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I ' 13 September 2002 . AGE-NC Project No 97-0290 ' Page 5 of 6 ' 34 SOIL VAPOR EXTRACTION A carbon-based SVE system operated during the quarter An additional carbon media change-out Iwas performed on 24 June 2002 Operational parameters are presented on Table 4 The hydrocarbon mass (TPH-g) removed during the operating period was calculated using the ' following equation M =C•Q•t where M =cumulative mass recovered (kg) ' C = soil-vapor concentration (kg/m') Q = extraction flow rate (m'/hr) t = operational period, in hours ' The operational time was divided into at least three time periods The calculated mass of hydrocarbons removed was based on laboratory analysis of soil-vapor samples The mass of rextracted hydrocarbons was calculated for each time period using average hydrocarbon concentrations of influent soil-vapor samples collected and average air flow rates Total of 165 '. gallons or 468 kg of gasoline (TPH-g and BTEX) were removed over the first three months of operation ' The volume/mass calculations are attached in Appendix D ' 35 IN-SITU AIR SPARGING Elevated concentrations of dissolved oxygen were detected in monitoring wells MW-4 and MW-5, ' which were used as observation wells outside the IAS network on the site Dissolved oxygen concentrations in the other, down gradient wells showed smaller changes A small change in dissolved oxygen was observed in well MW-2 samples within the sparging well network The ' dissolved oxygen data for each well measured is summarized in Table 5 ' 4.0. SUMMARY AND CONCLUSIONS Based on the data collected from the site, AGE finds ' Ground water was encountered in the monitoring wells at approximately 46 feet bsg and was ' inferred to have a southerly flow direction during the June 2002 monitoring event • The highest concentrations of dissolved petroleum hydrocarbons were detected in samples • collected from wells MW-2 and MW-4 ' Advanced GeoEnviron mental,Inc