WWF-UK: Toxics put 22,000 polar bears at risk from infection
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Toxics put 22,000 polar bears at risk from infection
Monday 13 September 2004
New scientific research provides evidence that 22,000 polar bears are exposed to the risk of infection due to toxic contamination affecting their immune systems.
The three new scientific studies show that biological changes in the hormone and immune systems of polar bears are linked to the levels of toxic contaminants in their bodies. The higher the level of PCBs (polychlorinated biphenyls) and several pesticides in polar bears in Canada and on the Norwegian island of Svalbard, the lower the level of antibodies in their blood.
Toxic chemicals were also correlated with steroid hormone cortisol and thyroid hormone levels in Svalbard polar bears. Reduced levels of antibodies leave bears more susceptible to infection. These altered hormone levels could result in a wide range of negative health impacts, such as development, behaviour, and reproductive problems in the future.
"The studies conducted on polar bears over the last few years all conclude that these animals are negatively affected by chemical pollution," said Dr Andrew Derocher, who contributed to all of the recent studies on polar bear contamination in the Arctic.
"Most polar bears probably have several hundred man-made chemicals in their bodies and they have never evolved mechanisms to deal with them. The unintentional tinkering with the hormone and immune system of a polar bear is unlikely to be good for them."
"Other contaminants, with similar properties, continue to be used on a day-to-day basis in manufacturing processes and products throughout the world," said Brettania Walker, Toxics Officer in WWF's Arctic Programme.
"It is crucial to prevent these newer-generation chemicals from accumulating in, and polluting, the environment."
Most chemicals on the market today have not been adequately tested to determine their impacts on human and wildlife health. WWF believes there is therefore an urgent need for safer chemical legislation, including a strong and protective version of the currently debated EU's REACH legislation, which would help protect humans and animals such as the polar bear from potentially harmful chemicals.
The estimated 22,000 polar bears living in the Arctic are not only under threat from toxic chemicals, but also from the combined effects of climate change, and habitat loss, creating more stress amoung the animals and increasing the chance of infection. WWF is calling for the immediate phase out of the most hazardous chemicals.
Toxic chemicals were also correlated with steroid hormone cortisol and thyroid hormone levels in Svalbard polar bears. Reduced levels of antibodies leave bears more susceptible to infection. These altered hormone levels could result in a wide range of negative health impacts, such as development, behaviour, and reproductive problems in the future.
"The studies conducted on polar bears over the last few years all conclude that these animals are negatively affected by chemical pollution," said Dr Andrew Derocher, who contributed to all of the recent studies on polar bear contamination in the Arctic.
"Most polar bears probably have several hundred man-made chemicals in their bodies and they have never evolved mechanisms to deal with them. The unintentional tinkering with the hormone and immune system of a polar bear is unlikely to be good for them."
"Other contaminants, with similar properties, continue to be used on a day-to-day basis in manufacturing processes and products throughout the world," said Brettania Walker, Toxics Officer in WWF's Arctic Programme.
"It is crucial to prevent these newer-generation chemicals from accumulating in, and polluting, the environment."
Most chemicals on the market today have not been adequately tested to determine their impacts on human and wildlife health. WWF believes there is therefore an urgent need for safer chemical legislation, including a strong and protective version of the currently debated EU's REACH legislation, which would help protect humans and animals such as the polar bear from potentially harmful chemicals.
The estimated 22,000 polar bears living in the Arctic are not only under threat from toxic chemicals, but also from the combined effects of climate change, and habitat loss, creating more stress amoung the animals and increasing the chance of infection. WWF is calling for the immediate phase out of the most hazardous chemicals.
Further information
To find out more about our work on hazardous chemicals and to see how you can make a difference visit our Chemicals and Health website.
The three new studies published in 2004:
1. Lie E, Larsen HJ, Larsen S, Johansen GM, Derocher AE, Lunn NJ, Norstrom RJ, Wiig O, Skaare JU. Does high organochlorine (OC) exposure impair the resistance to infection in polar bears (Ursus maritimus)? Part I: Effect of OCs on the humoral immunity. J Toxicol Environ Health A. 2004 Apr 9; 67(7):555-82.
2. Oskam I, Ropstad E, Lie E, Derocher A, Wiig O, Dahl E, Larsen S, Skaare JU. Organochlorines affect the steroid hormone cortisol in free-ranging polar bears (Ursus maritimus) at Svalbard, Norway. J Toxicol Environ Health A. 2004 Jun 25;67(12):959-77.
3. Braathen M, Derocher AE, Wiig O, Sormo EG, Lie E, Skaare JU, Jenssen BM. Relationships between PCBs and thyroid hormones and retinol in female and male polar bears. Environ Health Perspect. 2004 Jun;112(8):826-33.
WWF stresses that although the toxic contaminants that showed up in these studies are no longer widely used in manufacturing processes or in farming, they are slow to break down in the environment and can remain in water, ice, and soil for many years.
These studies relied on blood and tissue samples taken between the years 1995-1999.