Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:5:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 5 (pt 1/7)
Character Range: 1007777–1010900

5                   Toxicity assessment

5.1              Introduction
Toxicity assessment is typically divided into two activities:
    * hazard identification—the process of understanding the health effects of contaminants
    * doseresponse assessment—the process of making a quantitative link between the degree of exposure to a chemical and the effect realised.
These descriptors can have widely varying meanings, depending on the scope and purpose of the risk assessment. The sections herein describe the processes as they apply to assessing risks from contaminated land, with particular focus on site-specific decision-making.

Further and more general guidance on toxicity assessment is provided in enHealth (2012a).

Ideally, such assessments need to be undertaken by an appropriately qualified toxicologist. This is definitely required if any attempt is made to develop a TRV directly from toxicity data in the literature rather than use a TRV already developed by a government authority.

    5.1.1          Sources of toxicity information
Toxicity assessment in contaminated land risk assessment is primarily a literature-based research exercise. For contaminants which have an HIL, the findings of the literature review undertaken are presented in Schedule B7. In many risk assessments, reference to the appropriate review in Schedule B7 will provide adequate information to inform the toxicity assessment. In cases where no HIL is presented, or where the risk assessor is aware that more recent information is available, the toxicity review should be compiled and reviewed by an appropriately qualified toxicologist from reliable peer-reviewed sources.

In principle, risk assessments would ideally be based on research that has been carried out, peer reviewed and recommended by Australian health authorities as appropriate for Australian circumstances. In practice, there is limited Australian-specific information available, and Australian health standards for air quality and drinking water (for example, NEPC 2004, NHMRC 2011) are also largely based on international data sources, in particular, WHO publications.

There are a number of readily available web-based authoritative sources of toxicity information, which are designed for the purpose of informing risk assessments. In general, published Australian data and the classification of carcinogens as reported by the International Agency for Research on Cancer (IARC) should be used in risk assessments when available, but other data may be used where appropriately justified.

Data sources listed in Table 4 are considered to provide information that is compliant with Australian requirements for setting public health standards. They should generally be considered in the order listed in Table 4; however, it should be noted that the reliability of the data used in a risk assessment should not be based solely on the position of its source in the table. The most important consideration is that the data is supported by sound science and contemporary risk assessment methodologies, and that a weight-of-evidence approach has been used to assess