Natural radioactivity is present everywhere in our lives, it is part of the human environment. This phenomenon was discovered in 1896 by a French scientist by the name of A. Becquerel, who discovered a source of natural radioactivity quite by accident during an experiment to study the effects on a photographic plate, which was wrapped in black paper, fluorescent zinc sulfide.
What is natural radioactivity? This is the transformation of the atomic nuclei of one chemical element into the nuclei of atoms of another element. This process is always accompanied by radioactive radiation. A great contribution to the study of this issue was made by the outstanding physicist Maria Sklodowska-Curie. It was she who in 1898 discovered the elements of radium and polonium.
Physicists have proved that natural radioactivity is not subject to change under the influence of external conditions. It can be of two types: proton, as well as two-proton.
Natural radioactivity includes several components. These include: cosmic radiation, radioactive substances that are constantly in the earth, as well as a source of radiation, which is found in building materials, in food and water.
If calculated as a percentage, then the natural radioactivity can be represented as follows: 73% - is associated with the influence of natural radiation sources that surround us everywhere, 13% - is created due to medical procedures (the most significant fluoroscopy), and 14% of radiation accounted for by rays from space.
Solar radiation has tremendous power, but the Earth reliably protects the Earth from it, however, the higher the distance from the Earth's surface, the stronger the effect of cosmic radiation. Scientists observe a doubling of its action every 1000 meters. For example, during an airplane’s flight, when it gains a height of about 10,000 meters, the level of radiation in the cabin exceeds the natural level by almost 10 times.
Flashes that periodically appear on the Sun are also a powerful component of the "natural" radiation background. The following sources are particles that are part of building materials, waste from the combustion of coal, as well as phosphate fertilizers.
How is the level of natural radioactivity distributed on the planet? Scientists have calculated that it varies in the amount of 5 -20 microroentgen per hour. At the same time, the question for mankind arises of how harmful such an indicator is for the life of people living on our planet.
On this issue, the statements of scientists are ambiguous. Some people think that the damage from radiation is insignificant, while others claim that it causes serious diseases and mutations, but it is obvious that this issue requires more in-depth research.
A person practically can not significantly affect the radioactive background, therefore, it is necessary to protect oneself from the influence of those negative factors that exceed permissible values.
Radioactivity units :
- 1 rem = 0.01 Sievert;
- 1 mber = 0.01 milli sievert.
Cosmic radiation is equivalent to an annual dose of 30 mbar (300 μSv), but, for example, at an altitude of approximately 10 km, the radiation dose will be already 100 times larger. The level of radiation differs on different continents and in individual countries. In France, the United States and Japan, it is 30-60 millibars per year. The population of these prosperous countries receives annually 100-150 mber of radiation due to the available background. In Russia, this indicator averages 65 mber / year.
The ways in which radioactive substances enter the body can be very diverse. The most common of them: through the lungs, with food, through the skin by absorption. The increased radioactive background negatively affects the human body. Hazardous substances are evenly distributed throughout the body of the victim. If we take into account all the sources of radionuclides, then the annual dose for humans is on average 135 mber.