Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:3:p4
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 3 (pt 4/9)
Character Range: 1160484–1163503

that need to be protected. This requires the identification of local species, communities and ecological processes that are of ecological value based on the relevance and significance of societal, cultural, ecological, and economic factors.
    3. Exposure assessment characterises the site, identifies potential exposure pathways and estimates exposure duration, concentrations and intakes.
    4. Toxicity assessment involves estimating the concentration of contaminants at which species and ecological functions experience no harmful effects and those at which toxic effects are caused. This data is in turn used to determine the concentration of contaminants that an ecosystem can be exposed to without adverse effect or with adverse effects of a certain magnitude (that is, EILs).
    5. Risk characterisation involves combining data and information from the exposure and toxicity assessments to determine the risk that ecosystems at the site face from the contaminants. This is usually done by comparing the measured contaminant concentrations with the EILs.
The relationships between the five components are shown in Figure 2 below. Receptor identification, exposure assessment and toxicity assessment components are interrelated, as the assessment of any of these components is dependent upon the characteristics of the other two. Risk characterisation includes the combination of information gained in the exposure and toxicity assessments. The types and amount of information available to a risk assessor are always limited—whether it is information about the chemical levels at the site or the potential effects on an organism that a chemical could cause—so all ERAs are estimates of what the risks might be. Hence, it is important that the objectives (developed in the problem formulation stage) are re-set taking into account any additional information gleaned at every phase. Any assumptions or extrapolations made in an ERA should be highlighted where they occur. Uncertainty is discussed further in a later section of this Schedule.
Figure 2. Components of an ERA

The objectives and what is done in each component varies depending on whether the components are being conducted as part of a Preliminary ERA or a Definitive ERA.
A detailed discussion of what should be done in each component of Preliminary and Definitive ERAs is presented in later Sections of this Measure and examples on the application of EILs can be found in Schedule B1.

3.4              Risk management decision
At the conclusion of an ERA, a risk management decision needs to be made (as depicted in later discussions of Preliminary and Definitive ERAs). This decision is based on both the risk characterisation component of ERA and risk management considerations (such as economic, social, cultural and engineering matters) and should be made by the decision manager, in compliance with jurisdictional requirements.

This step ensures that both risk assessment and risk management considerations (including conflicting results