The Use of Speciation and Bioaccessibility Methods to Evaluate Contaminant Behaviour as part of Human Health Risk Assessment at Metal-Impacted Sites
C. Bacigalupo, G. Musca, E. Sigal,
Evaluating potential health risks related to exposures to metals in the environment pose a unique challenge, particularly in a mineral-rich area such as Sudbury, Ontario. Previous studies have highlighted key data gaps and assumptions imparting a high degree of uncertainty, thereby affecting the conservatism inherent in the risk estimates. However, as science and our understanding evolves, so does the “toolkit” available to a risk assessor to address these uncertainties. Two specific tools which aid in the evaluation of exposure and risk at metal-impacted sites are metal speciation (i.e., determination of the form, or species, of the metal in the environment and how this will impact its behaviour in terms of toxicology and environmental fate) and bioavailability/bioaccessibility (i.e., the fraction of total metal that is absorbed and distributed within biological organisms). Previous studies have shown that these two risk assessment components tend to have a substantial impact on risk estimates and related remedial costs. By addressing these areas of uncertainty, greater resolution can be brought to the actual health risks posed by these metals in the environment, and more appropriate risk management approaches can be developed to address any issues moving forward.
