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r Water Quality Monitoring Report Forward Landfill Historically, low-level concentrations of VOCs have been detected in the samples collected from the Forward Unit. On behalf of Forward Inc., GLA prepared a letter report dated February 14, 2001 (RWQCB Case No. 2209), to assess the source and potential impacts of low-level VOCs in groundwater adjacent to the Forward Landfill. The letter report concluded that the sporadic detection of low-level VOCs in groundwater (and lysimeter samples) at the Forward Unit are most likely due to landfill gas from unlined unit WMU-B. Concentration Limit Thresholds In accordance with RWQCB Order No. 115-2014-0006, the routine inorganic monitoring data obtained from the Forward Unit during the fourth quarter 2017 monitoring period were compared to intrawell concentration limits (CLs) established for each well. Updated CLs were calculated for the Forward Unit DMP. Details on the statistical analysis performed to determine the CLs presented in Table 2-4 are presented in Appendix G. As summarized in Table 2-4, the following CLs were exceeded during the third quarter 2017 monitoring period. • MW-15—bicarbonate • MW-18—total dissolved solids (TDS) • MW-19—barium, bicarbonate, chloride, magnesium, sodium, strontium • MW-21—nitrate as nitrogen (-N) In a letter dated January 30, 2018, the RWQCB was notified of these CL exceedances. All of the constituents exceeding a CL were place in "tracking mode" and are being evaluated quarterly for temporal trends(discussed below). Tracking Mode Constituent concentrations reported above a CL and confirmed in retest samples within the previous three years of monitoring were placed in "Tracking Mode" and are evaluated for temporal trends using Mann-Kendall trend analyses. The results of the trend analyses indicate that increasing 'trends were calculated for barium, bicarbonate, magnesium, potassium, and strontium at well MW-10; nitrate-N at well MW-15; chloroform and TCFM at well MW-17; and sodium at well MW-18 (Table 2-5). Mann-Kendall trend analyses calculations are presented in Appendix G. 2.1.5 Vadose Zone Monitoring The current vadose-zone monitoring network at the Forward Unit consists of 10 lysimeters (seven suction lysimeters and three pan lysimeters). These lysimeter locations are shown on Figure 2-1. As shown on Table 2-6A, samples were collected from suction lysimeters W-2 and LY-BG-1. The remaining lysimeters were reported dry during the monitoring period. As shown Project No.5017.1030 I Water Quality Monitoring Report 7 January 2018