Accumulation of PCBs and
other POPs in Canada's Arctic

By Nafysa Lalani, B.Sc., Bennett Environmenal Inc.

The excessively high level of POPs in Arctic environments has led to research into the pathways by which the POPs reach the area.

The long-distance transport of Persistent Organic Pollutants (POPs) such as PCBs into Canada's Arctic has caused health and environmental risks to the indigenous people of that area. A study of sea-food traditionally eaten by First Nations' people of the Arctic has shown that they have markedly high levels of PCBs in their diet. As PCBs have never been manufactured in the region, these high concentrations cannot be attributed to local sources. Rather, they have been transported from other regions.

The excessively high level of POPs in Arctic environments has led to research into the pathways by which the POPs reach the area. Due to the Arctic's cold climate and geographic characteristics, it is a sink for contaminants such as PCBs, originating from around the world.

The Arctic air mass efficiently transports particle-size contaminants across the Pole, from industrialized regions of Eurasia. Semi-volatile compounds are carried to the Arctic by cycles of evaporation, transport, and condensation. Rain, snow, ice and dry deposition capture the airborne contaminants and pollute the surfaces on which they settle. Rivers process contaminants by sedimentation and resuspension of particles. Lakes, estuaries, and deltas act as sediment traps and sinks for contaminants.

Melting ice releases its contaminants into the biologically dynamic shelf seas and in the North Atlantic. It is from here that contaminants are passed into the food chain. Ocean currents serve as an important PCB contaminant pathway as well, capturing water with particle-adsorbed and water-soluble contaminants from remote industrialized coasts into the Arctic within a few years.

Although the use of PCBs was prohibited over 20 years ago in most industrialized countries, they continue to accumulate in the Arctic today. Dr. Frank Wania of the Norwegian Institute of Air Research states that chemicals can take between a few weeks and decades to reach the north. Contaminants are trapped most efficiently in the cold climate of the Arctic than in any other region of the world.

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