![](http://3.bp.blogspot.com/_xs9T-jlzwhA/THI3UW8VmRI/AAAAAAAAmkw/glxSto2K1I0/s320/0,,2292727_4,00.jpg)
The iconic symbol of the Arctic - the polar bear - is under threat from the twin challenges of climate change and lingering chemical pollutants, such as PCBs (polychlorinated biphenyls), which are not breaking down in the region's cold waters.
A comprehensive review of research on polar wildlife published recently in the journal Science of The Total Environment has concluded that the retreat of sea ice cover in the Arctic as a result of climate change could increase the exposure of species such as polar bears to a range of man-made chemical compounds, including flame retardants and substances used to harden plastics.
Scientists believe that lingering pollutants, locked up in the polar ice for decades, could be released into the ocean as the ice cover retreats.
![](http://3.bp.blogspot.com/_xs9T-jlzwhA/THI5HEKqqdI/AAAAAAAAmk4/sd__OEX6M9M/s280/polar-ice-caps-melting.jpg)
The world's polar bear population is currently estimated to total between 20,000 and 25,000 specimens, despite the Arctic region's vast size.
At great risk
The chemicals don't break down well in the Arctic waters. Polar bears
![](http://3.bp.blogspot.com/_xs9T-jlzwhA/THI6rSwNVZI/AAAAAAAAmlI/i5JSmHzoEpY/s320/coastal-arctic-food-web-drift-ice.png)
"These contaminants are bio-accumulated and bio-magnified up the food chain," said Jenssen. "So the higher you are in the food chain, the higher are the contaminants."
The fact that a polar bear's favorite meal is seal does not help matters in any way.
"These contaminants accumulate in fat,
![](http://3.bp.blogspot.com/_xs9T-jlzwhA/THI65I9O45I/AAAAAAAAmlQ/K_DnlfTXWDc/s280/eat-polar-bear-liver-4.jpg)
Jenssen emphasizes that the contaminants involved are toxic, even in low concentrations. They can affect a polar bear's hormone system and immune system, which is likely to have an influence on the animals' overall reproduction and survival rates.
A contaminated environment
![](http://4.bp.blogspot.com/_xs9T-jlzwhA/THI8kQIq_5I/AAAAAAAAmlo/lhgdycZsND4/s280/global-warming-polar-bear.jpg)
"Climate change will cause a shift in the spreading of the contaminants throughout the world," Jenssen said.
Chemicals "start to condense, and they don't evaporate any more but stay in the Arctic because the temperatures are so low," according to Reinhold Fieler from Akvaplan Niva, a Norwegian environmental consultancy that specializes in the Arctic.
Arctic sea ice is retreating thanks to climate change, "So we have some
![](http://2.bp.blogspot.com/_xs9T-jlzwhA/THI7xXakfyI/AAAAAAAAmlY/N7oLfuGiF8I/s320/sad.bear.jpg)
The good news, according to Bjorn Munro Jenssen, is that as a species, the polar bear has already demonstrated it can adapt to climate change.
![](http://4.bp.blogspot.com/_xs9T-jlzwhA/THI8OB6_-LI/AAAAAAAAmlg/f_QS7KqH_sQ/s320/images.jpg)
However, he says that the complicating factor of chemical contaminants may hinder this natural adaptation.
Source:
DW-World, "Ice-trapped pollutants poison polar bears' diets", accessed August 23, 2010
No comments:
Post a Comment