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DISCUSSION <br /> • At the time of the fourth quarter 2004 monitoring event, groundwater elevations had increased between <br /> 0 31 and 0 49 feet in wells MW-13, MW-14, and decreased 135 feet in well AS-1 since the previous <br /> monitoring event (September 7, 2004) Groundwater in wells MW-13, MW-14, and AS-1 are fluctuating <br /> within historical ranges Wells MW-1 and VW were dry, consistent with historical data <br /> TPHG (2,600 ltg/L), benzene (2 7 gg/L), and MTBE (2 4 [ig1L) were reported in well MW-13 TPHG was <br /> also reported in wells MW-14 (370 µg/L) and AS-1 (180 pg/L) 1,2-DCA was reported in wells MW-14 (15 <br /> gg/L) and AS-1 (7 3 gg/L) TBA, DIPS, ETBE, TAME, or EDB were not reported in any of the wells <br /> Concentrations of hydrocarbons reported in wells are generally consistent with historical data <br /> Bio-Venting <br /> Bio-venting activities were initiated on November 16, 2004 An oil-less compressor is utilized to pump air <br /> into wells MW-13, MW-14, and AS-1 In wells MW-13 and MW-14, the air is delivered via drop tubes <br /> installed to approximately 1 foot above the bottom of the well In well AS-1, the air is applied directly to the <br /> well casing, as in conventional sparging The air is delivered to the wells via subsurface conveyance <br /> piping During the fourth quarter, airflow ranged from 60 to 65 liters per hour at pressures of 24 to 29 <br /> pounds per square inch <br /> ATTACHMENTS <br /> • Table 1 Groundwater Elevation and Analytical Summary <br /> • Figure 1 Site Location Map <br /> • Figure 2 Site Map <br /> • Appendix A Field Data Sheets <br /> • Appendix B Sampling and Analysis Procedures <br /> • Appendix C Certified Analytical Reports and Chain-of-Custody Documentation <br /> K 1TeichertlStockton-1031Quarterly120041Tcichert4Q04 DOC 5TRAW:5 <br />