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• Occupational receptors were conservatively assumed to be exposed and <br /> working outside -.breathing potential site contaminants from volatile <br /> emissions for 8 hours/day. <br /> The exposure time outside for hypothetical adult and child residents was <br /> assumed to be 2.hours/day for the average case and 4 hours/day for the <br /> RME. F j <br /> Table 4-7 lists the intake assumptions for inhalation exposure to volatile emissions from <br /> soil for residents and occupational exposures. . <br /> 4.5.3 Assumptions for Ingestion of Groundwater <br /> Table 4-8 presents the specific variables used to estimate intake of chemicals via <br /> groundwater ingestion for the RME and average exposure scenarios for residential and <br /> occupational receptors. Ingestion rates for occupational employees and hypothetical <br /> residents were based on data presented for average and maximum intake rates in <br /> USEPA (1989). Adult residents and occupational employees were assumed to drink an <br /> average of 1.4 liters and a maximum upperbound of 2.0 liters of groundwater per day for <br /> the RME. Drinking water ingestion rate for child residents was assumed to be 1.0 liter <br /> of groundwater per day for both the average and RME (DISC 1994). <br /> 4.5.4 Assumptions for Exposure in Shower (Dermal"and Inhalation) <br /> The Kp values listed in the EPA Dermal Exposure Assessment Guidance (USEPA 1992) <br /> were used as permeability coefficients in the exposure calculation for adsorption of <br /> chemicals of potential concern in groundwater. . For potential dermal contact with <br /> groundwater, a shower scenario with whole body exposure was assumed. Since body s" <br /> weight has been shown to strongly correlate with surface area, RAGS (USEPA 1989) <br /> recommends the use of the ,average body surface area for dermal exposure to <br /> groundwater;during showering or bathing. These values were used for both RME and <br /> average exposures. The average body surface for adult males and females of 18,200 cm2 <br /> was used for occupational and adult residential receptors, and 8,000 cm2 was used for r-4 <br /> child residents. <br /> S:\LDC\YELLO.RPT May 4, 1995 4-17 �, <br />