Research Activities

Risk Assessment Theme

Integration of MITHE-SN results into Environmental & Human Health Risk Assessments (E & HHRA) for metals are evolving in two ways, both of which are addressed by the research activities of MITHE-SN. First, risk assessments now typically include site-specific determinations for the protection of receptors of potential concern (ROPCs), as it is well recognized that generic guidelines for soils, water and air are poor fits for many environments. Site-specific considerations in RA, whether they involve metals in water, soil or air, must consider bioaccessibility (a measure of intrinsic availability) and bioavailability (a measure of the actual amount of metal entering an organism). Bioavailability and other site-specific considerations are a feature of MITHE-SN projects, which will develop tools that can be applied not only to the specific sites where the studies are conducted, but also more broadly throughout Canada and the world.

Second, metals risk assessments for specific locations are often labelled "Community Based" (CB). CBRA use the usual RA framework of problem formulation, exposure and effects assessment, and risk characterization. However, a CBRA implies that multiple properties are the subject of the risk assessment. It includes assessment of social risks, such as to property values, as well as enhanced involvement of, and communication with, the community of stakeholders. An example of how this influences risk assessment is where a generic soil quality guideline is set based on a human health endpoint, rather than on the basis of detrimental effects to a soil-dwelling organism or soil process. The application of such a SQG to soil metals in a remote region, where few humans reside, would anticipate a return to 'greenfield' (unrestricted use) conditions. A CBRA would recognize that this was not the relevant level of protection, and seek to establish a new, site specific SQG that protected the endpoints actually present in the community. This approach considers the apportionment of exposure of 'members' of the community among all the possible and reasonable pathways. Some, or all, aspects required to conduct CBRAs are a feature of the MITHE-SN Projects; they will be developing tools for furthering CBRA within Canada, which will also be applicable to other areas of the world.

The most important data gaps currently hindering the integration of exposure assessments for humans with exposure and effects assessments for ecological receptors, as identified by the attendees of the MITE-RN Kingston 2003 workshop , are the subject of our MITHE-SN program. While not a formal problem formulation exercise for specific metals, the Kingston workshop was attended by many of the same people who are involved in problem formulation for metals in soils, water and air.

The Network has recruited a team of three highly qualified and experienced risk assessors to supervise the integration of MITHE-SN's results into the framework for risk assessment: Dr. Evert Nieboer (McMaster University), Dr. Steve Sheppard (ECOMatters Inc.) and Dr. Peter Chapman (EVS Consultants Ltd.). These three individuals have combined expertise in risk assessment for human populations (Nieboer), terrestrial ecosystems (Sheppard) and aquatic ecosystems (Chapman). They will be responsible for continuous assessment of the MITHE-SN individual projects to ensure that their potential contribution to RA is fully realized. As well, they will also be responsible for ensuring that MITHE-SN addresses the risk assessment priorities of all of our partners within the context of a rapidly evolving scientific field.

E-mail Contact Information for Network ERA Consultants

Dr. Peter Chapman - Golder Associates Ltd.. North Vancouver, British Columbia (pmchapman@golder.com)
Dr. Evert Nieboer - Dept. of Biochemistry & Biomedical Science. Hamilton, Ontario (nieboere@mcmaster.ca)
Dr. Steve Sheppard - EcoMatters. Pinawa, Manitoba (sheppards@ecomatters.com)

Risk Assessment Contributions of MITHE-SN Projects (2007)

Notice

We are pleased to announce that a paper entitled, "Risk Assessment of Metals in the Environment", authored by Peter G.C. Campbell, Peter M. Chapman, and Beverley A. Hale (Contribution No. 48 from the Metals in the Environment Research Network) has been published in Issues in Environmental Science and Technology, No. 22, Chemicals in the Environment: Assessing and Managing Risk, The Royal Society of Chemistry, 2006.

Click here to view "Risk Assessment of Metals in the Environment".
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