Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:3:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 3 (pt 2/9)
Character Range: 2879589–2882350

= 15kg for young children and 70 kg for adults
    ATNT = averaging time for non-threshold contaminants (days, = 70 years x 365 days) = 25 550 days

The calculated intake factor has taken into account age-adjustment factors that relate to the potential for exposures during childhood to be more sensitive than those later in life. This has been undertaken using the age adjustment factors (ADAF) outlined by US EPA (2005). The adjustment factors are as follows:
    * ADAF = 10 during the first 2 years of life
    * ADAF = 3 for ages 2 through to less than 16 years
    * ADAF = 1 for ages 16 through to 70 years.

The lifetime risk calculations undertaken for non-threshold compounds (based on the equations in this appendix) are based on exposures that occur as a young child aged 05 years, and then as an adult from ages 6 and older. The ADAFs have been applied within these calculations as follows:

     = 3.5x10-6 (kg/kg/day)

Based on the above the following is then calculated:

Calculation for Dermal Absorption from Soil/dust

Based on Equations 7 and 8, as well as the age-adjustment factors outlined by US EPA (2005), the HIdermal is calculated for BaP as follows:

Non-threshold contaminants (lifetime exposures)

            Equation 7

         Equation 8
where:

         TRVD  = toxicity reference value relevant for the quantification of dermal intakes, (as (mg/kg/day)-1 for non-threshold contaminants) = 0.5 (mg/kg/day)-1
         TR = target risk for non-threshold contaminants (unitless) = 1x10-5
         ∑ = signifies the sum over all receptor groups x considered (in the HILs derived, these groups include a child (C) and adult (A))
         SAx  = exposed skin surface area for all receptor groups x (cm2) = 2700 cm2 for young children and 6300 cm2 for adults
    AF = soil to skin adherence factor (mg/cm2/day) = 0.5 mg/cm2/day
    DAF = dermal absorption factor, (chemical-specific) (unitless) = 6% or 0.06 for BaP
    CF = conversion factor of 1x10-6 to convert mg to kg
         EFx = exposure frequency relevant to exposures by all receptor groups x (days/year) = 365 days per year for adults and children
         EDx = exposure duration relevant to exposures by all receptor groups x (years) = 6 years as child from 05 years and 29 years as adult aged 6 and older
    BWx = body weight relevant to each receptor group x (kg) = 15 kg for young children and 70 kg for adults
    ATNT = averaging time for non-threshold contaminants (days, = 70 years x 365 days) = 25 550 days

As noted above for the calculation of the soil ingestion HIL, age-adjustment factors have been incorporated into the calculation of the intake factor, with the calculations considered as follows:

     = 4.3x10-6 (kg/kg/day)

Based on