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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. 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 During the fourth quarter 2012 monitoring event, acetone (a common laboratory contaminant) was measured in the sample from well MW-10 (35 gg/L) exceeding the previous historical intrawell maximum concentration of 10 gg/L. Concentration Limit Thresholds Data obtained during the fourth quarter 2012 monitoring period were compared to concentration limits (CLs) calculated by Herst& Associates for the Forward Unit. CLs are summarized in Table 2-4 and included in Appendix D. As summarized in Table 2-4, one or more inorganic CLs were exceeded at wells MW-2A, MW-3, MW-10, MW-13, MW-14, and MW-15. Previously submitted No Release Demonstrations (NRDs) for common inorganic constituents at the site have concluded that the CL exceedances are not the result of a release from the Forward Unit. In addition, similar low-level VOCs have been confirmed at the Forward Unit and are not retested since similar low-level VOCs have been confirmed at the Forward Unit. Vadose Zone Monitoring The current vadose-zone monitoring network at the Forward Unit consists of 17 lysimeters. The lysimeter locations are shown on Figure 2-1. Each accessible lysimeter was inspected and vacuums were reset to approximately—25 inches of mercury on November 26, 2012. On November 28, 2012,the lysimeters were again checked and positive pressure was applied to evacuate the accumulated sample. As recorded in the field notes for lysimeters (Appendix C) and summarized on Table 2-5, lysimeters were reported dry to moist, and as a result, no soil-pore liquid samples could be collected during the current monitoring period. Leachate Monitoring Leachate sumps are inspected for the presence of leachate and observations are recorded at least weekly by Forward Landfill personnel. If leachate is detected in a sump, it is pumped into the surface impoundment (WMU F) for evaporation. During the fourth quarter 2012, leachate was observed at all of the holding areas except WMU D-87 and c:\zmz-0025\FAaQiz.aoe 6 Geo-Logic Associates