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1 <br /> DISCUSSION <br /> Review of the vapor extraction system monitoring data from start-up on January 5, <br />' 1990 to January 29, 1991, shows that 98+% of the contamination in the soils has been <br /> remediated within the areas_of influence of the vapor extraction wells located between <br />' the um island and the underground tanks The extracted vapor concentrations of <br /> pump g <br />' gasoline have progressively decreased to the final steady state concentrations <br /> confirming that vapor extraction has rapidly remediated the site <br />' In conjunction with the extraction of vapor phase hydrocarbons in the soil, the <br />' dissolved groundwater contamination has partitioned off of the shallow groundwater <br /> 0 <br /> into the capillary fringe of the vadose zone as vapor No compounds, with less than <br /> fa 290° F bailing point, appear in the chromatograms of the extracted well vapors (see <br />' final chromatograms in Appendix ll for MW-1 and MW-4) This means all of the volatile <br /> TPH as gasoline and all BTEX has been removed from the soils and groundwater with <br /> only low volatility napthalenic compounds remaining <br /> The results of the most recent groundwater sampling show that very little groundwater <br />' contamination exists by total petroleum hydrocarbons as gasoline and no benzene, <br />' toluene, ethyl benzene, or xylenes were detected in any well, which supports the <br /> complete remediation of the soil and groundwater at the site <br />' VAPOR EXTRACTIOR TECHNOLOGY, INC <br />