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Significant improvement in VOC concentration has been observed in well MW-2 with the non- detection of two chlorinated VOCs (CFC-12 and 1, 2-Dichloropropane) that indicated LFG impact. This is a significant improvement since 2007, when all three compounds were consistently reported at well MW-2. With the exception of Turbidity in MW-3, MW-4 and MW-5 no concentration limits were exceeded in any wells during the first semester 2013 sampling event where concentration limits could be determined. MW-1 (Up-gradient) No general water quality parameter concentration limits were exceeded this semester. Two VOCs (Benzene and Toluene) were detected in MW-1 at trace concentrations during the first sampling on February 1, 2013. Benzene and Toluene were also detected in trace concentrations during resampling on March 1, 2013. The consistent detection of VOCs in this well is unusual. The presence of VOCs in this well will be securitized during the next routine monitoring event. The trend analysis by Sanitas software indicates increasing trends for EC and Chloride, and a decreasing trend for Turbidity during the first semester 2013. However, MW-1 is the upgradient well. The increasing trends in EC and Chloride are unlikely to arise from the landfill, but could be from changes in background water quality conditions. MW-2 No general water quality parameter concentration limits were exceeded this semester. Three VOCs (Benzene, Toluene, and PCE) were detected in MW-2 at a trace concentration during the sampling on February 1, 2013. Benzene, Toluene and PCE were also detected in trace concentrations in resampling on March 1, 2013. Historically, the impact to groundwater at MW-2 was apparently due to landfill gas, as indicated by the presence of the following VOCs: • CFC-12 (last reported fourth quarter 2007) • 1,2-Dichloropropane (last reported in 2006) • PCE CFC-12 and 1,2-Dichloropropane were not detected in MW-2 during this sampling event, nor were they detected in MW-2 in the seventeen previous quarters. The lack of these compounds indicates removal of these VOCs from the groundwater at MW-2. Therefore, landfill gas extraction apparently has been successful in reducing or removing the VOC impact near this well. The consistence presence of Benzene and Toluene is unusual in this well, they will be securitized during the next routine monitoring event. The trend analysis by Sanitas software indicates increasing trends for Turbidity, TDS, Sulfate and a decreasing trend for Chloride during the first semester 2013 sampling event. The EC concentration in this well (335.7 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. Harney Lane Sanitary Landfill 6 Department of Public Works/Solid Waste 1 m Semester 2013 Groundwater Monitoring Report County of San Joaquin—July 15,2013