- OSLO, Norway (AP) -- Polar bears fear nothing they can see in their
icy domain -- but they can't see polychlorinated biphenyls, and scientists
worry the bears are succumbing to the invisible toxins.
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- Last year, researchers in Norway's remote
Svalbard islands reported they found seven female polar bears with vestigial
male organs. Research team leader Andrew Derocher says the anomaly may
be caused by toxic chemicals.
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- Derocher, a Canadian affiliated with
the Norwegian Polar Institute, will lead a team to the Svalbards to try
to determine whether PCBs and other toxins have affected polar bears' immune
systems.
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- "We are going to study the Svalbard
bears, which is the most polluted population in the world, and compare
them with a low-end population in Canada," he said.
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- The Svalbard archipelago, just 600 miles
from the North Pole, might seem to be about as far as possible from man's
pollution.
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- But the islands are at a crossroads of
air and ocean currents bringing pollution from distant industrial sites
in Europe, North America and even Asia.
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- The level of PCBs in the Svalbards is
at least 2.5 times higher than in Canada's polar bear territory, Derocher
said. Other scientists have reported levels of PCBs in Svalbard bears 10
times higher than in Alaska.
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- PCBs, chemical compounds once widely
used in plastics and electrical insulation, were banned in the United States
in the 1970s and are restricted under international agreements. But it
takes years, even decades, for them to break down.
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- PCBs dissolve readily in animal fat,
such as blubber, and stay there. A polar bear's favorite food is seal blubber.
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- Derocher and his team are headed to Svalbard
for an Aug. 8-16 study in which they plan to mark attach radio-tracking
devices to 30 adult bears and up to 20 cubs and give them vaccine designed
to test their immune systems.
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- Then, four to six weeks later, they will
track down the same bears to see how their immune system responded to the
vaccine.
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- "We want to test the ability of
the immune system in these high pollution bears," he said. The results
will be compared with Canadian bears to be tested next year in Wapsuk National
Park.
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- He said the level of PCBs found in Svalbard's
bears are similar to those shown to have caused damage to seals, otters
and mink, ranging from short-term memory loss to sterility and a reduced
ability to withstand disease.
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- Derocher said the Svalbards and the ice-pack
to the north probably sustain a population of 4,000-5,000 bears in a 100,000-square-mile
area, where they have no natural enemies. The population of bears, which
grow to 440- to 880-pounds, has appeared stable since Norway banned hunting
them 25 years ago.
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- But if their immune systems are weakened
or fail, that could quickly change, he said.
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- "If they were hit by a disease,
there could be a great impact in decades, even in years," Derocher
said. "It is certainly something to be concerned about," he said
about the toxins.
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