The Arctic: Clean or Contaminated

White snow as far as the eye can see, clean cold water, an uncontaminated haven in a polluted world—this is how people like to picture Canada's North. But these images have been challenged by an increasing body of research showing the presence of contaminants throughout Arctic ecosystems, some arial at surprisingly high levels.

Researchers from Environment Canada's National Water Research Institute (NWRI) are working with other experts in Canada and around the world under the Arctic Monitoring and Assessment Programme (AMAP) to learn more about the extent of these contaminants and their biological effects. NWRI's research has focused on the scientific assessment of persistent organic pollutants (POPs) in the circumpolar Arctic. These chemicals from agricultural and industrial activities in the south are transported north mainly by atmospheric processes, and enter aquatic ecosystems when snow and ice melt in spring.

POPs enter the food chain when they are consumed by aquatic species, and because they are slow to degrade, they bio-accumulate in their tissue. When these species are, in turn, eaten by others further up the food chain, concentrations magnify dramatically. The process is a cause for concern not only because of potential effects on Arctic wildlife, but because of possible impacts on northern peoples, who may be exposed through consumption of traditional foods like fish, marine mammals, birds and caribou.

In 1997, AMAP released a report presenting all available data on organic pollutants in Arctic air, seawater, sediments, and terrestrial, freshwater and marine biota, and gave governments of the eight Arctic countries a clearer picture of the state of the Arctic environment. It also identified gaps in knowledge and recommended further actions to identify sources of pollutants and determine biological effects. Work to address these gaps through further collaborative research has been ongoing ever since.

In Canada, for example, NWRI researchers have begun studying POPs in landlocked char fish in Resolute and Char lakes in the central Canadian archipelago, and are planning to collect annual samples to follow changes over time. In another study, lake sediment cores are being collected along a north-south transect in the Canadian Arctic to learn more about the sources, long-range transport and impacts of new and old organic pollutants and of mercury, a toxic metal increasing in concentration in the Arctic.

Other work focuses on achieving a better understanding of the behaviour of contaminants in high Arctic lakes. Researchers developed a model that took the unique characteristics of these lakes into account and applied it to Amituk and Char lakes. Their results suggest that Arctic lakes act as conduits, not sinks, for chemicals. Most contaminant loading comes from snowmelt and most is exported from the lake, leaving minimal amounts in the sediment. This finding provides important insights into the potential exposure of aquatic biota to contaminants in lake ecosystems.

Researchers involved in northern contaminant research not only publish their work in scientific journals and reports, but also bring this information back to the North to share it with those who are directly affected by contaminants in their environment. Recently, NWRI scientists participated in a tour of hamlets in the Eastern Arctic to make presentations on POPs and metals in marine mammals and birds collected near each community.

These and other studies contribute to Canada's efforts to reduce contaminants in traditionally harvested foods, and help provide the scientific foundation for international agreements to control environmental contamination. Environment Canada experts were in Germany this March for the fourth of five negotiating sessions to develop a global convention on POPs. Canada is one of more than 100 countries involved in the effort, which is aimed at eliminating or reducing emissions of 12 toxic substances linked to health issues in the North.

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