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0 <br />New Historical Intrawell Maximum Values <br />As shown in the table below, seven new historical Intrawell maximum values were <br />measured during the second quarter 2008 monitoring event, generally representing only <br />slight increases form the previous historical intrawell maximum values. <br />New Historical Intrawell Maximum Values <br />Well <br />Analyte <br />New Value <br />Previous Value <br />MW -1 <br />Bicarbonate <br />760 mFZL <br />750 mEL <br />MW -10 <br />1, 1 -Dichloroethene <br />0.30j gg/L <br />0.28j gg/L <br />Trichlorofluoromethane 0.34j µg/L <br />0.32j gg/L <br />MW -14 <br />Ma esium <br />100 m L <br />98 m L <br />MW -16 <br />Chromium, Hexavalent <br />0.0091 m L <br />0.0067 m L <br />MW -24 <br />Sodium <br />62 m L <br />60m L <br />Sulfate 73 m L <br />70 maj <br />Notes: j — Trace Value between the (MDL and PQL). <br />Concentration Limit Thresholds <br />Data obtained during the second quarter 2008 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 second quarter 2008. As summarized in this table, CLs were exceeded <br />for wells MW-lA, MW -2A, MW -3, MW -10, M-13, MW -14, MW -15, MW -16, <br />MW -17, MW -18, MW -19, and MW -21. In accordance with the RPCMP, wells with CL <br />exceedances (other than arsenic, bicarbonate, hexavalent chromium, nitrate as nitrogen, <br />and sulfate, which the RPCMP do not consider impact constituents) will be resampled in <br />August during the third quarter 2008 sampling event and a second independent sample <br />will be collected in September 2008. The results of the retesting events will be submitted <br />to DTSC and RWQCB under separate cover. <br />2.1.5 Vadose Zone Monitoring <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 —6.5 to —25 inches of mercury on <br />May 8, 2008. On June 10, 2008, the lysimeters were again checked and positive pressure <br />was applied to evacuate the accumulated sample. As recorded in the field notes for <br />lysimeters (Appendix C) and summarized on Table 2-5, lysimeters W-2, LY -A, and <br />LY-BG1 had a sufficient volume of soil -pore liquid for sample collection. However, due <br />to the limited sample volumes, lysimeter samples were only analyzed for select inorganic <br />constituents and/or VOCs. As shown in Table 2-6, two VOCs (both above the PQL), <br />were measured in the lysimeter samples collected during the second quarter 2008 <br />monitoring period. <br />W2008_OO1 O\FA_2QO8.doc <br />6 Geologic Associates <br />