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DISCUSSION AND RECOMMENDATIONS <br /> Review of the monitoring data from start-up on January 5, 1990 to September 7, 1990, <br /> shows that 99+% of the contamination in the soils has been removed as expected <br /> within the areas of influence of the monitoring wells located between the pump island <br /> and the underground tanks. The concentrations of gasoline contaminants in the soil <br /> are much lower than initial readings and have progressively decreased confirming that <br /> vapor extraction is rapidly remediating the soil contamination. The dissolved <br /> groundwater contamination should already be partitioning off of the shallow <br /> groundwater Into the capillary fiinge of the vadose zone which explains the slower, rate <br /> of soil remediation for the last few months. By using the monitoring wells now as <br /> vapor inlet wells there will be a further improvement in the groundwater quality <br /> supporting an application for closure. <br /> VET recommends continued operation of the vapor extraction system through the end <br /> of 1990. During this time, new grounciw�Ater samples should analyzed to gauge the <br /> level of contamination left in the groundwater as the soils appear to be clean. If the <br /> concentrations In the water remain low, then Southiand should request to monitor the <br /> groundwater only and eliminate groundwater extraction and vapor extraction during <br /> the period of quarterly monitoring. Following a year of monitoring, VET recommends <br /> Southland to request closure of the site. <br /> 7 <br /> VAPOR EXTRACTION TECHNOLOGY, INC. <br />