Translated material
Expert: exceeding standards for the content of radioactive substances in food
Japanese Prime Minister Naoto Kan instructed the authorities of Fukushima Prefecture to introduce a trade ban on 11 types of vegetables. The government said radiation levels exceeding legal limits were found in vegetables from Fukushima and dairy products from neighboring Ibaraki prefecture. Japan's Ministry of Health has advised the public not to consume vegetables and milk from these prefectures. Meanwhile, European media report that a radioactive cloud with radioactive particles from a Japanese nuclear power plant has reached Iceland.
Ravil Bakin, head of the laboratory of decision support systems in crisis situations, IBRAE RAS:
The standards for the content of radioactive substances in both water and food are quite strict, especially for children. If these standards are slightly exceeded, then this is more reinsurance than a real threat. The isotope of iodine is quite short-lived. In 2-3 weeks, its content will be much lower than now, and the issue of iodine will be removed from the agenda. And naturally, in the event of such accidents, leafy vegetables, those that grow in open ground, cause a certain concern. But this problem will also be solved due to the natural breakdown of iodine.
As for drinking water in Tokyo, unfortunately, we do not know the actual sources of Tokyo's water supply, since, according to my information, such information was received only for one of the districts of Tokyo. And often such information is not always verified and reliable. As for the appearance of radioactive substances in Iceland, we can say that wind transfers occur throughout the entire territory of the earth and some portion always reaches any point on the earth. Therefore, there is nothing surprising in this, but these are such microscopic values that sometimes not all instruments can even record them. High-precision measurements are needed only to record the fact itself and that’s all. There is no need to talk about any impact on people’s health.
Radiation safety standards are extremely stringent. That is, the risk that comes with consuming such water is also extremely low. This is more of a reinsurance and more of a subjective approach out of fear that radiation is a very serious matter. Although there are probably more dangerous substances in the same drinking water in Tokyo than the iodine isotope. After 3 weeks, the iodine will simply disintegrate naturally and will be gone.
Today, the radiation pollution standards here and abroad are practically close, since both ours and foreign standards are based on the basic principles proposed by the International Committee on Radiation Protection. Based on 1 millisievert per year per population, the derived concentration levels of a particular radionuclide are calculated, and these standards are, in principle, the same in all countries that have adopted the ICRP recommendations, the so-called ICRP pollution standards.
The potential danger of radionuclides to health is a probabilistic value. While there are such real values, real cases, to say that a person has eaten this or that radionuclide so much and then to actually record any harm to health - there are simply no such data. This is all done at the level of calculated values and assumptions. And in order to get statistics, to say that people ate so much and so much, and out of such and such a number of people so many people got sick - there is simply no such data. It is generally believed, of course, that one millisievert is the annual dose recommended by the International Committee on Radiation Protection. But, at the same time, there is confirmed data that a dose of less than 10 millisieverts does not particularly affect health in any way. A dose of up to 100 millisieverts does not lead to deterioration in health or the occurrence of any harmful effects - these are the current recommendations of the ICRP.
The fact is that in addition to man-made radionuclides that are produced at nuclear power plants and nuclear industry enterprises, there are natural radionuclides that are contained in the earth and determine the natural background throughout the Earth. First of all, this is, of course, radon. No matter how strange it may be, with an acceptable dose for the population of 1 millisievert, approximately 3 millisieverts are the annual dose from radon per person. This is just a natural background. It is determined by radin, potassium, and uranium by their decay products. If in Russia the background is somewhere around 0.1-0.2 microsieverts per hour, then there are areas in India and Brazil where the natural background is several hundred times higher. And people have been living there peacefully for a long time. The natural background is determined by how much natural nuclides are in certain soils. For example, if the average background in St. Petersburg is about 0.2 millisieverts, then in the area of the granite embankment it is 2 times higher due to the fact that granite contains many natural radionuclides. And all this is determined by natural radionuclides.