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In addition,the nitrate-nitrite(as N)has been below 10 mg/L since third quarter 2005. The present value is 0.05 ppm, whereas values were generally above 10 mg/L from third quarter 1995 to 2005. Prior to 1995, nitrate-nitrite was below 10 mg/L. The reduction in nitrate-nitrite since 2005 indicates a gradual return to previous levels. It is likely that the improvements made to the drainage conditions at the landfill in 2003 caused the improvements in general water quality at MW-4. No VOCs were reported at this well this quarter, and have not been reported in this well since July 26, 2001. MW-5 (Down-gradient, impacted): Concentrations of all parameters were within established concentration limits where the limits could be determined. The concentration limits of inorganic constituents are included in Table 1 to allow a comparison with the current data, although there may be significant trends present. The trend in Chloride and Total Dissolved Solids are increasing and the trend in Nitrate is decreasing. Six VOCs were reported this quarter, five above"trace" concentrations, none above 10 ppb (Table 1). No false positives occurred this quarter as they have in past quarters. VOCs were not found in any of the lab control samples this quarter. Trend analysis of VOC concentrations indicates increasing trends for two VOCs (Trichlorofluoromethane, and Tetrachloroethene) and a decreasing trend for Methylene Chloride. Trend analysis will continue to be used quarterly to evaluate concentrations of VOCs in MW-5. Deep Aquifer MW-6 (Down-gradient): Concentrations of all parameters were within established concentration limits where the limits could be determined (Table 2). No VOCs were reported at this well this quarter. Contamination(primarily toluene) was apparently introduced when this well was first installed in 2003,but quickly reduced to "trace" in three quarters. Excluding probable contamination at construction and compounds also found the QC blanks, no VOC has been reported in this well since October 2005. MW-7 (Up-gradient): Concentrations of all parameters were within established concentration limits where the limits could be determined (Table 2). Corral Hollow Landfill 8 Department of Public Works/Solid Waste 2nd Quarter 2007 Groundwater Monitoring County of San Joaquin—July 31,2007