Toxic Waste Creates Hermaphrodite Arctic Polar Bears
/January 10, 2006 by the Independent <http://www.independent.co.uk> / UK /
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Toxic Waste Creates Hermaphrodite Arctic Polar Bears *
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by David Usborne*
http://www.commondreams.org/headlines06/0110-01.htm
Wildlife researchers have found new evidence that Arctic polar bears,
already gravely threatened by the melting of their habitat because of
global warming, are being poisoned by chemical compounds commonly used
in Europe and North America to reduce the flammability of household
furnishings like sofas, clothing and carpets.
Polar bears - the world's largest bears - are facing a bleak future
because of global warming and experts want them declared a vulnerable
species. (Photo: The Age)
A team of scientists from Canada, Alaska, Denmark and Norway is sounding
the alarm about the flame retardants, known as polybrominated diphenyls,
or PBDEs, saying that significant deposits have recently been found in
the fatty tissues of polar bears, especially in eastern Greenland and
Norway's Svalbard islands.
Studies are still being carried out on what impact the chemicals might
be having on the bears, but tests on laboratory animals such as mice
indicate that their effects can be considerable, attacking the sex and
thyroid glands, motor skills and brain function.
There is also evidence that compounds similar to the PBDEs have
contributed to a surprisingly high rate of hermaphroditism in polar
bears. About one in 50 female bears on Svalbard has both male and female
sex organs, a phenomenon scientists link directly to the effects of
pollution.
"The Arctic is now a chemical sink," declared Colin Butfield, a campaign
leader for the Worldwide Fund for Nature, which last month indicated
that killer whales in the Arctic were also suffering from elevated
levels of contamination with fire retardants as well as other man-made
compounds. "Chemicals from products that we use in our homes every day
are contaminating Arctic wildlife."
The pollutants are carried northwards from industrialised regions of the
US and western Europe on currents and particularly on northbound winds.
Contaminated moisture often condenses on arriving in the cold Arctic
climes and is then deposited, ready to enter the food chain.
For several years, scientists have observed how the concentrations of
the pollutants are magnified as they ascend the food chain, from
plankton to fish and then to marine mammals such as seals, whales and
polar bears. The new study, first published last month in the journal
Environmental Science and Technology, shows, for instance, that one
compound was 71 times more concentrated in polar bears than in the seals
they normally feed upon.
Conservationists are especially alarmed by these new findings because of
the already fragile condition of the Arctic polar bear populations, some
of which could be devastated before the end of the century. As warming
temperatures erode their hunting grounds, polar bears in Canada's
western Hudson Bay region, for instance, saw their numbers slide from
1,100 in 1995 to only 950 in 2004.
The dangers now posed by the PBDEs are reminiscent of the crisis 30
years ago over PCBs - polychlorinated biphenyls - a highly toxic
by-product of many industries that was also found to be migrating to the
Arctic. The dumping of PCBs was swiftly banned. Since 2004,
manufacturing has stopped in the US of two of the most toxic retardants,
called penta and octa. Stockpiles of both still exist, however.
According to Derek Muir, of Canada's Environmental Department and a
leader of the new research, there are signs of a slightly different
retardant, typically used in construction materials and furnishings,
also showing up in the Arctic and in the bears, called HBCD. "It's a
chemical that needs to be watched, because it does biomagnify in the
aquatic food webs and appears to be a widespread pollutant."
The research team tested 139 bears captured in 10 different locations
across the Arctic region. They found that the bears in Norway's
Svalbard, a wildlife refuge where all hunting is banned, had 10 times
the levels of the chemicals than bears in Alaska and four times those in
Canada. |