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<br />North County Recycling Center & Sanitary Landfill Department of Public Works/Solid Waste <br />First Semiannual 2025 Groundwater Monitoring Report ©2025 COUNTY of San Joaquin. All Rights Reserved <br /> 11 <br />5 MONITORING RESULTS <br />5.1 Groundwater <br />During the first semiannual period depth to water measurements were collected during First <br />Quarter on January 22, 2025, and Second Quarter on April 23, 2025. Samples are collected <br />semiannually and were collected beginning on January 22, 2025 for the wells that had sufficient <br />water. First Quarter 2025 data is provided on Table 3. Field data is provided in Appendix B and <br />laboratory analytical data is provided in Appendix C. <br />Due to dropping groundwater levels, samples for chemical analysis are no longer collected from <br />wells G-1A, G-2A, G-3D, G-4, G-5A, and G-6. The dropping groundwater conditions at the landfill <br />are due to over-pumping of regional aquifers for irrigation in the Central Valley. <br />5.1.1 Field and Monitoring Parameters <br />Field and general water quality parameters were within historical ranges during the 2025 first <br />semiannual period. A discussion of results with respect to established concentration limits <br />(CLs) is provided for each well sampled during first quarter. <br /> G-5B – This well was not sampled due to insufficient volume in the casing. <br /> G-7 – Field and general water quality parameters were below concentration limits. <br /> G-8 – Field and general water quality parameters were below concentration limits. <br /> G-9 – Field and general water quality parameters were below concentration limits. Due <br />to an issue with the pump, an incomplete sample was collected on January 23, 2025. <br />The rest of the samples were collected on January 29, 2025. <br /> G-10 – Field and general water quality parameters were below concentration limits. <br /> G-11 – Turbidity exceeded the CL during First Quarter 2025. <br /> G-12 – Bicarbonate exceeded the CL during First Quarter 2025. <br /> G-13 – Field and general water quality parameters were below concentration limits. <br /> G-14 – Field and general water quality parameters were below concentration limits. <br />5.1.2 VOCs <br />No VOCs were reported in any of the monitoring wells that surround the landfill during the 2025 <br />first semiannual period. <br />VOCs have not been detected above the laboratory reporting limits at the North County Sanitary <br />Landfill since 2008 when short-term detections were reported in wells G-3D and G-5A. Due to <br />the continued drop in groundwater levels at the site, neither of these wells have been sampled