When University of Georgia researchers hold a Geiger counter over rodents living near the Chernobyl Nuclear Power Plant in the Ukraine, the clicks grow quickly into a continuous roar.
"You wouldn't want to handle an animal like that, and yet they are surviving," said Cham E. Dallas, a UGA associate professor of pharmacology and toxicology, who - with fellow researchers - has made eight expeditions to Chernobyl since 1991.
The wildlife near Chernobyl, the site of the world's worst nuclear disaster, not only survives, it abounds in the area, now largely abandoned by humans. Species of fish and rodents do exhibit genetic change, but no apparent defects, according to Dallas.
The surprising data suggest that the environmental damage caused by Chernobyl was less severe than many experts had feared. Nevertheless, Dallas cautioned, it is too early to tell what the long-term effects of the disaster will be.
Dallas is presenting a paper summarizing his Chernobyl research during the American Chemical Society's 1997 annual meeting in Las Vegas, which runs through Friday, Sept. 12.
He and his colleagues also have published their findings in Nature and journals devoted to ecotoxicology and similar areas of study. The research is funded by the U.S. Department of Energy.
A 1986 explosionand fire in Chernobyl's Reactor 4 released 100 times more radioactivity than was released by the combined atom-bomb explosions at Hiroshima and Nagaski in 1945. UGA researchers have documented unprecedented levels of radiation in fish and rodents living in the area.
UGA researchers have considerable experience in radioecology, the study of bioeffects in the environment, through their work at the Savannah River Ecology Laboratory. Since 1951, SREL scientists have conducted ecological research at the Savannah River Site, a nuclear weapons materials processing complex on the Georgia-South Carolina border near Aiken, S.C.
Experience at the SREL has shown that, "a great deal of contamination over time ended up in aquatic species," Dallas said. Catfish, carp and other species of fish that Dallas has examined near Chernobyl show levels of radioactive contamination three to five times higher than anything found in the United States.
Rodents such as voles show even higher levels of contamination, as much as 10 times the levels found in U.S. rodents. "No one has ever seen levels like that before," Dallas said. UGA researchers also have found genetic changes in these animals.
"I use the word change and not damage," Dallas said, because the implications of the changes remain unclear. "We found no deformed animals. None at all."
Dallas and his colleagues recently expanded their Chernobyl studies to include humans. The government of the former Soviet Union allowed the reactor to burn for three days before informing the 50,000 residents of nearby Pripyat of the accident. Pripyat residents, meanwhile, went about their regular business. Some even watched the reactor burn from their balconies.
The UGA researchers are focusing their human studies on the "liquidators," the thousands of people who cleaned up the contamination around the reactor accident site with "bucket and shovel technology."
Many cleanup personnel have developed thyroid cancers from radioactive iodine, which the reactor accident released in large quantities. "Their health is really hurting," Dallas said.
Most of the human contamination is clustered along transportation arteries, especially train routes. People in the area buy their food on train platforms, much as they did in the United States 50 and 100 years ago. Many of these trains passed through the contaminated area.
The human health problems could worsen as the years pass. "In human populations, we're still waiting for the big effects," Dallas said.
Dallas initiated his Chernobyl studies because the site offered an unmatched opportunity to study the impact of a large release of radioactivity into the environment. The project led to the first application of clinical analysis techniques, such as superoxide dismutase (SOD), to field studies.
Nutritionists use SOD to measure levels of oxygen scavengers, which gobble up harmful, chromosome-damaging oxygen radicals in the body. Radioactivity produces oxygen radicals, so Dallas's team can use SOD as an indirect measure of its presence.
The UGA researchers conduct their month-long field trips to Chernobyl under logistically trying conditions. They must take their own food into contaminated areas guarded by machine-gun-toting soldiers. Gas for their vans is hard to come by. And they must often work wearing protective suits, respirators and radiation monitors.
Still, the effort is worth the trouble, according to Dallas. "We're getting a picture no one else has been able to get," Dallas said.
Although the Chernobyl accident happened 11 years ago, there could be more catastrophic releases of radiation into the environment in the future. Another nuclear-reactor accident is a possibility, but so is a nuclear-bomb attack by terrorists. "We're going toneed to know how to guage that sort of impact," Dallas said.
The above story is based on materials provided by University Of Georgia. Note: Materials may be edited for content and length.
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