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No Impact. The gravelly sediment and distance to groundwater from the ground surface <br /> would be ideal for supporting a temporary septic tank or alternative disposal systems. If a <br /> septic system is considered for use, appropriate permits will be acquired in accordance <br /> with county requirements. <br /> Findings of Significance: <br /> ❑ Potentially Significant Impact <br /> ❑ Potentially Significant Unless Mitigated <br /> ❑ Less Than Significant Impact <br /> X No Impact <br /> 7. Hazards and Hazardous Materials <br /> Project activities likely to create an impact. <br /> e Removal of top 18 to 24 inches of burned material, ash and visibly affected soil within gravel <br /> pit area <br /> e Removal of localized areas of deeper soil containing elevated concentrations of metals or <br /> pyrolytic oil. <br /> • Transportation of contaminated materials to off-site disposal facility <br /> Description of Environmental Setting: <br /> Based on data from the preliminary site assessment, the soil has been impacted by contaminants <br /> related to the tire fire. Impact to soil appears to be limited to those areas where tires burned and <br /> primarily consists of elevated concentrations of metals. Contaminated soil and ash and other <br /> residual materials such as steel radials and solidified pyrolytic oil will be excavated and disposed <br /> to mitigate potential impacts to groundwater beneath the Site and to prevent potential impacts to <br /> human health. <br /> Groundwater data from the previous investigation documents that contaminants related to the tire <br /> fire may have impacted shallow groundwater at the Site. Concentrations of contaminants, <br /> primarily metals, are higher in downgradient and crossgradient site monitoring wells compared to <br /> concentrations in the upgradient site well. Quarterly groundwater monitoring will be conducted to <br /> better assess the groundwater quality at the Site. <br /> Description of Project Activities: <br /> This project will consist of excavation and transportation of contaminated soil to an off-site <br /> disposal facility. Excavated areas will be backfilled to the existing grade as appropriate. Potential <br /> risks associated with excavating and transporting soil will be minimized through operational <br /> control measures. For example, dust control will be implemented during excavation and material <br /> 29 <br />