KIEV, Ukraine—In 1986 the worst nuclear accident in history took place when reactor No. 4 in the power plant at nearby Chernobyl exploded, spewing large amounts of radiation into the atmosphere. Now, almost 25 years later, the lesson that scientists are learning is that radiation might not be the only cause of this disaster's long-term medical effects, and perhaps not even the main one.

The explosion immediately killed two workers, and 28 firemen and nuclear power plant staff died from acute radiation syndrome in the three months afterward. The disaster also released a plume of radioactive fallout that contaminated more than 200,000 square kilometers of Europe, roughly three quarters of which lies in the former Soviet republics of Belarus, Russia and Ukraine. Hints of fallout were also detected elsewhere in the Northern Hemisphere, reaching Japan in six days and the U.S. in 10, but in most cases only negligible amounts were found.

Investigators of the medical consequences of the disaster must contend with both the very real effects of the tragedy and the desire to blame every bad medical outcome on Chernobyl. A major challenge lies in figuring out how much fallout was released during the event. Estimates range from roughly 5 percent of the radioactive material in the reactor, which is what is usually cited, to 95 percent, says civil and environmental engineer Eric Schmieman of Battelle Memorial Institute. It is difficult to make a firmer assessment because the contemporary hazards at the Chernobyl site prevent safe surveys.

Therefore, it remains difficult to know who was exposed to radiation from the event and how large a dose they received, and then to figure out the fallout's real effects. A 2005 report from the Chernobyl Forum, which is made up of the International Atomic Energy Agency (IAEA) and seven United Nations agencies, along with Belarus, Russia and Ukraine, estimated that five million people currently live in contaminated areas of those three countries. In addition, 350,000 workers helped contain and clean the accident, and roughly 240,000 of these "liquidators" worked in key activities at the reactor and in the 30-kilometer "exclusion zone" surrounding the accident. (Later, the number of registered liquidators rose to 600,000, although only a small fraction of these were exposed to high levels of radiation, the report noted.)

There is heated debate about how many deaths should be linked to the tragedy and its fallout. The IAEA's 2005 Chernobyl Forum report estimated that 4,000 such casualties might occur among the 600,000  people they considered . In response, the European Green Party commissioned an alternative study released in 2006, "The Other Report on Chernobyl," or the TORCH report, which estimated 30,000 to 60,000 extra cancer deaths.

"Radiation is the obvious and even exaggerated culprit with Chernobyl," says health physicist Vadim Chumak at the Academy of Medical Sciences of Ukraine's Research Center for Radiation Medicine in Kiev. It's not that simple, he says, adding: "One must consider a whole variety of factors when it comes to Chernobyl."

The problem with studying the effects of this fallout is that the world is bathed with naturally occurring low-level radiation, with sources ranging from long-distance air travel to plasma televisions. There are other confounding factors researchers must cope with as well, such as industrial pollution and differences in lifestyle and health care. In addition, they have to deal with the fact that looking for Chernobyl-linked problems might turn up ones that might have escaped medical attention otherwise but had nothing to do with the disaster. For instance, when it comes to victims of the atomic bombs dropped on Hiroshima and Nagasaki, those who did not die of acute radiation syndrome or the widespread lack of medical care after the attacks lived longer than other members of their generation because they received government-sponsored medical attention for the rest of their lives, Chumak says.

5 Comments

1. 1. JamesDavis in reply to ConcernedCitizen 07:50 AM 3/17/11

   What makes you think your made up figures are more accurate than the other made up figures? You call yourself 'ConcernedCitizen' when you do not seem all that concerned about human life or any other life. Why would we want to build a source of energy that is as deadly and destructive as radioactive power plants have proven themselves to be when there are cleaner, safer and cheaper to build and maintain energy sources like the first commenter said? We are trying to get away from killer sources of fossil fuel and nuclear is a very dangerous and destructive form of fossil fuel. We no longer have to use fossil fuel for anything, so why are people trying to turn this deadly and destructive form of fossil fuel into a never ending debate like they did with abortion? Are you so eager to destroy human life that you would go to any means to do so?

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2. 2. ConcernedCitizen 01:38 PM 3/17/11

   I know of no sources of energy that are "cleaner, safer AND cheaper to build and maintain." Comparing the costs of solar and wind to coal and nuclear will show that they cost around 3-4 as much to build, based on the most currently constructed power plants. Switching to solar/wind would mean everything in our country would cost 3-4x as much, which would make us unable to compete in this world economy and cause massive economic hardships with increased deaths and suicide rates as this nation becomes overwhelmed with poverty. Environmentalists like to think that we can just flip on a switch and convert everything to solar/wind, but they fail to look at the consequences of this action.
   
   Nuclear is an imperfect technology, but a necessary evil until we either perfect fusion or solar/wind/geothermal/tidal increase to an efficiency level that is sustainable.

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3. 3. Bett in reply to ConcernedCitizen 04:09 PM 3/17/11

   Cleaner, safer or cheaper? Pick any two. Except for clean and cheap, or safe and cheap. Oh - sorry, well I guess you can't have either clean OR safe along with cheap.
   
   I think that the people who are effected by this terrible disaster and who didn't find suicide attractive might wish that they had paid higher fuel bills for a less lethal form of power generation.
   
   Many of us already live frugally, energy-wise. Many of us already eschew products that are made, raised or grown by energy and resource intensive methods. You'll excuse us for thinking that we should not suffer for the profligate lifestyles of others.
   
   NO NUKES!

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4. 4. KaiGeologist 03:24 AM 3/18/11

   
   2-10 000 times our background level radiation is not so bad at all, it can even make you healthier?
   See:
   
   Dose Response. 2010; 8(2): 148–171. PMCID: PMC2889503
   2010 University of Massachusetts
   Observations on the Chernobyl Disaster and LNT
   Zbigniew Jaworowski
   www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC2889503/#b56-drp-08-148
   
   …. The most nonsensical, expensive and harmful action, however, was the evacuation of 336,000 people from contaminated regions of the former Soviet Union, where the radiation dose from Chernobyl fallout was about twice the natural dose. Later this limit was decreased to even below the natural level and was some five times lower than a radiation dose rate of 5.25 mSv/year at Grand Central Station in New York City (Benenson et al 2006).
   
   The evacuation caused great harm to the populations of Belarus, Russia and the Ukraine. It led to mass psychosomatic disturbances, great economic loss and traumatic social consequences. According to Academician Leonid A. Ilyin, the leading Russian authority on radiation protection, the mass relocation was implemented by the Soviet government under the pressure of populists, ecologists and self-appointed “specialists”, and it was done against the advice of the best Soviet scientists (Ilyin 1995; Ilyin 1996). The really dangerous air radiation dose rate of 1 Gy/h on 26 April 1986 (0.01 Gy/h 2 days later) covered an uninhabited area of only about 0.5 km2 in two patches reaching up to a distance of 1.8 km southwest of the Chernobyl reactor (UNSCEAR 2000b)...

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5. 5. piyknoa in reply to JamesDavis 06:41 PM 9/26/11

   Uranium is NOT a fossil fuel.
   
   "Different alternative sources of energy [than fossil fuels] include *nuclear*, hydroelectric, solar, wind, and geothermal." "The main use of uranium in the civilian sector is to fuel nuclear power plants. One kilogram of uranium-235 can theoretically produce about 80 terajoules of energy (8×1013 joules), assuming complete fission; as much energy as 3000 tonnes of coal."
   
   "Uranium is a naturally occurring element that can be found in low levels within all rock, soil, and water. Uranium is also the highest-numbered element to be found naturally in significant quantities on earth and is always found combined with other elements.[7] Along with all elements having atomic weights higher than that of iron, it is only naturally formed in supernovae."
   
   http://en.wikipedia.org/wiki/Uranium#Occurrence
   http://en.wikipedia.org/wiki/Fossil_fuel#Limits_and_alternatives

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