Dr. Tsubokura's Radiation Lecture Vol.19

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

37. The current level of exposure is lower than the average exposure level in the 1960s

Nuclear weapons tests, which have been conducted several hundred times since the 1950s, have released significant levels of radioactive substances worldwide. Findings from a post-World War Ⅱ survey showed that the radioactive cesium was detected in the bodies and urine of Japanese people and in food made in Japan.

On average, several hundred becquerels of radioactive cesium 137 were detected in Japanese adult males in the mid-1960s. By contrast, the findings of an investigation that examined the level of internal exposure among adults living in Minamisoma City in 2015 showed that people who had the same internal radiation level as the average level in the mid-1960s were less than 1% of the population.

Even in the examination from fall to winter 2011 when the influence of the nuclear power plant accident remained, the rate of adults with internal exposure exceeding the average level detected in the mid-1960s was approximately 10%.

The Fukushima Daiichi nuclear disaster caused the release of radioactivity into the environment, but from these data, levels of human exposure were not as high as previously thought.

38. The relationship between the diet of reindeer and internal radiation exposure

Radioactive substances emitted from the Chernobyl nuclear accident that occurred 30 years ago reached the Scandinavian Peninsula, and these Northern European countries became contaminated.The Sami ethnic groups living in these regions eat reindeer as their primary source of protein.

However, the reindeer meat tends to have a high level of radiation contamination because they feed on moss. As Sami ethnics are living on animals that are easily contaminated, the level of their internal radiation contamination was severe. The average cesium levels detected in their bodies was several times higher than the maximum level of those of who consistently ate highly contaminated food that did not undergo inspection in Fukushima prefecture after the 2011 Fukushima nuclear accident.

The level of radioactive contamination in food in Fukushima is entirely different from that of the Chernobyl accident. It also should be noted that contamination levels differ in each type of food.Some specific types of food tend to have a higher dose of radiation.

It is fortunate that rice, which is a staple of our diet, does not absorbs radiation easily. ---------------------------------------------------------------------------------------------------------------

The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, on September 20th ,27th 2015, and was reproduced for MRIC Global under the author's permission.