[ RadSafe ] " Chernobyl wildlife baffles biologists "

[Franta, Jaroslav]

Chernobyl wildlife baffles biologists; 
Animals are returning to area near meltdown, but scientists are split on
their long-term fates
Toronto Star, 8 June 2007
Douglas Birch, Associated Press

PARISHEV, Ukraine -- Two decades after an explosion and fire at the
Chernobyl nuclear power plant sent clouds of radioactive particles drifting
over the fields near her home, Maria Urupa says the wilderness is
encroaching. 

Packs of wolves have eaten two of her dogs, the 73-year-old says, and wild
boar trample through her cornfield. And she says fox, rabbits and snakes
infest the meadows near her tumbledown cottage. 

The return of wildlife to the region near the world's worst nuclear power
accident is an apparent paradox that biologists are trying to measure and
understand. 

Many assumed the 1986 meltdown of one reactor, and the release of hundreds
of tonnes of radioactive material, would turn much of the 2,850
square-kilometre evacuated area around Chernobyl into a nuclear dead zone. 

It certainly doesn't look like one today. 

Wildlife has returned despite radiation levels in much of the evacuated zone
that remain 10 to 100 times higher than background levels, according to a
2005 UN report - though they have fallen significantly since the accident. 

Some researchers insist that by halting the destruction of habitat, the
Chernobyl disaster helped wildlife flourish. Others say animals may be
filtering into the zone, but they appear to suffer malformations and other
ills. 

Biologist Robert Baker of Texas Tech University was one of the first Western
scientists to report that Chernobyl had become a wildlife haven. He says the
mice and other rodents he has studied at Chernobyl since the early 1990s
have shown remarkable tolerance for elevated radiation levels. 

But Timothy Mousseau of the University of South Carolina, a biologist who
studies barn swallows at Chernobyl, says a high proportion of the birds he
and his colleagues have examined suffer from radiation-induced sickness and
genetic damage. Survival rates are dramatically lower for those living in
the most contaminated areas. 

Their disagreement reflects a deeper split among biologists who study
exposure to radiation. 

Some, including Baker, think organisms can cope with the destructive effects
of radiation up to a point - beyond which they begin to suffer irreparable
damage. Others believe that even low doses of radiation can trigger cancers
and other illnesses. 

In the Journal of Mammology in 1996, Baker and his colleagues reported that
the disaster had not reduced either the diversity or abundance of a dozen
species of rodents near the Chernobyl plant. 
Genetic tests showed Chernobyl's animals suffered some damage to their DNA,
Baker and his colleagues reported. But they said overall it didn't seem to
hurt wildlife populations. 

Mousseau and others paint a far more pessimistic picture. 
In the March issue of the journal Biology Letters, a group led by Anders
Moller, from Pierre and Marie Curie University in Paris, said that in a
study of 7,700 birds examined since 1991, they found 11 rare or unknown
abnormalities in a population of Chernobyl's barn swallows. 
Roughly one-third of 248 Chernobyl nestlings studied were found to have
ill-formed beaks, albino feathers, bent tail feathers and other
malformations. Mousseau was a co-author of the report. 
In other studies, Mousseau and his colleagues have found increased genetic
damage, reduced reproductive rates and what he calls "dramatically" higher
mortality rates for birds living near Chernobyl. 
The work suggests, he said, that Chernobyl is a "sink" where animals migrate
but rapidly die off. 
Mousseau suspects that relatively low-level radiation reduces the level of
antioxidants in the blood, which can lead to cell damage.
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Can anyone pls. comment on the Mousseau reports ? (Thnx)





















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