Toxic pollution in the Arctic

Polar bears in a frozen wilderness. A pure, unpolluted environment. Wrong! Recent scientific research shows that, in some areas, polar bears are exposed to high levels of poisons and pollutants.

Persistent organic pollutants (POPs) include a wide range of poisonous substances such as heat resistant chemicals like PCBs, industrial by-products such as dioxins and furans which come from waste incineration; and pesticides like DDT, dieldrin and lindane. In addition to staying in the environment for a long time, POPs are a special concern because, as one animal eats another, these poisons are concentrated in fat and stored in vital organs in the animal that has eaten poisoned prey. As a top predator, polar bears are exposed to high levels of such pollutants through their food.

Due to the direction of prevailing winds and ocean currents, these substances are concentrated in parts of the Arctic. Most POPs are banned, but they are still used widely in Russia, eastern Europe, and Asia.

Long-range POPs currently represent the most serious pollution-related threat to polar bears.

Bears with high levels of some POPs have low levels of vitamin A, thyroid hormones, and some antibodies. These are important for a wide range of biological functions, such as growth, development, reproduction, behavior, and the ability to fight off diseases.

Newborn cubs are especially vulnerable to these pollutants. In some areas, the mother's milk on which they are totally dependent for growth and development, contains particularly high concentrations of these chemicals. The milk can actually poison the cubs, leading to lower survival rates.

Pseudohermaphroditism, a long word meaning that females have partially-developed male sexual organs, has been observed in 1.5 per cent of the polar bears sampled on Svalbard in recent years. Scientists believe this could be the result of long-range pollutants.

There are also reasons to worry about other pollutants. A wide range of new, man-made persistent substances are making their way to and are being concentrated in the Arctic. The effects of these are still unknown. In addition there are other pollutants that we know about, but that we are not studying due to lack of resources. These include both POPs and other contaminants, such as stain repellents known as PFOS, and brominated flame retardants. These may have similar impacts on polar bears as those already documented.