Dr. Tsubokura's Radiation Lecture Vol.20

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

39. Radiation exposure and the health of Sami ethnics

The previous article explained that after the Chernobyl nuclear power plant accident, the consumption of reindeer meat, which is a type of food easily contaminated with radiation, resulted in increased internal exposure among people of Sami ethnicity.

All of the surveys that investigated the cancer risk of the Sami ethnic group showed that they have lower cancer risk and cancer mortality rates than other populations.These results do not indicate that radiation exposure would be good for your health or that we can tolerate a high level of radiation.

However, the results of these surveys suggest the importance of sustaining an ordinary, stable routine to maintain health.The reason that we advise you to avoid unnecessary radiation exposure is to maintain good health, but a healthy life is not achieved through only a reduction of radiation exposure.

Living environments and lifestyle habits are the major factors that contribute to good health.

40. Determining the reference value of radiation to ensure food safety

Radiation detectors have a lower limit in measuring levels of radiation contamination.If the radiation contamination of measured food is below this value, the result of the test will be “undetected.”Thus, it is natural for you to be concerned that there could be some contamination even when detectors cannot sense it.

However, the same problem emerges when we are dealing with many other kinds of chemical substances as well.Enormous time and effort would be needed to bring the lower detection limit very close to zero, but we would never be able to prove a contamination level of 0.

For example, let’s say the detector has successfully confirmed that the contamination of pesticide in food is below 1 gram. However, there will be no end if it continues as “how about 0.1 gram?” and “How about 0.01 gram?”To solve this problem, we normally set reference values that guarantee the safety of food.

With regard to detecting radiation contamination in food, the lower detection limit of the devices normally ranges from 10 to 20 becquerel/kg. This value could change slightly depending on the type of instrument, the time interval for the measurement and the surrounding environment, such as temperature and humidity.

In any case, the detectors are able to detect a lower level of radiation contamination than food’s reference value. ---------------------------------------------------------------------------------------------------------------

The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, on October 4th ,11th 2015, and was reproduced for MRIC Global under the author's permission.