Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:20:p2
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 20 (pt 2/3)
Character Range: 1342996–1345984

data for the SSD approach and at least one normalisation relationship (that is, relationships that describe the effects of soil characteristics on toxicity) is available.
Moderate reliability:
    * The toxicity database meets the minimum data requirements for the SSD approach but normalisation relationships are not available.
Low reliability
    * The toxicity database meets the minimum data requirements for the SSD approach but contains modelled toxicity data (that is, from QSARs, QAARs or the equilibrium partitioning method) or ecologically less relevant end points (e.g. biomarker end points).
or
    * The toxicity database meets the minimum data requirements for the AF approach.
In the Australian and NZ WQGs (ANZECC & ARMCANZ 2000), low reliability TVs were only used for interim guidance. A similar approach should be adopted regarding low reliability EILs—that such values should be considered to be a knowledge or data gap that requires further work to resolve.

For organic contaminants with low reliability EILs, the EILs are only as good as the QSARs and QAARs they were derived from. Therefore, further research is only necessary if the QSARs and QAARs are of relatively poor quality.

2.4.12     Evaluation of the appropriateness of the derived EILs
Once the EILs have been derived, their appropriateness should be evaluated. A similar process was also conducted as the last step in the derivation of the Australian and New Zealand WQGs (Warne 2001). Their appropriateness is determined by comparing each EIL with the toxicity data used to derive them, any available field-, mesocosm- or microcosm-based toxicity data, plant or crop nutritional requirements (for essential elements), and background concentrations. The aim of the comparison is to determine which species, if any, are likely to experience toxic effects if exposed to the EIL. If the species that potentially may be affected are considered rare or endangered, are keystone species, or are commercially important, then it may be appropriate to decrease the EIL (that is, increase the level of protection being provided). This evaluation or 'ground-truthing' process is, by necessity, done on a case-by-case basis.

2.4.13     Strengths and limitations of EIL derivation methodology
A discussion of the strengths and limitations of the methodology is presented below.

2.4.13.1     Strengths
The EIL derivation methodology:
    * is risk-based and enables protection of a selected percentage of species
    * incorporates assessment of all major exposure scenarios for terrestrial ecosystems, including secondary poisoning
    * can handle different types of toxicity data, thereby maximising the number of EILs that can be derived for contaminants
    * can be used to derive SQGs for a variety of different land uses and purposes
    * considers bioavailability and can therefore derive soil-specific EILs if the necessary data is available for the contaminant to ensure a uniform protection level for