Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1:p4
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1 (pt 4/9)
Character Range: 2852404–2855387

= toxicity reference value relevant for the quantification of inhalation intakes, (as 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)
    PEFi,o = particulate emission factor (or dust loading) for outdoor (O) or indoor (I) air (m3/kg)
         ETci,co = exposure time outdoors (O) or indoors (I) for young child (for HILs A, B and C) and adult (HIL D) (hours/day)
    TF = indoor dust transport factor (unitless)
    RF = lung retention factor relevant for the inhalation of dust from site (unitless)
    EF = exposure frequency (days/year)
    EDC = exposure duration for young child (for HILs A, B and C) and adult (HIL D) (years)
    ATT = averaging time for threshold contaminants (hours, = ED x 365 days x 24 hours)

Non-threshold contaminants (lifetime exposures)

            Equation 10

  Equation 11
where:

         TRVi  = toxicity reference value relevant for the quantification of inhalation intakes, (as (mg/m3)-1 for non-threshold contaminants)
         TR = target risk for non-threshold contaminants (unitless)
         ∑ = 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)
    ETi,o = exposure time indoors (I) and outdoors (O) for adults and children (as relevant) (hours/day)
    TF = indoor dust transport factor (unitless)
    RF = lung retention factor relevant for the inhalation of dust from site (unitless)
    EFx = exposure frequency for all receptor groups x (days/year)
    EDx = exposure duration for all receptor groups x (years)
    ATNT = averaging time for non-threshold contaminants (hours, = 70 years x 365 days x 24 hours)

    1.3.4          Inhalation of volatiles
No soil HILs have been derived for volatile compounds, hence this section only presents the approach adopted in the derivation of interim soil vapour HILs.
For the derivation of soil vapour HILs, an attenuation factor has been adopted that relates the indoor air concentration to the soil vapour concentration.
The interim soil vapour HIL (based on indoor air exposures) has then been derived on the basis of the following equations:

Threshold contaminants (23-year-old child for HILs A, B and C and adult for HIL D)

      Equation 12

where:

         TRVi  = toxicity reference value relevant for the quantification of inhalation intakes, (as 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)
         α = soil vapour to indoor air attenuation factor (unitless)
    ETci = exposure time indoors (I) for young child (for