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MOITOI SULTS Groundwater ISummary Groundwater was sampled on May 2, 2014 (Appendix A). No VOCs were reported in the deep aquifer wells. No VOCs were reported in shallow aquifer wells S13-1, MW-4, MW-9A, or MW-10A this quarter. Data from the shallow aquifer wells beyond the County property continues to support a tentative conclusion that the quality of the water in this aquifer appears to be improving. Shallow Aquifer Summary Conditions in the shallow aquifer appear to be improving incrementally. No general water quality parameters were exceeded in any wells this quarter with the exception of turbidity in MW-8. Ten VOCs were detected in impacted on-site well MW-5 and six VOCs were detected in impacted on-site well MW-8 (compounds detected in"blank" samples not included). Results at these wells are consistent with previous monitoring results. No VOCs related to landfill gas were detected in new off-site monitoring wells MW-9A and MW-l0A this quarter. Three VOCs associated with landfill gas were detected in new off-site monitoring well MW-11 A, all at trace concentrations. This could indicate an improvement because one of these compounds was previously repeatedly above the PQL. All VOCs detected in this well are among the VOCs found in MW-5 and MW-8, generally at lower concentrations. Data from MW-9A and-10A is encouraging, with no landfill gas-associated compounds detected. This indicates an improvement in water quality at these wells. The County will review with interest succeeding monitoring data to assess whether we are seeing a continuing trend. The source of LFG-associated VOCs is apparently from LFG emanating from the refuse discovered near the County/Caltrans property boundary line, where the influence of the LFG system has been minimal. Landfill Gas System Information is provided in Appendix H. Corral Hollow Sanitary Landfill 13 Department of Public Works/Solid Waste 2od Quarter 2014 Groundwater Monitoring County of San Joaquin—July 15,2014