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1 <br /> Treadwell&Rollo <br /> Soil and groundwater at Area 2A has been significantly impacted by petroleum fuel <br /> hydrocarbons, with evidence of off-site contamination. The extent of soil and groundwater <br /> ' contamination on the western and northern portion of the site is unknown. Calculated <br /> noncarcinogenic HIs exceeded 1 for construction and landscape maintenance workers, and <br /> residents. The excess cancer risk for residents exceeded 1 E-04, due to the presence of arsenic in <br /> the soil. <br /> Areas 213, 3, and 4 did not exhibit the degree of soil and groundwater contamination found at <br /> ' Area 2A. However, Area 3 arsenic concentrations in soil did result in calculated HIs exceeding <br /> 1.0 for residents, and excess cancer risks for residents exceeding 1.0E-6. Elevated total lead <br /> concentrations in soil at Area 3 may require that soil excavated at Area 3 are handled as a <br /> hazardous waste. Semi-volatile organic compounds at Areas 2B and 4 resulted in calculated <br /> excess cancer risks for residents, although the calculated risks were driven by relatively few <br /> occurrences of semi-volatile organic compounds. <br /> None of the soil and groundwater contamination found during this study should preclude <br /> redevelopment of the sites. However, the presence of soil and groundwater contamination will <br /> likely result in the requirement to use soil management plans for handling soil, and may impact <br /> ' some development alternatives, unless mitigation measures are taken. These measures may <br /> include spot excavation and removal of soil and the addition of vapor barriers to foundations. It <br /> ' is likely that additional site characterization will be required at Area 2A to fully define the extent <br /> and type of soil and groundwater contamination. <br /> 18 <br /> 25970119.DGD 13 December 1999 <br />