One might think that a remote location, such as the Arctic, would be clean and free of pollution. Toxic contaminants would be the last thing you'd expect to find there. But this is not the case.
Even the Arctic is susceptible to pollution. Chemicals from faraway industrial and agricultural sources affect the northern environment.
Scientists with Parks Canada have been monitoring water quality in the Thomsen River in Aulavik National Park since 1999. Results show that the river's water quality is excellent. However, they have detected traces of the pesticide lindane. The pesticide likely came from as far away as Asia.
Contaminants reach the Arctic by long-range transport: for the most part, they travel on air currents. Once airborne pollutants arrive in Canada's North, cold temperatures cause the air, and the chemicals in it, to fall lower in the atmosphere. The pollutants reach the ground and the water.
Scientists who study Arctic ecosystems have found a number of contaminants from distant sources. Three types are particularly worrisome: POPs (persistent organic pollutants), heavy metals (such as mercury, cadmium and lead) and radionuclides (radioactive atoms).
Contaminants accumulate along the food chain and can eventually threaten human health. (Learn more about bioaccumulation). In fact, the potential for human exposure to contamination is greater in the Arctic than in many other regions.
By themselves, Canada and other northern countries cannot prevent contaminants from reaching Arctic environments. It will take cooperative global action to end the problem.
POPs (persistent organic pollutants) and heavy metals show up in seals, whales and walruses in Canada's Arctic.
The chemicals drift long distances in the air and return to the ocean in rain or snow. There, they enter the food web. They have been found in people who live in the North.
In 2001, Canada signed an international treaty to ban 12 especially nasty toxics. These "dirty dozen" include PCBs, dioxins and benzene.