The exact number of radiation-related cancers due to Chernobyl will never be known. Radiation-induced cancers do not have a specific signature which would allow them to be differentiated from cancer due to other causes. The potential number of cancers can only be estimated by multiplying risk factors (from the Japanese atomic bomb survivor studies), the Chernobyl population size and the radiation dose.
A reasonable central estimate is about 4,000 fatal radiation induced cancers during the lifetime of the 600,000 most highly exposed individuals and perhaps another 5,000 in more peripheral populations. The number is small (representing a few percent) relative to the normal spontaneous risk of cancer, but the numbers are large in absolute terms. While any such estimates have some “uncertainty”, the current findings are compatible with the risk estimates derived from Japan and clearly rule out the claims of “hundreds of thousands deaths” made by some anti-nuclear groups.
Congenital malformations have been a topic of great media and public interest. The data reviewed by the Chernobyl Forum shows that while congenital malformations are being more commonly reported over time, there is actually a higher rate in the areas with lower contamination and there is no clear relation to radiation exposure.
Has the Chernobyl story ended after 20 years? The answer is ‘no’. The legacy will likely continue for several more decades.
The governments have spent huge amounts of money on social welfare programs that have done little to foster independence and change. The population remains largely unsure of what the effects of radiation actually are and retain a sense of foreboding. A number of adolescents and young adults who have been exposed to modest or small amounts of radiation feel that they are somehow fatally flawed and there is no downside to using illicit drugs or having unprotected sex. To reverse such attitudes and behaviors will likely take years although some youth groups have begun programs that have promise.
Discussion of Chernobyl’s effects almost always concentrates on the adverse outcomes. We should take time to realize that many of the actions of the first responders — fire fighters, liquidators, physicians and governments — were appropriate and probably saved tens of thousands of lives.
At first glance, the Chernobyl Forum findings would appear to have little relevance outside the former Soviet Union. Nothing could be further from the truth, particularly in the age of possible nuclear or radiological terrorism. Accessibility and rapid distribution of potassium iodide would have prevented most of the thyroid cancer cases. The experience gained by physicians in treating the 134 acute radiation sickness patients is invaluable. A lot of information has also been gained on dispersion and bio-pathways of radioactive cesium in both urban and rural environments.
Clearly established is the necessity of communicating accurate, timely and complete information to the public. Such information is needed for taking the right actions at the right time in the event of emergencies, and for recognizing and preventing the kind of long-term psychological issues that the Chernobyl accident so evidently raised.
Dr. Fred Mettler is Professor Emeritus of the Department
of Radiology of the University of New Mexico, the US Representative to the
United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)
and one of the 13 members of the International Commission on Radiological
Protection. He was the Health Effects Team Leader of the 1990 International
Chernobyl Project and has served in various capacities at international
conferences of the IAEA, World Health Organization, and other bodies.
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