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Concentration Limit Thresholds Data obtained during the first 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 first quarter 2010. As summarized in this table, CLs were exceeded for wells MW-10, MW-14,MW-19, and 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 May during the second quarter 2010 sampling event and a second independent sample will be collected in June 2009. The results of the retesting events will be submitted to DTSC and RWQCB under separate cover. As discussed above, 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 at the Forward Unit are most likely due to landfill gas from unlined unit WMU-B. Since low-level VOCs have been confirmed at the Forward Unit, retesting will be performed for inorganic constituents only from background well MW-22. 2.1.5 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—10 to—25 inches of water on March 24, 2010. On March 31, 2010, 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, all lysimeters were reported dry, and as a result,no soil-pore liquid samples were collected during the monitoring period. 2.1.6 Surface Water Monitoring Site run-on and run-off control facilities are designed to effectively channel surface water to site stormwater/sedimentation ponds. According to the Operations Manager, no surface water was discharged from the facility during the reporting quarter. During the first quarter 2010 monitoring period, no surface-water was observed at monitoring stations FSW-I and FSW-2, and as a result, surface water samples were not collected. 2.1.7 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 first quarter 2010, leachate was observed at all of the holding areas except WMU D-88 and D:U01 0001 3\FA-1 Q I O.doc 7 GeoLogic Associates