Dr. Tsubokura's Radiation Lecture Vol.63

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

125. No difference between artificial and natural radiation substances

Japanese populations are exposed to approximately 2.1 millisieverts of radiation annually from various radioactive substances in daily life. Furthermore, about one-third of radiation exposure is caused by ingesting the natural radioactive substance, called polonium, found in seafood.

As I have repeatedly explained in the series, the extent of the exposure dose determines the impact of radiation on health; the safety of radiation exposure is not determined by whether it is from natural or artificial sources. The above amount of polonium will not negatively affect our health. However, it could be fatal if we receive a 1,000 to 10,000 times higher level than what we usually receive at once, even though polonium is a natural radioactive substance.

In fact, about 10 years ago, a publicly well-known person in British society was poisoned with a large amount of polonium. Due to this incident, the crime scene and its surroundings were also contaminated, requiring long-term monitoring.Of course, we are not at risk of being exposed to such a substantial level of natural radioactive substance in daily life. In this article, I introduced an unusual example to demonstrate that the extent of the exposure dose determines the impact on our health, not whether the source of radiation is artificial or natural.

126. Tobacco also contains poloniumThe Energy Level of Tritium Is Significantly Small

Japanese populations are exposed to approximately 2.1 millisieverts of radiation annually from various radioactive substances in daily life. Furthermore, about one-third of radiation exposure is caused by ingesting the natural radioactive substance, called polonium, found in seafood.

This substance is also found in tobacco leaves. It is absorbed from the soil and fertilizer used to grow tobacco leaves; these leaves also have many sticky hair fibers on the surface, and these fibers collect radioactive substances from the air.

Of course, the fact that tobacco contains radioactive substance itself is not a problem, but its dose is a matter of concern. Tobacco leaves are not the only crops that contain polonium. Although smoking tobacco causes radiation exposure of lung tissues, the exposure dose of polonium for smoking 20 cigarettes a day for one year will be approximately the same as or slightly higher than that of a single chest x-ray.It is a well-known fact that smoking causes lung cancer, but its harm is not limited to chemical substances.

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The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, on 4th and 11st June 2017 was reproduced for MRIC Global under the author's permission.