Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:3:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 3 (pt 1/9)
Character Range: 1152404–1155458

3                   The ecological risk assessment framework
The methodology in Schedule B5b provides the means for deriving ecological investigation levels (EILs) used within the ERA framework. In developing the EIL derivation methodology, the approaches used by other entities (such as the USA, the Netherlands, Canada, the EU and the UK, Germany and New Zealand) were considered. A summary of these approaches is presented in an appendix of Schedule B5b.

This risk-based methodology incorporates the latest scientific findings in the areas of ecotoxicology, soil science and geochemistry. It enables:

    * protection of introduced and native animals, plants, microorganisms and microbial processes (including nutrient cycling)
    * setting levels of protection  based on land use
    * accounting for background concentration of contaminants
    * accounting for changes in bioavailability of contaminants over time and in different soils
    * accounting for contaminants that biomagnify.
The EILs are calculated using a species sensitivity distribution (SSD) method that permits the EILs to be set to protect any selected percentage of species (for example, for urban residential, it is 80%). They are derived based on the LOEC (lowest observed effect concentrations) and EC30 (30% effect concentration) toxicity data. Further information is provided below but full details of the EIL derivation methodology can be found in Schedule B5b and the derivation of the EILs can be found in Schedule B5c.  In addition, an EIL calculation spreadsheet can be found in the ASC NEPM Toolbox on the EPHC website, which provides step-by-step guidance on deriving EILs specific to the site, with consideration of certain physicochemical properties of soils.

The toxicity of some contaminants is affected by physicochemical properties of the soils in which the contaminant is located. When empirical relationships able to model the effect of soil properties on toxicity are established, then soil-specific EILs can be developed. The EILs take into account the biological availability of the element in different soils and separate naturally occurring concentrations of a contaminant and the added contaminant in deriving EILs which are based on the 'added risk approach' (Struijs et al. 1997; Crommentuijn et al. 1997). This approach assumes that the availability of the ambient background concentration (ABC) of a contaminant is zero or sufficiently close that it makes no practical difference. More importantly, it assumes that the background 'has resulted in the biodiversity of ecosystems or serves to fulfil the needs for micronutrients for the organisms in the environment' (Traas 2001). Therefore, the approach views only the effect of added contaminants to the environment as adverse (for further information refer to Section 2.4, Schedule B5b). Thus, rather than having a single numerical limit for a contaminant, different soils will have different limits. The EIL derivation methodology generates, wherever possible, soil-specific EILs. However, in