. The French Camp Landfill is within the central Stockton area impacted by saltwater intrusion (Fourth Quarter/Annual 1999 Monitoring Report, French Camp Landfill, CH2M HILL,January 2000). Historical data from the groundwater monitoring wells were analyzed for temporal trends using Mann-Kendall / Sen's Slope trend analysis. Graphs and summary tables of the Mann-Kendall / Sen's Slope analyses for groundwater monitoring wells are presented in Appendix E. Chloride at MW-10A, potassium at MW-913, and sulfate at MW-913 exhibited increasing trends. Of these constituents, only potassium at MW-9B exceeded its concentration limit. Mann-Kendall / Sen's Slope analysis identified decreasing trends in the following constituents: bicarbonate alkalinity at MW-8A, calcium at MW-6A and MW-8A, chloride at MW-7A, magnesium at MW- 6A and MW-8A, nitrate at MW-8A and MW-10A, field pH at MW-6A and MW-913, sodium at MW-8A, field specific conductance at MW-7A, sulfate at MW-7A,total dissolved solids at MW- 7A, and field turbidity at MW-7A, MW-9A, and MW-10A. As noted above, MW-6A and MW- 7A are background monitoring wells, and trends in the groundwater quality at these wells are not indicative of an impact from the facility. Potassium at MW-913 is the only constituent that exceeded its concentration limit and also exhibited a significant increasing statistical trend. The first quarter 2010 concentration of