High doses of ionizing radiation are dangerous for people and robots. Everyone knows about this. But some people are especially afraid of radiation; for them, the word “radiation” is almost equivalent to the word “death”. In fact, there is nothing dangerous in low doses of radiation. Moreover, radiation is a completely natural thing. It is present not only in, but even in Ecuadorian bananas.
Randel Munro back in 2011 compiled an excellent table of radiation doses, which clearly shows what radiation doses a person receives from various sources. The table has been translated into Russian. The most important thing is that it gives an understanding of perspective, that is, it allows you to compare in one picture the absorbed radiation from the same notorious eaten banana (0.05 μSv) with a lethal dose (8 Sv).
Absorbed radiation is measured in Sieverts (Sv). A large dose received over a short period of time usually causes more damage, but "accumulated" radiation also matters because it produces ongoing damage to the body's cells. Cumulative dose plays a role in issues such as cancer risk.
Randel Munroe begins his table with the simplest and most natural sources of radiation: the person in bed next to you, the banana you eat, etc. It is especially noted that the mobile phone is not included in the list of everyday sources of low doses of radiation, because it does not create ionizing radiation and does not cause Cancer.
Total dose according to everyone points of the blue table - 60 μSv. This is less than the absorbed radiation from 1 year of life in a stone, brick or concrete building (now it’s clear why people buy environmentally friendly and highly durable ones).
But even All The points in the green table are only a tiny part of the absorbed radiation that can cause slight damage to human health, see the entire table.
There is also a visual video made based on this table.
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Natural potassium consists primarily of two stable isotopes: 39 K (93.26%) and 41 K (6.73%), but potassium also contains a small amount of the radioactive isotope 40 K (0.01%). The isotope potassium-40 is beta-active and has a half-life of 1.251·10 9 years.
Despite the low content of the 40 K isotope in natural potassium and its rather long half-life, the radioactivity of potassium can be easily detected even with the help of simple instruments. In a gram of natural potassium, 32 disintegrations of potassium-40 nuclei occur every second. This corresponds to a radioactivity of 32 becquerels, or 865 picocuries.
It is believed that the radioactive decay of 40 K is one of the main sources of geothermal energy, which is released in the bowels of the Earth (the power is estimated at 44 TW). In minerals containing potassium, the isotope 40 Ar, which is a decay product of 40 K, gradually accumulates. By measuring the ratio between the isotopes 40 K and 40 Ar, the age of rocks can be measured. The potassium-argon method of dating, which is one of the main methods of nuclear geochronology, is based on this principle.
On the other hand, potassium is one of the most important biogenic elements that are necessary for all living things. Of course, along with stable isotopes of potassium, radioactive 40 K also enters living organisms. For example, due to potassium-40, about 4000 radioactive decays occur every second in the body of a 70 kg person.
A person receives a significant portion of radioactive isotopes from food (on average about 40 millirem per year or more than 10% of the total annual dose). Almost all foods contain small amounts of radioactive isotopes, but the natural level of radioactivity in some foods is noticeably higher than average. These foods include potatoes, beans, nuts and sunflower seeds. Relatively high level observed in Brazil nuts (due to the increased content of radioactive isotopes 40 K, 226 Ra, 228 Ra), the radioactivity of which can reach 12,000 picocuries per kilogram and higher (450 Bq/kg and higher).
Bananas are also among the foods with increased natural radioactivity. The average banana contains 3,520 picocuries per kilogram of weight, or approximately 520 picocuries in a 150-gram banana. The equivalent dose in 365 bananas (one per day for a year) is 3.6 millirem or 36 microsieverts. The main reason for the radioactivity of bananas is natural isotope potassium-40.
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The radioactivity of bananas has repeatedly caused false alarms in radiation detectors used to prevent the illegal import of radioactive materials into the United States.
IN nuclear energy the term "banana equivalent" is even used. The banana equivalent corresponds to the amount of radioactive isotopes that enter the body when eating one banana.
Radiation leaks from nuclear power plants are often measured in very small units, such as picocuries (one trillionth of a curie). Comparing these doses with the natural radioactivity of one banana allows you to intuitively assess the risk of leaks.
For example, after the accident at the Three Mile Island nuclear power plant, the US Nuclear Energy Commission discovered radioactive iodine in the milk of local cows in the amount of 20 picocuries per liter. This radioactivity is significantly less than in a regular banana. A glass of this milk contained only 1/75th the equivalent of a banana.
It should, however, be taken into account that such a comparison is very conditional, since the radiation of various radioactive isotopes is by no means equivalent from the point of view of biological effects. In addition, there is reason to believe that eating a banana does not increase the level of radiation in the body, since excess potassium obtained from a banana leads to the elimination of an equivalent amount of the 40 K isotope from the body through metabolism.
We all know about obvious things that are a source of radiation: nuclear power plants, microwave ovens, nuclear weapons and visiting some territories of Ukraine. However, it is also important to be aware of less obvious sources of radiation.
9. Brazil nuts
Brazil nuts are one of the most radioactive food sources in the world, but don't think a couple of nuts will give you super powers. It won't reward you, people have already tried it. As one unfortunate nut lover discovered, eating Brazil nuts can cause your feces and urine to become overly radioactive. The reason for this radioactivity is simple: the roots of the tree that bears Brazil nuts go so deep into the ground that they absorb large amounts of radium, a natural source of radiation.
8. Grand Central Station New York
Grand Central Station in New York is one of the largest train stations in the world. Those planning to visit this station will be unpleasant to learn that it is also one of the most radioactive stations. Its radioactivity is due to the walls and foundation being built from granite, a rock capable of containing natural radiation. Radiation levels at the station are so high that they exceed the levels that nuclear power plants can legally emit.
7. Evacuation signs
If you attend school or college, or work in an office, you've probably seen illuminated Exit (or Exit) signs. Since the signs are intended to guide people to safety in the event of a disaster, they are not connected to electrical network buildings - after all, in an emergency, there will most likely be no electricity. So how do they produce this light? Long life batteries? Hamsters on a wheel? Unfortunately, no: the light is emitted by the radioactive isotope of hydrogen - tritium, contained in the sign. So, if during a disaster that results in a power outage, the sign breaks, then radioactive isotope can infect the entire building and the people in it.
6. Cat litter
If, for some reason, you ever want to dive into your cat's litter box, think carefully about your decision. Besides the fact that the very thought of it is disgusting, cat litter is also one of the most common sources of radiation in our homes. This is due to one of the litter's main components, bentonite, a clay mineral that is excellent at absorbing feces and urine, but is very poor at NOT containing the residues of naturally occurring uranium and thorium that it contains. Moreover, because thousands of tons of filler end up in landfills each year, there is a danger that this radiation could eventually leak into groundwater.
5. Bananas
Bananas, like Brazil nuts, emit small amounts of radiation. But while in the case of Brazil nuts this is the result of the tree "sucking" radiation from the ground, bananas suffer from radiation due to the fact that it is in their genetic code. Before you rush to bury your bananas in leaded coffins, it's worth knowing that in order to get radiation sickness, you need to eat about 5 million bananas. So, there is no need to worry - by the time a person finishes his five-millionth banana, he will probably already become a banana himself. However, radiation from bananas can be detected by Geiger counters, and if you have a bunch of bananas in your bag when you go through the radiation sensor at customs, don't be surprised if you get stopped.
4. Granite kitchen countertop
Let's say you've already vowed to never eat bananas or Brazil nuts. Your body has become a temple dedicated to a clean, non-radioactive lifestyle. However, if your kitchen has granite countertops, there is a good chance that all the food cooked on it has been irradiated. If you still remember the story of the New York train station, you already guessed why: granite perfectly stores natural sources of radiation.
3. Cigarettes
The fact that cigarettes are harmful will not surprise anyone: after all, they talk so much about it on TV, and everything that is shown on TV is true! Many cigarettes contain these radioactive materials, like polonium-210 (the same radioactive isotope that killed Alexander Litvinenko) and lead-210 - if you were looking for a reason to quit smoking, here they are. These isotopes, which remain in the tobacco leaves throughout the cigarette manufacturing process, are released into the air as vapor when the cigarette is lit, after which the smoker inhales them into the body. Although the concentrations of these isotopes are small, over time the chemicals accumulate in the organs of heavy smokers and are thought to be linked to the development of certain types of cancer.
2. Old pottery and glassware
It's very touching that your grandmother left you all these old vases and glassware, but don't be fooled: you need to throw it all away right now, despite all the memories associated with them. Much of the pottery made before 1960 - mostly orange or red - contains high concentrations of uranium, which when added to the glaze produces that recognizable color. Likewise, if you have a glass antique with a greenish tint, it contains uranium. It is not worth mentioning that you should not drink from such devices, since in addition to radioactivity, such old porcelain is also dangerous because lead is released from it.
1. Glossy magazine paper
If a magazine publisher wants to spend more money, they print the magazine on glossy paper - mainly because it makes the magazine look better, but also because they think consumers are magpies who will want to buy something shiny. However, in order to make glossy paper, it is coated with kaolin, a white clay. Like the clay material used to make cat litter, this clay is also capable of containing radioactive elements, like uranium and thorium. This clay is also used as a dietary supplement and an ingredient in many over-the-counter medications.
Once upon a time in Bohemia, where uranium was first discovered, miners working in silver mines actively used one unusual property of mine water against diseases. It was believed that when consumed regularly, it helped reduce colds. To enhance this effect, they brought home pieces of radioactive ore and placed them in their pillows. Indeed, their runny nose completely disappeared. True, these people later died of cancer, but in those days no one had made such diagnoses. The fight against colds was apparently more urgent for miners.
This story about Bohemian miners was recalled in his lecture by the famous popularizer of atomic science and nuclear technology, teacher at the St. Petersburg State Technological Institute, Andrei Akatov. The story he tells is in many ways revealing. The fact is that we usually perceive radiation as a direct threat to life, whereas in fact its effect on the body is much more complex. As for radiation sources, it turns out that there are much more of them than many of us think.
“All objects around us, including ourselves, are necessarily radioactive,” noted Andrei Akatov. It follows that it is impossible in principle to avoid exposure to radiation.
However, in many cases this is not even necessary, since radiation in small doses can have a positive effect on the body. According to the expert, experiments conducted on animals have shown that if they are completely isolated from the effects of ionizing radiation, then their desire to eat and reproduce completely disappears. All body functions quickly fade away. Philosophically speaking, without radiation the will to live is lost. Moreover, without exposure to AI, immunity drops sharply. “If you completely remove the background radiation,” the expert notes, “then you and I will get sick much more often than this happens in the normal state.” This is why some people specifically go to radon sources. That is, they deliberately try to receive a small dose of radiation in order to “trigger” immune processes. By the way, the beneficial effects of radon baths have been known for more than two thousand years. The ancient Romans resorted to this type of treatment. The same thing happened once with the Japanese.
As Andrei Akatov showed, a huge number of objects around us have a certain radiation, and thus they contribute to the general radiation background. To do this, in fact, there is no need to wait for any accidents at nuclear power plants. Many objects, even quite ordinary ones, are “phoning”. Radioactive substances, from which we receive the main dose of radiation throughout our lives, are very often contained in a wide variety of materials and products that we use in our work. everyday life. As clear example Andrey Akatov leads the embankment of St. Petersburg. “There is a lot of radioactive potassium-40, thorium and uranium in granites and in general in rocks erupted from magma,” he clarifies. If you approach the famous Thunder Stone with a dosimeter, on which stands the monument to Emperor Peter the Great, the background radiation there is four times higher than in the city as a whole. Moreover, this background in St. Petersburg itself is even higher than in the territory of the Leningrad Nuclear Power Plant. This is due to the fact, believes Andrei Akatov, that man, due to his technogenic activities, concentrates various natural radioactive substances around himself.
The most important source of radiation in different cities - including St. Petersburg, Murmansk, Novosibirsk - is granites and asphalt. Asphalt, surprisingly, contains quite a lot of radioactive substances. “When you walk on asphalt,” says Andrei Akatov, “the radiation background here is noticeably higher than when you walk on bare ground.” By the way, the Altai Mountains, where granites come to the surface, also have an increased background radiation. This is one of the most radioactive places in our country, says Andrei Akatov. A similar situation is observed in Finland (also due to granites). This makes it noticeably different from the neighboring Leningrad region.
Radon has the greatest effect on background radiation. This is the so-called “noble” volatile gas. It is released from the soil almost everywhere - it rises along faults in the ground and quite easily penetrates into our homes, giving us about half of the annual radiation dose. This happens all over the planet – somewhere a little more, somewhere a little less. Radon usually enters the first and second floors of buildings (it does not rise higher).
Another source of radiation is phosphate fertilizers. Radioactive substances inevitably concentrate during the processing of phosphate ores, and therefore all superphosphate undergoes mandatory radiation control. “Otherwise, you can overdo it and add excessive amounts of uranium and thorium to your plants,” the expert notes.
Separate topic - building materials. The most radioactive building material is phosphogypsum, obtained by processing the mentioned phosphate ores. According to the expert, if your house is built using such material, then you may be in a radiation hazard zone. In this case, it is simply necessary to monitor the radiation situation in your apartment and throughout the building. Some aerated concrete also “sounds”. Once a village was built from similar materials in Finland. As a result, about a hundred houses had to be urgently resettled, since an inspection revealed an increased background radiation. Some building materials emit radon intensely, which can cause radiation levels to rise slightly. In this case, Andrey Akatov believes, it is necessary to ventilate the apartment well and regularly carry out wet cleaning. These simple measures provide you with normal protection from increased radiation.
Natural coals used in thermal power plants also contain radioactive substances. And if carbon dioxide evaporates during their operation, then the opposite happens with radioactive substances - they are concentrated in ash. The ash, in turn, accumulates on the territory of the stations. Therefore, surprisingly, the background radiation may be higher near urban thermal power plants than near nuclear power plants.
Even man himself is a carrier of radioactive substances. We are talking, first of all, about potassium-40 (K-40). Potassium is known to help the functioning of the heart and is therefore necessary for humans. K-40 is a radioactive isotope. Because of it, in every person, according to Andrei Akatov, four thousand radioactive decays occur every second. Accordingly, we irradiate both ourselves and our neighbors. When people live together, they increase the total radiation dose by about one percent.
Finally, the most interesting thing. “Nuclear scientists,” explains Andrei Akatov, “have come up with a kind of “banana” equivalent of radiation. Bananas contain large amounts of potassium. Therefore, this popular fruit can easily serve as a radioactivity standard.” Interestingly, when banana shipments cross border checkpoints radiation monitoring, then a false alarm is often triggered due to their high natural radioactivity.
How radioactive is a banana? According to simplified calculations, the dose we receive during fluorography is equal to five hundred bananas. In principle, the expert believes, any radiation can be measured in bananas. Although bananas are far from the most radioactive product. Brazil nuts have even higher radioactivity. This plant, in addition to everything else, manages to “draw” into itself earth's crust radium-226. Today, Brazil nuts are considered the most radioactive of all known products. Somewhere nearby there are mushrooms, some cereals and greens (especially celery).
However, you should not be afraid, since the radioactivity of these products is many times lower dangerous level. Thus, the annual radiation dose received by residents of the Novosibirsk region (4 mSv) is equivalent to forty thousand bananas. That is, it is necessary to consume a whole container of these tropical fruits in order to get closer to the usual (and quite normal) indicators for our region.
We all know about obvious things that are a source of radiation: nuclear power plants, microwave ovens, nuclear weapons and visiting some territories of Ukraine. However, it is also important to be aware of less obvious sources of radiation.
9. Brazil nuts 
Brazil nuts are one of the most radioactive food sources in the world, but don't think a couple of nuts will give you super powers. It won't reward you, people have already tried it. As one unfortunate nut lover discovered, eating Brazil nuts can cause your feces and urine to become overly radioactive. The reason for this radioactivity is simple: the roots of the tree that bears Brazil nuts go so deep into the ground that they absorb large amounts of radium, a natural source of radiation.
8. Grand Central Station New York
Grand Central Station in New York is one of the largest train stations in the world. Those planning to visit this station will be unpleasant to learn that it is also one of the most radioactive stations. Its radioactivity is due to the walls and foundation being built from granite, a rock capable of containing natural radiation. Radiation levels at the station are so high that they exceed the levels that nuclear power plants can legally emit.
7. Evacuation signs
If you attend school or college, or work in an office, you've probably seen illuminated Exit (or Exit) signs. Since the signs are intended to guide people to safety in the event of a disaster, they are not connected to the building's electrical network - since there would most likely be no electricity in an emergency. So how do they produce this light? Long life batteries? Hamsters on a wheel? Unfortunately, no: the light is emitted by the radioactive isotope of hydrogen - tritium, contained in the sign. So, if a sign were to break during a disaster that resulted in a power outage, the radioactive isotope could contaminate the entire building and the people in it.
6. Cat litter
If, for some reason, you ever want to dive into your cat's litter box, think carefully about your decision. Besides the fact that the very thought of it is disgusting, cat litter is also one of the most common sources of radiation in our homes. This is due to one of the litter's main components, bentonite, a clay mineral that is great at absorbing feces and urine, but is very poor at NOT containing the naturally occurring uranium and thorium residues it contains. Moreover, because thousands of tons of filler end up in landfills each year, there is a danger that this radiation could eventually leak into groundwater.
5. Bananas
Bananas, like Brazil nuts, emit small amounts of radiation. But while in the case of Brazil nuts it is the result of the tree sucking radiation out of the ground, bananas suffer from radiation because it is in their genetic code. Before you rush to bury your bananas in leaded coffins, it's worth knowing that in order to get radiation sickness, you need to eat about 5 million bananas. So, there is no need to worry - by the time a person finishes his five-millionth banana, he will probably already become a banana himself. However, radiation from bananas can be detected by Geiger counters, and if you have a bunch of bananas in your bag when you go through the radiation sensor at customs, don't be surprised if you get stopped.
4. Granite kitchen countertop
Let's say you've already vowed to never eat bananas or Brazil nuts. Your body has become a temple dedicated to a clean, non-radioactive lifestyle. However, if your kitchen has granite countertops, there is a good chance that all the food cooked on it has been irradiated. If you still remember the story of the New York train station, you already guessed why: granite perfectly stores natural sources of radiation.
3. Cigarettes
The fact that cigarettes are harmful will not surprise anyone: after all, they talk so much about it on TV, and everything that is shown on TV is true! Many cigarettes contain radioactive materials such as polonium-210 (the same radioactive isotope that killed Alexander Litvinenko) and lead-210 - if you were looking for a reason to quit smoking, here they are. These isotopes, which remain in the tobacco leaves throughout the cigarette manufacturing process, are released into the air as vapor when the cigarette is lit, after which the smoker inhales them into the body. Although the concentrations of these isotopes are small, over time the chemicals accumulate in the organs of heavy smokers and are thought to be linked to the development of certain types of cancer.
2. Old pottery and glassware
It's very touching that your grandmother left you all these old vases and glassware, but don't be fooled: you need to throw it all away right now, despite all the memories associated with them. Much of the pottery made before 1960—mostly that which is orange or red in color—contains high concentrations of uranium, which when added to the glaze produces that recognizable color. Likewise, if you have a glass antique with a greenish tint, it contains uranium. It is not worth mentioning that you should not drink from such devices, since in addition to radioactivity, such old porcelain is also dangerous because lead is released from it.
1. Glossy magazine paper
If a magazine publisher wants to spend more money, they print the magazine on glossy paper - mainly because it will make the magazine look better, but also because they think consumers are magpies who will want to buy something shiny. However, in order to make glossy paper, it is coated with kaolin, a white clay. Like the clay material used to make cat litter, this clay can also contain radioactive elements such as uranium and thorium. This clay is also used as a dietary supplement and an ingredient in many over-the-counter medications.
