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MONITORING RESULTS <br /> Groundwater <br /> Summary <br /> Groundwater was sampled on January 13, 2014 (Appendix A). <br /> No VOCs were reported in the deep aquifer wells. No VOCs were reported in shallow aquifer <br /> wells MW-4, MW-9A, and MW-10A this quarter. Data from the shallow aquifer wells beyond the <br /> County property seems to support a tentative conclusion that the quality of the water in this <br /> aquifer appears to be improving. <br /> Shallow Aquifer <br /> Summary <br /> Conditions in the shallow aquifer appear to be improving incrementally. <br /> No general water quality parameters were exceeded in any wells this quarter with the exception of <br /> Potassium in MW-5. <br /> Seven VOCs were detected in impacted on-site well MW-5 and five VOCs were detected in <br /> impacted on-site well MW-8 (compounds detected in"blank" samples not included). <br /> No VOCs related to landfillg as were detected in new off-site monitoring wells MW-9A and <br /> MW-10A this quarter. Six BTEX VOCs were detected at these wells when first monitored,but <br /> confirmation samples collected at these wells did not contain the BTEX. Initial BTEX <br /> observations were apparently due to lab error, as evidence by the non-detect results observed in <br /> the confirmation sampling. <br /> Four VOCs associated with landfill gas were detected in new off-site monitoring well MW-11A, <br /> all at trace concentrations. This could indicate an improvement because two of these compounds <br /> were previously repeatedly above the PQL. All VOCs detected in this well are among the VOCs <br /> found in MW-5 and MW-8, generally at lower concentrations. <br /> Data from MW-l0A and -11A is encouraging, with no landfill gas-associated compounds <br /> detected. This indicates an improvement in water quality at these wells. The County will review <br /> with interest succeeding monitoring data to assess whether we are seeing a continuing trend. <br /> The source of LFG-associated VOCs is apparently from LFG emanating from the refuse <br /> discovered near the County/Caltrans property boundary line, where the influence of the LFG <br /> system has been minimal. Landfill Gas System Information is provided in Appendix H. <br /> Corral Hollow Sanitary Landfill 12 Department of Public Works/Solid Waste <br /> 1 n Quarter 2014 Groundwater Monitoring County of San Joaquin-March 15,2014 <br />