Laserfiche WebLink
Foothill Sanitary Landfill 15 Department of Public Works/Solid Waste <br />First Semiannual 2025 Groundwater Monitoring ©2025 County of San Joaquin. All rights reserved. <br /> <br />o First Quarter – The CL for turbidity was exceeded and bicarbonate alkalinity was <br />at the CL, however, the concentrations remained within historical range. <br /> MW-3 <br />o First Quarter – Insufficient water was present to be sampled. <br /> MW-4A <br />o First Quarter – The CL for turbidity was exceeded and bicarbonate alkalinity was <br />at the CL, however, the concentrations remained within historical range. <br /> MW-5 <br />o First Quarter – Well MW-5 was reported as dry and could not be sampled. <br />Monitoring well MW-5 was last sampled during First Quarter 2020. <br /> MW-6 <br />o First Quarter – No CL’s were exceeded; all concentrations were within historical <br />ranges. <br /> MW-7 <br />o First Quarter – The CLs for turbidity, sodium, potassium, and sulfate were <br />exceeded. The concentrations of sodium and potassium were reported within <br />historical range. The concentrations of turbidity and sulfate exceeded the historical <br />maximums. <br /> MW-7R <br />o First Quarter – Insufficient water was present to be sampled. <br /> LW-1 <br />o First Quarter – pH is slightly lower than CL range. The CL for turbidity was <br />exceeded and bicarbonate alkalinity was at the CL, however, the concentrations <br />remained within historical range. <br />In general, most of these exceedances were only slightly over the limit. General water quality at <br />the site is good with relatively low dissolved constituents in groundwater. <br />6.2.2 Volatile Organic Compounds <br />VOCs were not detected in any of the groundwater monitoring wells during the first semiannual <br />2025 sampling events. <br />Well MW-3, which is discussed further below, was dry during First Quarter 2025. An attempt was <br />made to sample it again during Second Quarter 2025, however insufficient water was present to <br />sample the well. <br />VOCs have periodically been detected in MW-3. In response to detections of VOCs in well MW-3 <br />that started during the first semiannual 2011 sampling event, the County increased the corrective <br />action (LFG collection) to correct this situation. Improvements included the installation of