Guide-scientific.com debunks scientific myths and fights common misconceptions. We asked our experts to comment on established ideas about radioactive substances and their effects on humans.
Lead walls protect against radiation
Only partly true.
In explaining this belief, two points need to be made. The first is that there are several types of radiation associated with different types of emitted particles.
There is alpha radiation – these are the nuclei of helium-4 (He-4) atoms. They very effectively ionize everything around. But it’s just your clothes that stop them. That is, if you have a source of alpha radiation in front of you and you are wearing clothes, wearing glasses, then nothing bad will happen to you.
There is beta radiation – these are electrons. Electrons have lower ionizing power, but this is more deeply penetrating radiation. However, it can be stopped, for example, with a small layer of aluminum foil.
And finally, there is gamma radiation, which, when compared at the same intensity, has the least ionizing power, but it has the best penetrating power and therefore represents the greatest danger. That is, no matter what kind of protective suit you wrap yourself in front of a gamma source, you will still receive a dose of radiation. It is protection from gamma radiation that is associated with lead cellars, bunkers, and so on.
With the same thickness, a layer of lead will be slightly more effective than the same layer of, for example, concrete or compacted soil. Lead is not a magical material. An important parameter is density, and lead has a high density. It was because of its density that lead was indeed often used for defensive purposes in the middle of the 20th century, at the beginning of the nuclear age. But lead has a certain toxicity, so today, for the same purposes, they prefer, for example, simply thicker layers of concrete.
Radiation is of natural origin. For example, solar radiation also generates background radiation. In southern countries, where the sun is very bright and hot, the radiation natural background is quite high. Of course, it is not harmful to humans, but it is higher than in northern countries.
In addition, there is also cosmic radiation, which from distant space objects reaches our atmosphere.
After all, what is radiation? High-energy particles bombard atoms in the atmosphere and ionize them. In the human body, particles also ionize atoms, knock out electrons from shells, can destroy molecules, and so on. The nucleus of an atom is unstable, it can emit certain particles and go into a stable state. Can emit alpha radiation, can emit beta radiation, can emit gamma radiation. Alpha is charged helium nuclei, beta is electrons, gamma is electromagnetic radiation. This is radiation.
Particles fly everywhere and always. That is, there is a natural radiation background. Sometime it becomes harder due to a brighter sun or incoming radiation from stars, sometime less. It happens that a person increases the radiation background by building a reactor or an accelerator.
Iodine protects against radiation contamination
As such, iodine or its compounds are completely unable to withstand the negative effects of radiation. Why do doctors recommend taking iodine after man-made disasters with the release of radionuclides into the environment? The fact is that if radioactive iodine-131 enters the atmosphere or water, it very quickly enters the human body and accumulates in the thyroid gland, dramatically increasing the risk of developing cancer and other diseases of this “delicate” organ. Having “filled up” the iodine depot of the thyroid gland in advance, it is possible to reduce the capture of radioactive iodine and thus “protect” its tissue from the accumulation of a radiation source.
The fact that the time has come to massively take iodine, for example, in connection with an accident at a nuclear power plant or the threat of a nuclear explosion, should be reported to citizens by the Ministry of Emergency Situations. In this case, it is better to have purified potassium iodide in tablets of 200 micrograms. If there is no threat of radioactive iodine-131 entering the environment, you should never take iodine on your own, since it, taken in a high dose, can cause serious damage to the thyroid tissue. The same, incidentally, applies to other radioprotectors. As a doctor, I observed in one provincial town an “epidemic” of vomiting, weakness, and muscle and abdominal pain caused by the massive intake of megadoses of various vitamins, an iodine alcohol solution, and other substances after a false report of an explosion at a nearby nuclear power plant.
Radiation exposure leads to mutations
In fact, radioactive radiation can lead to various damages to the DNA helix , and if both of its strands are damaged at the same time, then genetic information can be completely lost. To restore gene integrity, the DNA repair system can fill in the damaged area with random nucleotides. This is one way for a new mutation to appear. If the DNA damage is large-scale, then the cell can “decide” that it cannot survive with so many mutations, so it decides to commit suicide – to embark on the path of apoptosis . By the way, this is partly the basis of the effect of radiation therapy of malignant neoplasms: even cancer cells can be “convinced” to start apoptosis when a large amount of damage is introduced into their DNA.
But we must remember that people are quite well protected from the effects of background radiation, which has been present throughout the history of the Earth. Background radiation rarely damages DNA strands, and if one of the two strands is damaged, it can always be repaired using a backup second strand. Much more harm to the body can be caused by ultraviolet radiation, the direct impact of which on unprotected skin can cause malignancy (that is, entry into the path of “cancerous degeneration”) of skin epithelial cells. In the worst case, this can lead to the development of melanoma , until recently (before the discovery of immunotherapy) was considered the “queen of tumors” due to a very poor prognosis.
Radioactive substances glow
Only partly true.
The glow associated with radioactivity is called the word “radioluminescence”, and it cannot be said that this is a very common phenomenon. Moreover, it is usually caused not by the glow of the radioactive material itself, but by the interaction of the emitted radiation with the surrounding material.
It is quite obvious where this idea came from. In the 1920s and 1930s, when there was a peak of public interest in radioactive materials in various household appliances, medicines, and so on, paint, which included radium, was used for clock hands and coloring numbers. Most often, this paint was based on zinc sulfide mixed with copper. Radium impurities, which emitted radioactive radiation, interacted with the paint so that it began to glow green.
A significant number of those watches and decorative objects that have come down to us continued to glow green because they remained radioactive. They were quite widespread, especially in the US and Europe.
In general, the phenomenon of radioluminescence, firstly, is not so common, and secondly, luminescence can also be of a completely different nature. Bioluminescence is a special case of luminescence, like radioluminescence. Glow-in-the-dark plants or fireflies are luminescence, which has nothing to do with radiation.
We can also recall that a number of uranium salts, which, along with plutonium in the public mind, is associated with the concept of radioactivity, are green. But this has nothing to do with the formation of a green glow. In the vast majority of cases, no visible light is emitted during radioactive decay. And the “green glow” is usually associated not with the glow of the radioactive material itself, but with the interaction of radiation with the surrounding material.