WASHINGTON - September 24 - Three new scientific studies provide strong indications that toxic contamination of polar bears is correlated to negative health impacts. This research contributes to the ever-growing evidence of the dangers toxic chemicals pose to wildlife and people, according to World Wildlife Fund.
The new research demonstrates that biological changes in the hormone and immune systems of polar bears are linked to the levels of toxic contaminants in their bodies. For example, 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. Altered hormone levels could result in a wide range of negative health impacts, such as development, behavior, and reproductive problems.
"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 has contributed to all of the recent studies on Arctic polar bear contamination. "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."
WWF stresses that although the toxic contaminants that were analyzed in these studies are no longer widely used in manufacturing processes or in farming, these chemicals are slow to break down in the environment and can remain in water, ice, and soil for many years.
"Other contaminants, with similar properties, continue to be used on a day-to-day basis in manufacturing processes and products throughout the world," said Clifton Curtis, director of WWF's Toxics Program. "It is crucial to prevent these newer- generation chemicals from accumulating in, and polluting, our environment."
Most chemicals on the market today have not been adequately tested to determine their impacts on human and wildlife health. According to WWF, there is an urgent need for safer chemical regulation, including a strong version of the European Union's proposed chemical reform legislation known as REACH, 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.