TP1 Sediment Quality Assessment Case Studies
256 Portland Ballroom
1:20 PM - 4:40 PM, Tuesday
() Ecological Risk Assessment of a Marine Foreshore in Prince Rupert, British Columbia.
Quaglia, S1, Clark, S1, Bryant, D1, Pimblett, B2, 1 Keystone Environmental Ltd., Burnaby, BC, Canada2 Canadian National Railway Company, Vancouver, BC, Canada
ABSTRACT- Historical industrialization and development in the past century has led to contamination of the marine environment of Prince Rupert Harbour on the North Coast of British Columbia. An ecological risk assessment (ERA) was conducted to determine the risks posed by contaminants originating from a large ocean dock used to store copper and lead-zinc ore that had been destroyed by fire during the early 1970s. Previous sediment investigations indicated that metals related to the ore were likely concentrated in the near-shore area in the vicinity of the spill but that some subtidal areas may also have been impacted. The ERA was structured using a weight-of-evidence approach in order to characterize the quality and area of the sediments affected by the ore spill. The results of a deterministic risk assessment were combined with a sediment quality 'quadrad' evaluation; an assessment of the impacts of contaminated sediment on aquatic life was based on four separate indicators of sediment quality (i.e. assessment of sediment chemistry, tissue chemistry, toxicity, and benthic community structure). A gradient approach was used determine the spatial distribution of risk to marine receptors. The study was also designed to qualitatively assess the potential effects of confounding factors, particularly a combined sewer outfall discharging effluent at the site. Preliminary results of the ERA indicate that the areas with a high probability of ecological effects related to site constituents of concern (COCs) are limited laterally and a moderate to high probability of effects may extend into the subtidal. This poster will summarize the approach, methods and results of the marine ERA.
Key words: sediment triad evaluation, Marine ecological risk assessment, confounding factors