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4 <br /> Steven Sasson -6- February 5, 1996 <br /> 1 California promulgated cancer slope factors (CSFs), as listed in the Cancer Potency <br /> Factors memorandum (Cal/EPA 1994), which is periodically updated, <br /> 2 CSFs, Reference Doses (RfDs), and Reference Concentrations (RfCs) developed by <br /> the USEPA and listed in the Integrated Risk Information Service (IRIS) (USEPA <br /> 1995a), and <br /> 3. Nonpromulgated USEPA CSFs, RfDs, and RfCs listed in the USEPA CSFs, RfDs, <br /> and RfCs listed in the USEPA Health Effects Assessment Summary Tables <br /> (FAST) (USEPA 1995b) <br /> No toxicity value was found for hydraulic fluid Hydraulic fluid is not considered as a carcinogen <br /> by the International Agency for Research on Cancer (IARC), the United States Environmental <br /> Protection Agency, or the California Environmental Protection Agency In the absence of a <br /> toxicity value for noncarcinogenic effects, the reference dose suggested by the Massachusetts <br /> Department of Environmental Protection (NIDEP 1994) for alkanes and cycloalkanes in the range <br /> of 19 carbons to 32 carbons was used This reference dose is 6 0 mg/kg/day (MDEP 1994) <br /> 2.1.5 Risk Characterization <br /> In the risk characterization, information from the exposure and dose-response assessments are <br /> combined to produce a quantitative estimate of risk Soil and air were the pathways evaluated in <br /> this assessment The appropriate equations from the PEA Guidance Manual (DTSC 1994) were <br /> used to calculate the potential hazard from these pathways As a conservative measure, the hazard <br /> index is calculated only for the first six years of childhood If the hazard index of 1 is not <br /> exceeded for the child, it will not be exceeded for any other age (DTSC 1994) <br /> The equations given in the PEA. Guidance Manual (DTSC 1994) are simplified USEPA hazard <br /> equations, which mcorporate and DTSC standard default exposure values (USEPA 1991, DTSC <br /> 1992) to achieve a reasonable maximum exposure for a residential setting As stated in the <br /> previous paragraph, the noncarcinogenic exposures are estimated for a child, which are the <br /> receptors with the greatest estimated exposures The equations used to calculate hazards from the <br /> soil and air pathways are presented below <br /> azard (soil) = ((Cs 1 RfDo) x (1 280 x 10-5)) + ((Cs l RfDo) x (1 28 x 10-5) x A <br /> Hazard (air) = (Ca l RfDi) x 0 0639 <br /> Where <br /> C. = Concentration in soil, mglkg (1600 mg/kg) <br /> C. = Concentration in air, mg/m3 (0 09 mg/m3) <br />