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ill � <br /> CAMBRIA <br /> benzene, and 13 ppmv MTBE A vapor sample collected at 12 01 contained 29 ppmv TPHg, <br /> <0 31 ppmv benzene, and 14 ppmv MTBE <br /> October 11, 2003 The extraction flow rate from SVE-3 ranged from 58 to 67 scfm and averaged <br /> 61 scfm over the course of the test, which ended at 12 01 on October 11 An approximate <br /> wellhead vacuum of 1 1 inches Hg was established with the liquid-ring pump set at a vacuum of <br /> approximately 20 inches Hg No vacuum influence was measurable in SVE-1 or SVE-2 <br /> A vapor sample collected at 12 01 contained 27 ppmv TPHg, <0 31 ppmv benzene, and 24 ppmv <br /> MTBE <br /> RESULTS <br /> Wells SVE-1, SVE-2, and SVE-3 were used to measure vacuum influence or alternately as <br /> extraction points Table 3 presents the vacuum radius of influence data and the effective radius <br /> of influence calculations The theoretical radius of influence is estimated according to the <br /> steady-state radial distribution equation in A Practical Approach to the Design, Operation, and <br /> Monitoring of In Situ Soil Venting Systems (P C Johnson, C C Stanley, M W Kemblowski, D L <br /> Byers, and J D Colthart, Groundwater Monitoring and Review, Spring 1990) An effective <br /> radius of influence is typically identified where observed vacuum is greater than or equal to 1% <br /> of the applied vacuum The theoretical radius of influence ranged between 18 6 and 19 9 feet <br /> Petroleum hydrocarbon and fuel oxygenate vapor concentrations were reported below or slightly <br /> above the laboratory reporting limits for all samples collected during SVE testing Based on <br /> operating parameters and vapor sample analytical results, the total TPHg, benzene, and MTBE <br /> vapor phase mass removed from the site as a result of SVE test activities is estimated at 2 68, <br /> 0 012, and 142 pounds, respectively <br /> CONCLUSIONS <br /> The magnitude and trend of petroleum hydrocarbon and fuel oxygenate vapor concentrations <br /> measured throughout the SVE testing indicates that there is insignificant impact to the source <br /> area This data suggests further source area remediation using SVE is not warranted Cambria <br /> will continue with the series of GWE events approved during our July 28, 2003 meeting and will <br /> submit a report with further conclusions following the final GWE event, scheduled for <br /> December 2003 <br /> • <br /> 0955 9 <br />