You can’t see it, smell it, or hear it. But radiation is everywhere in our environment. Even in our bodies. Radioactivity is part of nature. Radioactivity has been around since the beginning of the world, but it was not discovered until the end of the 19th century. Century. In the meantime it is one of the best researched environmental phenomena, not least because it can be measured so easily. In common parlance, the name "radioactive radiation" has become a household word Although, strictly speaking, it is not the radiation that is radioactive, but the substance that emits the radiation: unstable atomic nuclei that decay spontaneously or split through human intervention, transforming into other atomic nuclei and thereby emitting ionizing radiation.
The dose makes the difference
Low radiation doses are tolerable. Finally, life on earth has been exposed to natural radioactive radiation for billions of years. In higher doses, however, radioactive radiation can damage living cells. Very high radiation doses have a lethal effect. Diseases such as cancer and changes in genetic makeup occur more frequently in living beings that have been strongly irradiated. The decisive factor for the effect of radioactive radiation on humans, animals and plants:
- how long a body is exposed to the radiation;
- how strong this radiation is;
- and what kind of radiation it is (alpha, beta or gamma radiation);
- how sensitive an irradiated body part is;
- whether a radioactive substance has been absorbed into the body or whether the radiation hits us from outside.
Radioactivity is similar to alcohol or many other substances: One or two glasses of wine per day are quite digestible, even over a long period of time. On the other hand, anyone who drinks a bottle of schnapps in one go can die of alcohol poisoning. Any substance can be harmful to health- it is only a question of quantity. In the right dose, on the other hand, many "poisons" become and numerous radioactive substances are also used in medicine to cure diseases.
We live with radioactivity
Radiation from natural and technical sources differs neither in its effect nor in its danger. Therefore, natural radioactivity sets a reliable standard for the safe handling of technically generated radiation.
The effect of a radiation dose on living beings is expressed in the unit of measurement Sievert (formerly in Rem). In Switzerland, the average radiation exposure per person is around 5.6 millisieverts (thousandths of a sievert, mSv) per year, with large individual variations depending on where you live.
Three quarters of this radiation dose is of natural origin: cosmic and terrestrial radiation from soil and rock, and radiation from radon gas. This is a naturally occurring decay product of uranium in the soil that can accumulate in living spaces. A further 21 percent comes from medicine and only 0.01 percent from technical applications. Practically no radioactive substances are released into the environment from Swiss nuclear facilities. Only people who live in close proximity receive minimal and wholly insignificant doses. They are about 400 times smaller than the natural dose of radiation.
Radon-222 and its derivatives in living and working spaces provide the largest dose contribution to the population.
Technically generated radiation has also become indispensable for numerous applications in medicine, industry, science and environmental research. Radioactivity is part of our everyday life.
Big differences from place to place
Natural radiation levels vary from place to place, depending on geology and elevation. In the Alps it can be up to twice as high as in the midlands. Because cosmic radiation increases with altitude, even a short vacation in the mountains will give you a higher dose than a whole year in the vicinity of a nuclear power plant. The same goes for a singleoversea flight. Aircrew actually absorb up to seven additional millisieverts (mSv) per year of natural radiation.
The composition of the underground and the altitude determine the natural radiation.
The radiation cans in Switzerland are completely harmless. In India, Brazil and Iran, there are areas where people absorb up to 50 times higher natural radiation doses per year than in Switzerland due to the bedrock underground. In Switzerland and the EU, 20 mSv per year is the legal limit for personnel exposed to radiation in medicine and technology, and 50 mSv in the USA. The following table will help you to better classify radiation doses: