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Human Health Screening Evaluation <br /> Former Vernalis Pump Station September 2,2010 <br /> Oral and Dermal Hazards for Soil (PEA Guidance Manual, Figure 2.3): <br /> Hazardsoii= ([Cs/RfDo] x [1.28E-051) + ([Cs/RfDo] x [1.28E-04] x ABS) <br /> Where: <br /> Hazardsoii= oral and dermal non-cancer hazards from direct soil exposure <br /> Cs= concentration in soil, mg/kg <br /> RfDo =oral reference dose, mg/kg-day <br /> ABS =dermal absorption fraction, dimensionless <br /> The oral and dermal hazard calculations for potential exposure to on-site soils are provided in <br /> Table 13. SAIC-Benham estimated the potential non-cancer hazards for each COPC and then <br /> summed the hazards among chemicals for oral and dermal exposures. <br /> Inhalation Non-Cancer Hazard for Air(PEA Guidance Manual, Figure 2.4): <br /> Hazardair= (Ca/RfDi) x 0.639 <br /> Where: <br /> Hazardair= inhalation non-cancer hazard from indirect soil exposure <br /> RfDi=the inhalation reference dose, mg/kg-day <br /> Ca= concentration in air, mg/m3 <br /> Section 5.3 describes how SAIC-Benham estimated the value for Ca using equations presented in <br /> PEA Guidance Manual Figures 2.5, 2.6, and 2.7 for VOCs, and Figure 2.8 for non-VOCs. <br /> The inhalation hazard calculations for potential exposure to on-site soils are provided in <br /> Table 12. SAIC-Benham estimated the potential hazards for each COPC and then summed the <br /> hazards among chemicals for inhalation exposures. <br /> SAIC-Benham then summed the health hazards for oral and dermal exposures (Table 13)with <br /> the hazards for inhalation exposures (Table 14)to estimate the hazards across exposure routes for <br /> on-site soil. The sum of oral, dermal, and inhalation non-cancer hazards for on-site soil is <br /> provided in Table 15. <br /> 5.3 AIR CONCENTRATIONS OF ORGANIC COMPOUNDS FROM SOILS <br /> SAIC-Benham calculated the estimated air concentrations of non-VOCs (as wind-blown, <br /> suspended-soil particulates) and VOCs (following volatilization into ambient air)using equations <br /> provided by Cal/EPA in the PEA Guidance Manual. Those equations are provided in sections <br /> 5.3.1 and 5.3.2. <br /> 5.3.1 Air Concentrations of Non-Volatile Organic Compounds from Soil <br /> SAIC-Benham used the estimated ambient air concentration of non-VOCs as wind-blown, <br /> suspended-soil particulates to estimate inhalation exposures, and subsequently inhalation risks <br /> 8 �a The Benham Companies,LLC <br /> ,..frt j`® A Wholly Owned Subsidiary <br /> From S mxt to Solanoss <br />