Toxic Waste Creates Hermaphrodite Arctic Polar Bears
Roald B. Larsen
http://www.independent.co.uk/
Toxic Waste Creates Hermaphrodite Arctic Polar Bears
by David Usborne
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.
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.
© 2006 Independent News and Media Limited
www.commondreams.org/headlines06/0110-01.htm
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