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® CFC-12 and 1,2-Dichlopropane were not detected in MW-2 during this year. PCE was detected in concentrations below 1 ppb. The reduction of impact indicates significant reduction in impact by VOCs at MW-2. The trend analysis by Sanitas software indicates increasing trends for Turbidity, TDS, and a decreasing trend for Chloride during the first and second semester 2012 Sampling Events. The EC concentration in this well (360 mg/L) is far below the secondary maximum contaminant level (MCL) of 900 uS/cm , and indicates good water quality. TDS has also not exceeded their secondary MCL standards, which address aesthetics rather than human health issues. It is unlikely that the increasing trend in turbidity is a result of landfill activities. Siltation within the well is often the cause of an increase in turbidity that does not affect the water quality of the aquifer outside of the well. As such, turbidity is an indicator of well function and not an indicator of landfill impact to groundwater. MW-3: Groundwater samples were not collected from MW-3 during the second semester 2012 sampling event conducted on July 30, 2012 due to a lack of water required for analysis. Samples will be collected during the next sampling event if enough water is present for collection. No general water quality parameters were exceeded in MW-3 during the first semester 2012, with the exception of turbidity, which was exceeded during the first semester 2012 sampling event. Increasing trends in turbidity and total dissolved solids were noted during the first semester. The ® increase in turbidity could be due to siltation within the well that does not affect water quality of the aquifer outside of the well. As such, turbidity is an indicator of well function and not an indicator of landfill impact to groundwater. Decreasing trends in chloride were observed in MW-3 during the first semester. Two VOCs (Benzene and Toluene) were detected during the first semester 2012 sampling event. Toluene has historically been present in MW-3, so the Toluene observation during the first semester 2012 sampling event is not considered a new release. The presence of VOCs will continue to be checked for at this well during the next semiannual event. MW-4: No general water quality parameter concentration limits were exceeded in MW-4 during the first or second semester 2012 sampling events, with the exception of turbidity. An increasing trend in turbidity, pH, and TDS were observed during the first and second semester 2012 sampling events. A decreasing trend was observed for Chloride during the first and second semester 2012. No VOCs were detected during the first semester 2012 sampling event. One VOC (Acetone) was reported in MW-4 during the second semester 2012 sampling event. Prior to the second semester 2012 sampling event, VOCs were last reported during the second semester 2009 monitoring event.. Prior to the 2009 VOC detections, VOCs were last reported in this well in second semester 1999. The presence of VOCs will continue to be checked for in this well during the next semiannual event. Harney Lane Sanitary Landfill 11 Department of Public Works/Solid Waste 2nd Semester and Annual 2012 Groundwater Monitoring Report County of San Joaquin—January 25,2013