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r. Sam <br /> C A 1V1 B R I A Mune 22,2001 <br /> Vacuum Influence: The maximum distance that vacuum influence was noted during the SVE <br /> testing was 80 ft in well MW-2 during the SVE test on well EW-1. The vacuum influence varied <br /> somewhat according to proximity of the vapor extraction well and monitoring points to the tank <br /> complex, which suggests some short-circuiting of vapor flow through the tank complex or other <br /> subsurface feature. <br /> Extracted Vapor Concentrations: The maximum concentration of hydrocarbons in extracted soil <br /> vapor in the field was 3 ppm near the end of the SVE test on well MW-1. The only hydrocarbon <br /> concentrations detected in vapor samples collected during the test were 3.87 ppm TPHg, and <br /> 0.408 ppm MTBE,both from MW-1. No hydrocarbons were detected in thee <br /> ffluent sample. <br /> CONCLUSIONS <br /> The SVE field tests demonstrated that there is not a significant amount of hydrocarbons <br /> remaining in soil above the groundwater table, even when the groundwater is depressed with <br /> groundwater extraction. A very small amount of hydrocarbons were detected in extracted soil <br /> vapor. <br /> The SVE field tests showed that vacuum influence from the SVE extended well into the areas <br /> most likely to have contained hydrocarbons — the area near the southeastern product island and <br /> the UST complex. The vacuum influence data showed that short-circuiting of vapors in the <br /> subsurface was most likely occurring to some extent. <br /> The ICE successfully provided adequate vacuum and flow to assess the presence of hydrocarbons <br /> and the adequacy of SVE for the site. The ICE was also successful at treating the extracted <br /> hdyrocarbons in soil vapor to non-detectable levels. <br /> Further vapor assessment and vapor extraction system installation are not recommended for this <br /> site. <br />• <br /> 0428 3 <br />