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f 0 <br /> obtained during this program 's definitional phase. Statistical <br /> evaluation of these data should yield a mutually acceptable <br /> definition of the range of "contaminant " values to be considered <br /> as native to the region. Marley is prepared to commit to soil <br /> contamination mitigation programs based upon such a mutually <br /> agreeable definition of native conditions. <br /> ( 2. In -Situ Soils Treatment. Marley acknowledges that a <br /> reservoir, of metallic contaminants exists in the vadose zone <br /> underlying the retort pit. Similar, but less concentrated <br /> contamination may also exist beneath the storm pond. Although <br /> the copper and arsenic contaminants appear to be geochemicaliy <br /> immobile , the chromium contamination may continue to migrate <br /> into the ground water resource over a period of years , even after <br /> cessation of imput of contamination to the system. It is <br /> possible to greatly shorten the period of such contribution by <br /> flushing the contamination from the v a d o s e zone into the <br /> saturated zone, followed by withdrawal and treatment as described <br /> above. It appears possible that such flushing could be achieved <br /> in the retort area by either placing fresh water within the <br /> retort pit and allowing the vertical migration to achieve plug- <br /> flow displacement of the contamination into the subsurface , or by <br /> drilling a series of shallow injection wells adjacent to the pit <br /> and allowing the imput water to displace the contaminated fluid <br /> into the subsurface. The efficacy of such treatment could be <br /> monitored by the pressure/ vacuum lysimeters to be installed in <br /> the area immediately adjacent to the retort pit. <br /> 25 <br />