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Water Quality Monitoring Report Forward Landfill exceeds its respective practical quantitation limit (PQL). During the third quarter 2017 monitoring period, non-statistical indications of a release were identified at well MW-2A as a result of trace concentrations of 1,1-dichloroethane (1,1-DCA), cis-l,2-dichloroethene (cis-1,2- DCE), and tetrachloroethene (PCE); MW-16 as a result of a quantifiable concentration of diisopropyl ether(DIPE); and at well MW-17 as a result of quantifiable concentrations of carbon tetrachloride, chloroform, and trichlorofluoromethane (TCFM) and trace concentrations of 1,1- DCA, dichlorodifluoromethane (DCDFM), PCE, and trichloroethene (TCE). In a letter dated October 17, 2017,the RWQCB was notified of the CNSDAM exceedances in wells MW-2A, MW- 16, and MW-17. Quantifiable VOC constituents were place in "tracking mode" and are being evaluated quarterly for temporal trends (discussed below). 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. R5-2014-0006, the routine inorganic monitoring data obtained from the Forward Unit during the third quarter 2017 monitoring period were compared to intrawell concentration limits (CLs) established for each well. Details on the statistical analysis for the established CLs are presented in Appendix G of the fourth quarter 2014 Water Quality Monitoring Report for the Forward Landfill (GLA, 2014). As summarized in Table 2-4,the following CLs were exceeded during the third quarter 2017 monitoring period. • MW-10—barium, bicarbonate, calcium, magnesium, nitrate-N, potassium, sodium, strontium • MW-15—nitrate-N • MW-17—sodium • MW-18—barium, bicarbonate, calcium,sodium, strontium • MW-19—bicarbonate, calcium, chloride, magnesium, potassium, sodium,strontium • MW-24—sodium In a letter dated October 17, 2017, 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). Project No.5017.1030 I Water Quality Monitoring Report 7 October 2017