Chernobyl, Three Miles Island and thyroid cancer

Nuke Those Fears! By Ruth Kava, Ph.D., R.D.
Greens dismiss nuclear energy based on little more than greatly exaggerated depictions of the supposed dangers and difficulties of its use.
American Council on Science and Health, Jan 27, 2009

Excerpts:

The environmental mantra these days has two main components -- clean energy and green (sustainable) energy -- anything but oil and coal. Proponents strongly encourage the development of solar and wind energy, neither of which is ready yet for widespread commercial use. But they ignore or downplay the use of a well understood and already commercialized technology -- nuclear energy -- based on little more than greatly exaggerated depictions of the supposed dangers and difficulties of its use.

One fear that has been widely promoted is that of large-scale accidents in nuclear power plants. Anti-nuclear activists point to two examples of that -- the explosion at the Russian Chernobyl reactor in 1986, and the partial meltdown of the fuel rods at the Three Mile Island reactor in 1979.

The Chernobyl explosion was due to errors made by the operators during a test and a lack of adequate safety features and procedures that could have prevented such errors. It will surprise many that, with the exception of workers who were on the scene and received massive acute doses of radiation, there has been no evidence of increased radiation-caused mortality. In contrast to the Chernobyl plant, modern nuclear facilities have redundant safety features to prevent such errors.

Although it has also been used as an example of a large-scale accident, there was actually little release of radioactivity from the Three Mile Island reactor -- even though about half of the fuel melted. The level of radioactivity received by the surrounding area was not significantly greater than that normally supplied by natural background sources. In other words, the containment precautions were effective. Of course, the anti-nuclear fanatics' propaganda pays no attention to these simple facts.

Another fear that has been widely promoted is that release of radioactivity from a nuclear plant -- specifically the radioactive iodine, I131 -- would cause thyroid cancer in exposed children. This fear actually has some biological basis in that the thyroid gland avidly takes up iodine. It can be prevented from absorbing the radioactive iodine, however, by giving a large dose of non-radioactive iodine. An even simpler preventive measure: avoid drinking milk for a week or two after such an (unlikely) event. Of course prevention of I131 release is a much better option.

It is true that a year after the Chernobyl accident screening studies revealed an increased occurrence of thyroid cancer in exposed children. However, many scientists have questioned whether this was really due to the Chernobyl-related exposure, since thyroid cancer typically has a latency period of thirty years. Further, it is important to note that prior to the explosion, there was very little screening of children in the Chernobyl area -- but around 90% were screened afterwards. This fact alone very likely contributed to the increased incidence observed. In addition, the incidence of thyroid cancer was actually lower in the highly contaminated region than in the general Russian population.

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Dr. Ruth Kava is Director of Nutrition at the American Council on Science and Health (ACSH.org, HealthFactsAndFears.com).