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