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New Historical Intrawell Maximum Values <br />No new historical intrawell maximum values were measured during the third quarter <br />2012 monitoring event. <br />Concentration Limit Thresholds <br />Data obtained during the third quarter 2012 monitoring period were compared to <br />concentration limits (CLs) as specified in the RPCMP for the Forward Landfill. CLs <br />were calculated by Herst & Associates and are included in Appendix D. Table 2-4 <br />summarizes CLs that were exceeded in samples collected from groundwater monitoring <br />wells during the third quarter 2012. As summarized in this table, one or more inorganic <br />CLs were exceeded at wells MW -2A, MW -3, MW -13, MW -14, MW -15, MW -18, and <br />MW -19. CL exceedances for non -impact constituents (arsenic, bicarbonate, hexavalent <br />chromium, nitrate as nitrogen, and sulfate) are not retested. In addition, CL exceedances <br />for low-level VOCs are not retested since similar low-level VOCs have been confirmed <br />at the Forward Unit. Therefore, only the following CL exceedances will require <br />retesting. <br />• MW -2A — calcium, chloride, and potassium <br />• MW-13—chloride <br />0 * MW -18 —calcium, magnesium, and sodium <br />E <br />The current vadose-zone monitoring network at the Forward Unit consists of 17 <br />lysimeters. The lysimeter locations are shown on Figure 2-1. Each accessible lysimeter <br />was inspected and vacuums were reset to approximately —25 inches of mercury on <br />August 17, 2012. On August 25, 2012, the lysimeters were again checked and positive <br />pressure was applied to evacuate the accumulated sample. As recorded in the field notes <br />for lysimeters (Appendix C) and summarized on Table 2-5, lysimeters were reported dry <br />to moist, and as a result, no soil -pore liquid samples were collected during the current <br />monitoring period. <br />Leachate Monitoring <br />Leachate sumps are inspected for the presence of leachate and observations are recorded <br />at least weekly by Forward Landfill personnel. If leachate is detected in a sump, it is <br />pumped into the surface impoundment (WMU F) for evaporation. During the third <br />quarter 2012, leachate was observed at all of the holding areas except WMU D-87 and <br />WMU D-88 AB. Freeboard at WW -F ranged from approximately 4.4 to 10.83 feet <br />during the third quarter 2012 monitoring period. Appendix A presents copies of the <br />leachate logs and the freeboard observation logs. <br />C:\2012-0025\FA3Ql2.doc 6 Geo -Logic Associates <br />