Author: Masaharu Tsubokura M.D., PhD.

Editor: Yudai Kaneda

325  No Genetic Effects from Atomic Bomb Exposure

May 1, 2021

More than 75 years have passed since the atomic bombings of Hiroshima and Nagasaki. Recently, the latest report was released on the genetic effects of the children whose parents were exposed to radiation due to the atomic bombings of Hiroshima and Nagasaki (the so-called second generation exposed to radiation).

The relationship between parental exposure to the atomic bombs and congenital anomalies in offspring has been reported three times in the past, in 1956, 1981, and 1990. However, with the increased interest in the genetic effects of radiation after the Fukushima nuclear power plant accident, the fourth report was made after reviewing the latest radiation dose assessment and calculation methods.

This report examines the relationship between parental exposure to radiation and disability and premature death in about 70,000 newborns studied between 1948 and 1954. The previous three surveys did not show any genetic effects of radiation exposure, and the present results do not significantly change that conclusion from the previous three surveys.

The amount of radiation that people were exposed to due to the atomic bombing is very different from that of this nuclear accident.

The genetic effects of the radiation from this nuclear accident, including the study results conducted 35 years after Chernobyl that were introduced last week, are not as alarming as they might seem.

326  Internal Exposure Revised Downward

May 8, 2021

International organizations have been releasing evaluation reports on radiation exposure and its health effects due to the recent nuclear accident. One of the most representative reports is the one United Nations Commission (UNSCEAR) issued.

The report’s latest version, the “2020 Report,” was released in March 2022, and the results this time regarding the amount of internal exposure food caused were significantly revised downward (smaller values) compared to the previous 2013 report.

The previous report estimated the exposure dose for each radiation exposure pathway based on the experience of past accidents, for example, if the contamination of food is XX becquerels and we eat about XX grams of it per day, the exposure dose is XX sievert.

On the other hand, as the results of the surveys conducted over the past 10 years show, due to the effects of various countermeasures, radioactive materials have not been detected in most of the foods we eat on a daily basis, and as a result, whole-body counter tests rarely detect them anymore.

This year's report is based on many figures measured after the Fukushima nuclear accident, thus the results were lower than the previous estimates and more realistic.

Based on these exposure results, the UN report concludes that it is unlikely that health effects such as increased cancer will be seen in the future directly resulting from exposure.


The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, on 1 and 8 May 2021 was reproduced for MRIC Global under the author's permission.

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