Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:5:p5
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 5 (pt 5/5)
Character Range: 1201975–1203952

for each contaminant and the toxicity of the mixture of contaminants does not exceed the EILmixture (see Appendix 2), the site contamination is considered unlikely to pose an adverse ecological impact.

If the on-site soil concentration of any contaminant of concern is greater than the corresponding site-specific EIL or the toxicity of the mixture exceeds the EILmixture (see Appendix 2), the site contamination is considered to pose an adverse ecological impact.

5.6              Risk management decision and ERA outcomes
After risk characterisation, a risk management decision is necessary. If the risk characterisation suggests that there is unlikely to be an adverse impact to ecological values of the site (that is, on-site soil concentrations are equal to or less than the most appropriate site-specific EIL), the risk manager should decide between the 'no action' or 'monitoring' outcomes.

If the risk characterisation suggests that there may be an adverse impact to ecological values of the site (that is, on-site soil concentrations are greater than the most appropriate site-specific EIL), the risk manager should develop and implement a site management/remediation program.

Figure 4 above shows an arrow leading from the risk management decision back into the ERA process. This loop has been designed to allow for the further refinement of the characterisation of ecological risk. It uses a predictive approach based on monitoring undertaken as part, or as a result, of site management/remediation.

Expected outputs from a Definitive ERA include a report that extends the problem identification of the Preliminary ERA, provides detailed exposure and toxicity assessments for the contaminants as well as conclusions and recommendations. The report should detail the derivation of any modified site-specific EILs for the contaminants and describe the uncertainties in the field data (that is, contaminant levels and distribution) as well as in the modified EILs.