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CURWOOD: It was 20 years ago on April 26th that Unit 4 at the Chernobyl Nuclear Power Plant in Ukraine erupted like a radioactive volcano. It was, and still is, the worst nuclear accident in history. Chernobyl's nuclear core burned for 10 days, sending tens of tons of radioactive particles into the air. The radiation spread across the entire Northern Hemisphere, including the United States. Studies over the last two decades have been inconclusive about the disaster's human and environmental costs. But two just-released reports predict that the loss of human life could be much higher than many previously thought. Living on Earth's Bruce Gellerman has the details.
GELLERMAN: A decade ago, on the tenth anniversary of the disaster, I traveled to Chernobyl.
[READING OF GEIGER COUNTER]
GELLERMAN: A Geiger counter is standard equipment in the 18-mile exclusion zone around the doomed reactor. One hundred thirty-five thousand people were evacuated from the area. People aren't supposed to live here. The rolling hills and forests are now, and perhaps forever, radioactive.
The hottest place is ground zero. A 300,000-ton concrete and steel sarcophagus entombs the unit 4 reactor. Still it leaks radiation. The Geiger counter jumps.
[RUSSIAN...4. 5 MILLIREMS....RUSSIAN]
GELLERMAN: After just a minute my guide Sasha wanted to leave.
SASHA: Machina. Better to the car.
GELLERMAN: Why is that?
SASHA: Because it's rather high. The regulation is like this 5 rem is the limit. 5 rem is the limit and you're out.
GELLERMAN: You've been working here how many years?
GELLERMAN: How many rem do you have?
SASHA: I don't know. And I'm not interested in it.
GELLERMAN: Why aren't you interested in learning how much?
SASHA: Because it is easier to live.
GELLERMAN: Scientists generally agree that 31 workers and firemen died immediately after the reactor exploded, and nine children have since died from thyroid cancer. But that's basically where the agreement ends. Measuring the effects of Chernobyl is an intense scientific and political controversy.
The largest study was conducted by eight UN agencies, including the IAEA, the International Atomic Energy Agency, and World Health Organization. The results were released last year.
Dr. Michael Repacholi, manager of the WHO's radiation program, says the study sends a reassuring message:
REPACHOLI: Well, I think that it tells people what the numbers really are. That there's no speculation in that. There's some uncertainty in the values, but it's very close around the 4,000 mark for cancer deaths, and the other speculations are just not valid.
GELLERMAN: But now another just-released study by UN scientists in France, says the number of Chernobyl cancer deaths could be nine times that many. Some nuclear power critics charge, this is what they've been saying all along.
HARMS: This is really a scandal.
GELLERMAN: Rebecca Harms is the Green Party's representative to the European parliament. She cites another study, called The Other Chernobyl Report, it predicts 30 to 60 thousand people will die from Chernobyl cancers, not 4,000, as the UN estimates. The difference is that the IAEA only looked at the 600,000 so-called liquidators; those who cleaned up the disaster and had the highest radiation exposures. Rebecca Harm says the green study included all of Europe.
HARMS: For health and environment, we can show that all figures which have been published by the IAEA are wrong and misguiding.
GELLERMAN: So you're suggesting ? more than suggesting ? you're saying that the IAEA has deliberately downplayed the health effects of Chernobyl?
HARMS: Yes, yes, yes.
GELLERMAN: Researchers acknowledge predicting Chernobyl cancer deaths is an uncertain science. Dr. Fred Mettler was chairman of the science panel that prepared the UN report on Chernobyl's health effects.
METTLER: What we said in the report, on that particular section on mortality, was the exact number of deaths due to this accident will probably never be known.
On average a quarter of the population dies from cancer . So, a few thousand, even a few tens of thousand, extra deaths is difficult to measure. Especially when exposure levels are low:
METTLER: What effect would smoking, you know, in Boston have on killing people in Europe? I mean, if one wants to make those calculations, nobody can stop you from making them, but the dose levels are certainly well below anything anybody has seen cancer increases at.
GELLERMAN: Scientists aren't only looking at cancer. New studies indicate a rise in cataracts and perhaps heart disease among people exposed at levels previously considered too low to have an effect. To understand the long-term impact of radiation Chernobyl researchers have had to turn to Japan.
Chernobyl produced 250 times as much radiation as was created by the atomic bombs dropped on Hiroshima and Nagasaki combined. Dr. Fred Mettler:
METTLER: All I can say is, two to three generations out after dropping atomic bombs on a pretty large population, there is no evidence there of increased genetic damage.
GELLERMAN: Likewise, the UN study found no evidence of genetic damage due to Chernobyl, but the intense burst of radiation from a bomb isn't the same as long term, low level exposure. A lot less is known about that. And according to Dr. Tim Mousseau, a biologist from the University of South Carolina, there is evidence of genetic effects from Chernobyl, at least in some birds. Mousseau has studied barn swallows around Chernobyl for six years ? 18 generations.
MOUSSEAU: We found mutations at the level of sperm morphology, sperm swimming behavior, as well as visible mutations on the bodies of these birds, including what we call partial albinos, where parts of the birds' bodies are completely white. And this is linked to mutations in the populations of barn swallows that live in the most contaminated areas.
GELLERMAN: And Mousseau says genetic damage from Chernobyl dramatically decreased the barn swallows reproduction rate. But birds aren't people, and susceptibility to radiation varies from species to species, even from individual to individual.
Yet, despite competing studies there are lessons to be drawn from Chernobyl, says Dr. Fred Mettler, who chaired the UN report. For all intents and purposes, Chernobyl was a dirty bomb, and is therefore useful in preparing for a nuclear terrorist attack:
METTLER: There's a lot of data about cesium in the environment, and of course cesium is one of the things people think about in dirty bombs. So there's a lot of data in this report about how cesium acts in urban environments and how it sticks to buildings and how people get it into them and how fast it comes out of them. And all that is incredible data for planning from Homeland Security purposes.
GELLERMAN: So the legacy of Chernobyl is that, what we learn from it, may one day save us...from ourselves. For Living on Earth, I'm Bruce Gellerman.
International site for information on Chernobyl The International Atomic Energy Agency on Chernobyl Critical analysis of a recent report by the IAEA and WHO on Chernobyl