Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1:p10
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1 (pt 10/16)
Character Range: 2076649–2079477

one value in the range presented.

The derivation of a soil HIL requires the identification of an appropriate TRV, rather than a wide range of values, that is considered adequately protective of the population potentially exposed. The determination of an appropriate TRV for arsenic in soil in Australia has therefore considered the following:
    * The studies considered in the derivation of the different ranges of BMDL values (WHO 2011a and EFSA 2010) are based on drinking water studies. No studies considered are derived from other sources including soil. There are uncertainties inherent in the epidemiological studies considered by WHO (2011a) and EFSA (2010). These uncertainties include limitations or absence of information on levels of individual exposure or arsenic intake (from drinking water), limited quantification of arsenic intakes from other sources including food, size of the studies (variable) and the assumption that arsenic intake is the single cause of all  end points identified.
    * The drinking water studies are primarily associated with populations that have poorer nutritional status (i.e. Taiwan and Bangladesh). Studies (as summarised by EFSA 2010) have shown that populations with poor nutrition (and health status) are more susceptible to the prevalence and severity of arsenic-related health effects.
    * The largest of the studies conducted was within rural Asian populations, which differ from Australian populations with respect to generic lifestyle factors.
In view of the above, consideration of the lower end of the range of BMDL values available from WHO (2011a) and EFSA (2010) is not considered appropriate for the Australian population.

Based on the above considerations, a TRV of 2 µg/kg/day has been adopted in the derivation of a soil HIL. The TRV has been selected on the basis of the following:
    * The TRV is the lower end of the range derived from JECFA (WHO 2011a), and also lies within, but is not at the lower end of, the range presented by EFSA (2010).
    * The value is within the range of no observable adverse effect levels (NOAELs) identified by RIVM (2001), US EPA (US EPA 1998) and ATSDR (2007) that are associated with non-carcinogenic effects (and derived from drinking water studies in Taiwan and Bangladesh) of 0.88 µg/kg/day. Consistent with the approach discussed above in relation to the range of TRVs relevant to a cancer  end point, it is not considered appropriate that the most conservative end of this range is adopted for the Australian population.
Due to the level of uncertainty in relation to determining a single TRV for the assessment of arsenic exposures, the oral TRV used for the derivation of the soil HIL has not been considered to be a definitive value (refer to the calculations presented below). In addition, the approach adopted