7.1    Atmospheric deposition of contaminants to the Athabasca Oil Sands Region

Jeff Brook and Jane Kirk, Environment Canada





Monitoring for toxic compounds such as polycyclic aromatic compounds (PACs), trace metals and mercury has been established in the Athabasca Oil Sands Region (AOSR) to determine their atmospheric fate, including transport, transformation, and deposition. We present results from measurements at sites within and outside the major mining development areas including: (1) air and precipitation measurements at 3 locations; (2) integrated passive sampling at 17 locations; (3) snowpack sampling at ~130 sites; and (4) analysis of 19 lake sediment cores to examine long-term (~100 years) trends in contaminant deposition. In addition, an approach to estimating dry deposition from observed air concentrations will be described. Air measurements show that concentrations of PACs and metals decrease with distance from the main surface mining and upgrading activities, that alkylated-PACs are more abundant than the unsubstituted PACs, and that crustal elements, such as iron, silicon, aluminum, and calcium, are some of the most elevated of the metals. Snowpack loadings of PACs and metals decrease with distance from the major developments, with the highest deposition occurring within 50 km of the main development area. Dated lake sediment cores suggest that PACs deposition is 1-19 times higher in recent decades (post-1990s) than before development began (pre-1960s) in lakes located within 50 km from major developments. Next steps include integration of air, snow, precipitation and sediment measurements with water and wildlife data to help improve understanding of the cumulative impact of contaminants on ecosystems within the AOSR. Models will be used to integrate these measurements along with emissions information.




Dr. Jeff Brook is a senior scientist at Environment Canada (EC) and an assistant professor in the Dalla Lana School of Public Health and Department of Chemical Engineering at the University of Toronto. Dr. Brook leads EC’s mobile lab activities, and projects studying urban and regional air quality, emphasizing fine particulate matter, interactions with meteorology and exposure assessment related to a range of health studies. He co-leads a Canadian Network of Centres of Excellence (AllerGen) program on Genes and Environment and leads the environmental exposure assessment component of a national birth cohort, known as CHILD, examining the influences of environmental factors on children’s health.

Dr. Jane Kirk did her PhD at the University of Alberta, and is now an Environment Canada Research Scientist in the Aquatic Contaminants Research Division and adjunct professor at the University of Toronto Mississauga. Dr. Kirk’s research program aims to understand the impacts of environmental stressors on aquatic ecosystems.