Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:3:p5
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 3 (pt 5/7)
Character Range: 2947075–2950083

lawns and facilities. Employees may make use of outdoor areas of a commercial/industrial premises for activities such as meal breaks. Opportunities for direct access to soil by employees using these facilities are likely to be minimal, but there may be potential for employees to inhale, ingest or come into direct dermal contact with dust particulates derived from the soil on the site. The CSM for this land use scenario is provided in Figure 4.

Figure 4. CSM for HIL D  commercial/industrial land use scenario

The derivation of soil HILs addresses all non-volatile compounds and exposure pathways. The interim soil vapour HILs for VOCCs address the vapour pathway only for these compounds.

    3.2.5         Sensitive populations

3.2.5.1         Overview
The HILs for each land use scenario have been developed to be protective of the majority of human populations that are sensitive to potential health risks from soil contamination. The HILs depend upon both the exposure scenario and the toxicity reference values selected for the contaminant.

The level of exposure of a given human population to health risks within a particular land use scenario is related to physiological factors (for example, children are often more heavily exposed to contaminants than adults because, in comparison to their body weight, they have higher rates of inhalation and ingestion and a larger skin surface area) and the frequency, extent and duration of exposure (for example, permanent residents are a more sensitive population than intermittent visitors).

The toxicity reference values were selected from collated peer-reviewed sources using the data sources described in Schedule B4.

Unless otherwise noted, all of these sources provide criteria that represent tolerable levels of exposure to the population inclusive of those individuals considered to be sensitive to the contaminant concerned. The toxicity criteria therefore inherently incorporate protection to sensitive populations. Different sources of toxicity criteria provide slightly differing approaches to protection of sensitive populations because they are derived by different bodies (for example, NHMRC, WHO and US EPA), which may have differing policy positions. The source and basis of selected toxicity reference values are presented on a compound-specific basis in Appendix A.

3.2.5.2         Residential and open space land use scenarios (HIL A, B and C)
The populations that are usually most sensitive to health risks associated with soil contamination in both low-density and high-density residential settings and in the open space scenario are young children aged 23 years. The characteristics of exposed populations applied in the development of the HILs have been derived in accordance with the recommendations outlined by enHealth (2012a). Young child residents and recreational users, while assessed on the basis of parameters relevant to 23 year old children, have been taken to be representative of children aged between 0 and