Laserfiche WebLink
Ci <br />0 <br />C <br />�1 <br />0 <br />n <br />n <br />TDS <br />Chloride <br />Carbonate <br />Bicarbonate <br />Nitrate -Nitrogen <br />Sulfate <br />Statistical Analysis <br />Calcium <br />Magnesium <br />Potassium <br />Sodium <br />VOCs (Short List) <br />The NCRCSL has been approved to perform interwell tolerance limits (up -gradient well serves <br />as the background). Concentration limits are updated once yearly using interwell tolerance limit <br />methods, and were most recently updated for the second semester of 2005. Analytical results <br />from this monitoring event were compared to the concentration limits. <br />Concentration limits are updated where possible. If the historical data contains more than 50% <br />non -detects, the concentration limit cannot be updated. In these cases, the established <br />concentration limit listed in the WDRs is used for comparison. <br />A Rank Sum analysis is also performed if concentration limits cannot be updated. The Rank <br />Sum analysis determines if there is a significant difference between the median values of <br />historical and recent concentrations within a well. Concentration limits are updated on a yearly <br />basis in accordance with the latest WDRs. As requested by RWQCB staff, stiff diagrams will be <br />included in the second semester and annual report. <br />MONITORING RESULTS <br />Groundwater <br />Summary <br />Groundwater was sampled and analyzed July 21 and October 11, 2005. A trace of Acetone in <br />wells G-313, G-5, G-6 and a trace of Methylene Chloride in Well G-313 were reported in the third <br />quarter. A trace of Acetone in G-5 was reported in the fourth quarter. Both Acetone and <br />Methylene Chloride are common laboratory contaminants. Other than these five traces and <br />"false positives", no VOCs were reported this semester. <br />Field and Monitoring Parameters <br />Monitoring results for the third and fourth quarters (Tables 3 and 4) indicate that the <br />concentrations of field and monitoring parameters are below established concentration limits <br />with the following exceptions: <br />North County RCSL 6 Public Works/Solid Waste <br />2nd Semester and Annual 2005 Groundwater Monitoring County of San Joaquin — January 24, 2006 <br />