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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. The particular VOCs detected in samples during the current monitoring period appear to support this conclusion. Forward has continued to minimize gas related impacts to groundwater by limiting interim fill areas that promote ponding of water. Furthermore, in accordance with CCR Title 27, Section 20937, Forward continues to install additional landfill gas extraction wells, as needed. New Historical Intrawell Maximum Values As shown in the table below, five new historical intrawell maximum values were measured during the third quarter 2010 monitoring event. New Historical Intrawell Maximum Values Well Analyte New Value Previous Value MW-3 Barium 0.253 m L 0.25 m L MW-13 Sulfate 64.1 m L 52 m L MW-18 Sulfate 90.4 m L 83 m L MW-19 Acetone 58 µg/L 45 gL MW-22 I Chromium,Hexavalent 1 0.0086 L 0.0056 g/L Concentration Limit Thresholds Data obtained during the third quarter 2010 monitoring period were compared to concentration limits (CLs) as specified in the RPCMP for the Forward Landfill. CLs were calculated by Herst &Associates and are included in Appendix D. Table 2-4 summarizes CLs that were exceeded in samples collected from groundwater monitoring wells during the third quarter 2010. As summarized in this table, CLs were exceeded for total dissolved solids (TDS) at well MW-3; sulfate at wells MW-10, 13, 15, and 18; barium, chloride, and sulfate at well MW-21; and hexavalent chromium and sulfate at background well MW-22. In accordance with the RPCMP, wells with CL exceedances of impact constituents (as defined in Table 5-3 of the RPCMP) will be resampled in November during the fourth quarter 2010 sampling event and a second independent sample will be collected in December 2010. The results of the retesting events will be submitted to DTSC and RWQCB under separate cover. Of note, CL exceedances for non-impact constituents (arsenic, bicarbonate, hexavalent chromium, nitrate as nitrogen, and sulfate) are not retested, and therefore, retesting for sulfate and hexavalent chromium is not required. In addition, CL exceedances for low-level VOCs are not retested since similar low-level VOCs have been confirmed at the Forward Unit. D:\?0 t 0_00 t 3\FA_3Q t 0.doc 6