IP02 Ecological Risk Assessment and Management of Smelters
B115 & B116
8:00 AM - 12:00 PM, Monday
(IP014) Risk Assessment to aquatic biota in the Columbia River from the Teck Cominco smelter at Trail, BC.
Swanson, S.M1, Ramesh, G1, Hamilton, T2, Duncan, W.F.A3, Hilts, S3, 1 Golder Associates Ltd., Calgary, Alberta, Canada2 Klohn Crippen, Vancouver, British Columbia, Canada3 Teck Cominco Metals Ltd., Trail, British Columbia, Canada
ABSTRACT- A two-tier aquatic risk assessment is being conducted to complement a parallel terrestrial ecological risk assessment of past, present and future emissions from the Teck Cominco smelter in Trail, BC. The first tier of the aquatic risk assessment provided the focus for the subsequent tier by ruling out risks from potential metals of concern to certain receptors via certain pathways of exposure in the Columbia River. The Tier I assessment revealed that most current and future risks are likely to be associated with the sediments. The Tier II assessment, now underway, is being conducted using a Weight of Evidence approach, with emphasis on field evidence for effects on periphyton, benthic invertebrates or fish health. Field studies are providing data in a spatial gradient from upstream to downstream of the smelter. The results of these field studies can be used to provide temporal evidence via comparison with studies conducted prior to upgrades of the smelter. The Weight of Evidence approach provides the framework for examination of the strength of causal relationships between water or sediment metal concentrations and observed responses in the field. This framework is important because of the presence of several confounding stressors such as hydroelectric dams, municipal outfalls and a pulp mill. The results of other studies conducted on the Columbia River will be used in conjunction with the data gathered in support of this risk assessment to assess the relative risk from the smelter-related metals of concern. The relative risk has likely declined, as a result of implementation of remedial works, including a significant reduction of air and effluent emissions from the smelter, and reduction of groundwater contaminant discharge to a tributary creek. The assessment of current relative risk will be used to evaluate the potential need for further remedial actions, and the potential benefits of such actions.
Key words: Metal contamination, Aquatic risk assessment, Relative risk, Weight of evidence