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Water Quality Monitoring Report <br />Forward Landfill <br />Concentration Limit Thresholds <br />In accordance with RWQCB Order No. 115-2014-0006, the routine inorganic monitoring data <br />obtained from the Forward Unit during the fourth quarter 2016 monitoring period were <br />compared to intrawell concentration limits (CLs) established for each well. Details on the <br />statistical analysis for the established CLs are presented in Appendix G of the fourth quarter <br />2014 Water Quality Monitoring Report for the Forward Landfill (GLA, 2014). As summarized in <br />Table 2-4, the following CLs were exceeded during the fourth quarter 2016 monitoring period. <br />MW -2A — chloride <br />• MW -10 — barium, calcium, magnesium, nitrate -N, potassium, sodium, strontium <br />• MW -13 — pH <br />• MW -15 — bicarbonate, nitrate <br />MW -17 — calcium, magnesium, potassium <br />• MW -18 — bicarbonate, calcium, magnesium, potassium, sodium <br />• MW -19 — calcium, potassium <br />MW -22 — bicarbonate, calcium, potassium, sodium <br />MW -24 —calcium, sodium <br />1191 In a letter dated January 19, 2017, the RWQCB was notified of these CL exceedances and <br />retesting is scheduled for January 2017. The results of the verification sampling will be <br />reported under separate cover. <br />v <br />Tracking Mode <br />Constituent concentrations reported above a CL and confirmed in retest samples within the <br />previous three years of monitoring were placed in "Tracking Mode" and are evaluated for <br />temporal trends using Mann -Kendall trend analyses. The results of the trend analyses indicate <br />that increasing trends were calculated for DIPS at well MW -16; carbon tetrachloride and <br />chloroform at well MW -17; and PCE at well AMW-12 (Table 2-5). Mann -Kendall trend analyses <br />calculations are presented in Appendix G. <br />2.1.5 Vadose Zone Monitoring <br />The current vadose-zone monitoring network at the Forward Unit consists of 10 lysimeters <br />(seven suction lysimeters and three pan lysimeters). These lysimeter locations are shown on <br />Figure 2-1. As shown on Table 2-6, pan lysimeters were reported dry and there was an <br />insufficient volume of soil -pore liquid (15 mL) for collection of samples from suction lysimeters. <br />Project No. 2016.0007 1 Water Quality Monitoring Report 8 <br />January 2017 <br />