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Problem Identification - Tiers 2 & 3

Ecotoxicity testing protocols 

Ecotoxicity results

Contaminant mobility

Soil property data

Models

Toxicity databases

RA methodologies

Document resources

 

Problem Identification

Receptor Characterisation

Exposure Assessment

Toxicity Assessment

Risk Characterisation

Tier 2 – Problem Identification

At this level of investigation, Problem Identification will retain the same primary features of Tier 1.

Tier 2 Problem Identification should summarise the state of information regarding the site, contaminants, potential receptors, pathways, and effects based on the information obtained previously. At this point, the conceptual model developed during Tier 1 should be modified and refined to take into account the Tier 1 information showing aspects that are not likely to be significant (and are therefore excluded from further investigation) and those that are potentially significant.

Tier 2 Problem Identification is likely to include objectives for the following:

  • identification of contaminants of concern including the chemical properties of contaminants exceeding the benchmark criteria (as determined in Tier 1 RA),
  • determination of the degree and extent of site contamination,
  • evaluation of the parameters affecting toxicity (e.g. pH, hardness) and exposure, and
  • development of modified human health or ecotoxicological criteria.

At this point in the process, additional site investigations may be required to further define the extent and degree of contamination, the characteristics of potentially affected receptors and habitats, and refine understanding of the site conditions affecting contaminant toxicity and mobility. The focus of site investigations will depend on the objectives for the Tier 2 RA, and on the quality and breadth of information obtained during the previous site investigations.

This link takes you to an example to demonstrate what is required at this level in the ERA. An example of a refined concept plan for XYZ Enterprises site is provided.   

Tier 3 – Problem Identification

Tier 3 Problem Identification should summarise the state of information regarding the site, contaminants, potential receptors, pathways, and effects based on the information obtained previously. At this point, the conceptual model modified and refined during Tier 2 should be further refined to take into account the additional information collected.

The Tier 3 Problem Identification is likely to include a definition of objectives for the following:

  • identification of contaminants of concern including the properties of each chemical form and mixtures for contaminants exceeding modified ecotoxicological criteria (as determined in Tier 2 RA),
  • modelling predictions about current and future risks to site-specific ecological values or human receptors,
  • evaluation of the refined parameters affecting toxicity and exposure assessments,
  • determination of the modified criteria.

At this point in the process, further site investigations may need to be undertaken to fully define the characteristics of potentially affected populations for species of concern, and refine understanding of the site conditions affecting contaminant toxicity and mobility. Other information that could be required may include:

  • biological surveys of receptor characteristics,
  • behavioural analyses,
  • habitat surveys,
  • sampling of receptor tissue or body fluids, and
  • laboratory studies of toxicity and exposure to a contaminants.

This link takes you to an example to demonstrate what is required at this level in the ERA. Follow this link for the XYZ Enterprises example.   

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Page last updated: 01 May 2007

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