Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:2:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 2 (pt 1/4)
Character Range: 2867610–2870510

2                   Attachment A

2.1         Worked Example: Calculation of HIL A for cadmium

This attachment provides further detail on the calculation of the low-density residential (HIL A) calculation for cadmium based on the equations presented in this appendix, exposure assumptions presented in Table 5 of the main schedule and the information presented in Appendix A for cadmium. The calculations presented are also summarised in Appendix C.
Based on the information presented in Appendix A, the HIL for cadmium has been undertaken on the basis that it is a threshold contaminant, where the most sensitive receptor is a child aged 23 years. Hence only threshold calculations have been undertaken for this chemical, where the following assumptions have been used from Appendix A:

Calculation for Ingestion of Soil/dust

Based on Equation 3, the HILingestion is calculated for cadmium as follows:

      (mg/kg)
                   Equation 3
where:

         TRVo  = toxicity reference value relevant for the quantification of oral intakes, (as mg/kg/day for threshold contaminants) = 0.0008 mg/kg/day
         BIo  = background intakes relevant to oral/dermal exposures (from sources other than soil, which include food, water, air and consumer products where relevant) (% of the TRVo) = 60% for oral intakes
    IRSC  = ingestion rate of soil/dust by young child (mg/day) = 100 mg/day
    BAo = oral bioavailability (unitless, expressed as a fraction of 1) = 100% or 1 for cadmium
    CF = conversion factor of 1x10-6 to convert mg to kg
    EF = exposure frequency (days/year) = 365 days per year
    EDC = exposure duration for young child (years) = 6 years
    BWC = body weight of young child (kg) = 15 kg
    ATT = averaging time for threshold contaminants (days, = ED x 365 days) = 6 x 365 = 2190 days

Calculation for Dermal Absorption from Soil/dust

Based on information presented in Appendix A, dermal absorption of cadmium in soil in considered negligible and hence no calculation is required for this pathway.

Calculation for Inhalation of Dust
Based on Equation 9, the HILdust is calculated for cadmium as follows:

= 665 (mg/kg)
     Equation 9
where:
         TRVi  = toxicity reference value relevant for the quantification of inhalation intakes, (as mg/m3) = 0.000005 mg/m3
         BIi  = background intakes relevant to inhalation exposures (from sources other than soil, which include food, water, air and consumer products where relevant) (fraction relevant to the % allocated to background intakes) = 20% for inhalation intakes
         PEFi,o = particulate emission factor (or dust loading) for outdoor (O) or indoor (I) air (m3/kg) = calculated as below using Equations 19 to 21, PEFo = 3x1010 and PEFi = 2.6x107 (m3/kg)
         ETci,co = exposure time outdoors (O) or indoors (I) for young child (hours/day) = 4 hours/day outdoors and 20 hours per day indoors