Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:3:p3
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 3 (pt 3/9)
Character Range: 2882088–2884808

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 the above, the following is then calculated:

Calculation for Inhalation of Dust
Based on Equations 10 and 11, the HILdust is calculated for BaP as follows:

            Equation 10

  Equation 11

where:

         TRVi  = toxicity reference value relevant for the quantification of inhalation intakes, (as (mg/m3)-1 for non-threshold contaminants) = 0.14 (mg/m3)-1) (based on the TRVo and conversion based on inhalation of 20 m3/day and a body weight of 70 kg)
         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))
         PEFi,o = particulate emission factor (or dust loading) for outdoor (O) or indoor (I) air (m3/kg), calculated as outlined below
         ETi,o = exposure time indoors (I) and outdoors (O) for adults and children (as relevant) (hours/day) = 20 hours indoors and 4 hours outdoors for both young children and adults
    TF = indoor dust transport factor (unitless) = 0.5
    RF = lung retention factor relevant for the inhalation of dust from site (unitless) = 0.375
         EFx = exposure frequency for all receptor groups x (days/year) = 365 days per year for both young children and adults
         EDx = exposure duration for all receptor groups x (years) = 6 years as child from 05 years and 29 years as adult aged 6 and older
         ATNT = averaging time for non-threshold contaminants (hours, = 70 years x 365 days x 24 hours) = 613 200 hours

      Equation 19
where:

    PEFO  = particulate emission factor outdoors (mg/kg soil per mg/m3 air)
         Q/C  = air dispersion factor which describes the dispersion of soil particles in the atmosphere of a theoretical outdoor box. A value of 90.8 (g/m2/s per kg/m3) has been used in the derivation of HILs. The value is a default value recommended by US EPA (2002) for small sites (0.5 acres).
    V  = the fraction of outdoor surface cover (0= bare soil), (unitless) = 0.75
         Um  = mean annual wind speed at a height of 10m (m/s), assumed to be 8.75 km/hr (or 2.4 m/s) based on the average 9 am and 3 pm winds from Canberra
         Ut  = threshold value of wind speed at a height of 10m (m/s), which is how much wind is required to generate dust at a given site from an erodible surface. A default value of 7.2 m/s has been used in the derivation of HILs (EA 2009)
         Fx  = empirical function