R7 AM Soil Ecotoxicology and Risk Assessment
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in 327-329

(GIL-1117-758928) Multiple lines of evidence to assess metals in forested areas of Sudbury, Ontario.

Gilbertson, M-K¹, Hearne, K¹, Wren, C¹, ¹ C. Wren and Associates, Guelph, Ontario, Canada

ABSTRACT- The Ecological Risk Assessment (ERA) in Sudbury will evaluate the possible risk from airborne particulate emissions from the chemicals of concern (COCs) which are nickel, copper, cobalt, arsenic, lead and selenium. An area of uncertainty in the ERA is whether the soils in the Sudbury area are inhibiting the recovery of a self-sustaining forest ecosystem. Field and laboratory studies were conducted in 2004-2005 to determine whether the concentrations of the COCs present in the Sudbury soils pose an unacceptable risk to plants, invertebrates or microbial activity. This risk will be determined using a battery of single species terrestrial toxicity tests, field-based ecological measurements and soil chemistry. Soil toxicity testing methods are often used in the assessment of contaminated sites. Many of the existing tests are not designed for use in large forested areas in northern conditions. As a result, we have applied a battery of soil toxicity tests, including some experimental and some established methods. The results of the soil chemistry, toxicity testing and ecological characterization will be integrated to determine whether the concentrations of metals in the soil are inhibiting the recovery of a self-sustaining forest system. The approach that will be used to integrate the ecological information, soil chemistry and toxicity assessment will be presented and discussed. This information will address important data gaps that currently exist, and will significantly decrease the uncertainty associated with the final risk assessment.

Key words: metals, soils, risk assessment, toxicity testing