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S E C O R <br /> • 6.2.2 APSV Soil Vapor Concentrations <br /> Collected soil vapor sampling data is provided in Table 26 and shown on Figure 22. As shown <br /> on Table 26 and Figure 22, during the first quarter 2008 sampling event, TPHg was reported in <br /> soil vapor wells APSV-1, APSV-9, and APSV-10 at concentrations ranging from 39 parts per <br /> million by volume (ppmV) in APSV-1 to 269 ppmV in APSV-9. Methane was not detected in any <br /> soil vapor wells during the first quarter sampling event. <br /> 6.2.2.1 APSV Trends <br /> Collected soil vapor sampling data is provided in Table 26 and shown on Figure 22. As shown <br /> in Table 26, reported concentrations decreased for the following analytes in the following wells <br /> between the fourth quarter 2007 sampling event and first quarter 2008 sampling event: <br /> • APSV-1: TPHg, <br /> • APSV-3: TPHg <br /> • APSV-6: TPHg <br /> • APSV-9: TPHg, methane <br /> • APSV-10: TPHg, methane <br /> As shown in Table 26, reported concentrations increased for the following analytes in the <br /> following wells between the fourth quarter 2007 sampling event and first quarter 2008 sampling <br /> • event: <br /> • APSV-1: toluene <br /> • APSV-9: toluene, total xylenes <br /> • APSV-10: toluene, total xylenes <br /> During the first quarter 2008 concentrations of TPHg decreased in wells APSV-1, APSV-3, <br /> APSV-6, APSV-9, and APSV-10 in comparison to the fourth quarter 2007. Methane decreased <br /> in wells APSV-9 and APSV-10. Toluene was detected in well APSV-1 (0.06 ppmV) for the first <br /> time since sampling began. Concentrations of toluene were also detected in wells APSV-9 <br /> (0.06 ppmV) and APSV-10 (0.06 ppmV) for the first time since fourth quarter 2005 and second <br /> quarter 2006, respectively. Total xylenes were detected in wells APSV-9 and APSV-10 for the <br /> first time since second quarter 2007. <br /> 6.2.3 UPSV Soil Vapor Concentrations <br /> During the first quarter 2008, TPHg was reported in soil vapor wells UPSV-2 and UPSV-3 at <br /> concentrations ranging from 7 ppmV in soil vapor well UPSV-2 to 14 ppmV in soil vapor well <br /> UPSV-3. Methane was not reported during first quarter 2008. There have been no fuel <br /> oxygenates detected in UPSV wells since their installation. <br /> 6.2.3.1 UPSV Trends <br /> Collected soil vapor sampling data is provided in Table 26 and shown on Figure 22. As shown <br /> • in Table 26, reported concentrations decreased for the following analytes in the following wells <br /> between the fourth quarter 2007 sampling event and February 15, 2008: <br /> 1Q08QSSRQRSRQMR.Final.doc 30 April 30,2008 <br /> 77 TW.26397.42.1307 <br />