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SECTI ONF®UR APOSUM A38888MORR <br /> rational for the chosen scenarios is provided in Sections 4 2 As shown in the Conceptual Site Model <br /> (171gure 4-1), the complete exposure pathways evaluated quantitatively for this risk assessment are <br /> ingestion of groundwater from a well located 1,004 feet downgradient, inhalation of volatiles from soil <br /> and groundwater emissions, soil ingestion, and dermal exposures <br /> Potentially]Exposed Receptor Scenario Exposure Pathway <br />' Occupational Current/Future Inhalation of volatiles from soil <br /> Inhalation of volatiles from groundwater <br /> Soil ingestion <br /> Dernud exposure to soil <br /> Residential Adult/Child Future Groundwater ingestion from hypothetical well <br /> Inhalation of volatiles from soil and groundwater <br /> 4.4 ESTIMATING CHEMICAL INTAKES <br /> The next step in the exposure assessment was to quantify the magnitude, frequency, and duration of <br /> chemical intakes by receptor populations Tlus step was conducted in two stages (1) estimation of <br /> exposure point concentrations, and(2)estimation of chermcal intake for each exposure pathway under <br /> consideration Chenucal intakes were calculated using guidance in Risk Assessment Guidance for <br /> Superfund (EPA, 1989b), Exposure Factors Handbook (EPA, 1989x), DTSC Guidance (1993 and <br /> 1994), ASTM RB CA(1995), site-specific information, and professional judgment regardmg exposure <br /> conditions, as appropriate Chemical intakes were estimated using Reasonable Maximum Exposure <br /> (RUE) estimates of chemical concentrations in each scenano, and standard EPA and DTSC default <br /> values for exposure parameters such as body weight, inhalation and ingestion rates, and other <br /> assumptions regarding frequency and duration of exposure <br /> 4.4.9 Quantifying Reasonable Maximum Exposures (RIME) <br /> Intake of a chemical is generally described in units of milligrams(mg) of chemical per kilogram(kg) of <br /> body weight per day(mg/kg/day) The magnitude of exposure to a chemical(or intake)is a function of <br /> exposure point concentration and values that describe the exposed population (n e, contact rate, <br /> exposure frequency and duration,body weight, etc) <br /> For purposes of this assessment, only one measures of exposure was defined, namely the RME <br /> RME exposures were estimated in accordance with guidance provided in EPA's Risk Assessment <br /> T%IP97%73009NAW=KT0MREPORTSHORMV1DDCW-Fa14W273009NALSNA 4-5 <br />