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June 30, 1995 <br /> Page 10 <br /> PACIFIC is in concurrence that the chlorinated plume does not affect <br /> water quality goals regarding the hydrocarbon impact beneath the site. <br /> It is PACIFIC's opinion, however, that the chlorinated plume does <br /> affect the selection of a remedial alternative. <br /> 5. Specific tests should be performed on soils to determine the leachabil- <br /> ity of a compound not literature based evaluations. <br /> Given the lack of hydrocarbon-impacted soils beneath the site, field <br /> testing to determine the leachability of hydrocarbon impact in soils is <br /> not warranted. In addition, further hydrocarbon impact beneath the <br /> site does not appear to be threatened by the leaching or percolation of <br /> hydrocarbons from soil. This interpretation is based on the fact that <br /> the property is capped with an asphalt surface and hydrocarbon impact <br /> has not been identified within capillary fringe soils. <br /> 6. The Antidegradation Policy requires water quality goals to be <br /> between background and beneficial use protective goals; these are <br /> feasible at this site. There is no reason that the implementation of <br /> groundwater remediation will not achieve these goals. <br /> Evidence to date suggests that best available technologies alone will <br /> not achieve these goals. The primary reason for this is the variation in <br /> permeability for the soil types which underlie the site. For example, <br /> this contrast in permeability may lead to treatment of the higher <br /> permeability soils while the lower permeability soils are less treated. It <br /> has been shown, however, that given the course of time natural <br /> attenuation mechanisms will reduce these concentrations to acceptable <br /> concentrations. <br /> 4.0 REMEDIAL ACTION REQUIREMENTS <br /> I. Soil contamination threatens or impacts groundwater; these soils <br /> require remediation; the volume of contaminated soil should be esti- <br /> mated and the threat evaluated; more soil data is necessary to <br /> complete this task. <br /> Significant hydrocarbon impact to soils has not been documented (see <br /> Figure 4 of the CAP revision). The low dissolved hydrocarbon <br /> concentrations and the lack of hydrocarbon impact on capillary fringe <br /> 32013570C APLET.DOC.doc <br />