Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:3:p3
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 3 (pt 3/9)
Character Range: 1157827–1160775

to soil down to a depth of two metres[1] below the current soil surface, which corresponds to the root zone and habitation zone of many species.

The tiered ERA approach used in this guideline permits:
    * identification of the ecological receptors of concern
    * estimation of the concentration of a contaminant of concern to which the ecological receptors are exposed
    * consideration of the toxicity-modifying or toxicity-enhancing capacity of the receiving  environment  (whether that be soil, sediment or water)
    * determination of whether the ecological receptors and ecological values may be at risk
    * application of a multiple-lines-of-evidence approach to assess risks.
This tiered approach relatively quickly and cheaply screens out those sites where the environmental risk is minimal. It thus focuses resources on those sites that pose the greatest potential risk. It should be emphasised that the majority of sites will only require a Preliminary ERA.

3.1              Preliminary ERA
Generally the first step in the ERA process is to decide whether a Preliminary ERA is necessary for the site in question. In some jurisdictions, at least some level of ERA is mandatory. Reasons for initiating a Preliminary ERA should be clearly stated in all ERA reports. ERAs are conducted using conservative assumptions (that is, they tend to favour protecting the environment). Thus, if a Preliminary ERA indicates the site faces a low risk from the contaminants, then there can be confidence that this is the case.

3.2              Definitive ERA
A Definitive ERA is required only in a situation where the concentration of the contaminant(s) is sufficiently high that it may pose a risk. A Definitive ERA requires greater data collection, uses more complex and environmentally realistic methods and reduces the uncertainty in the outcome of the ERA compared to the Preliminary ERA. As a result, Definitive ERAs are considerably more time-consuming and costly than ERAs.

3.3              Components of an ecological risk assessment
Both Preliminary and Definitive ERAs consist of the same five basic components:
    1. Problem identification is a scoping phase that establishes the objectives of the ERA and identifies the data required to achieve those objectives. It is essential that engagement with various stakeholders is undertaken early in this phase to provide opportunities for their input.
    2. Receptor identification focuses on 'what species may be at risk?' and 'what do we want to protect?'. Of importance in this phase is the need to introduce the concept of what is acceptable risk in the context of the ecological values 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,