Radon baths: can radiation be beneficial? Why is radon gas dangerous?

A little preface.

In my daily work, I have to deal with representatives of various strata of our society - from ordinary people to major leaders, and people who are called “power holders.” And in most cases, as sad as it is for me, when the conversation turns to the research and measurements I conduct, I hear the same reasoning: “Why are we forced to measure radiation? We don’t have Chernobyl, we don’t have an operating nuclear power plant nearby... It’s a waste of money and time.” Such reasoning, especially from the lips of high officials of administrations at various levels, from the city level and above, causes bewilderment. I am aware that radiation hygiene, radiology and other nuclear physics are a subject in the everyday life of most people, to put it mildly, useless... But gentlemen, leaders, at least what concerns people’s health (and yours, by the way, too) is necessary know! At least the basics. Much of the “credit” for our general “radiological ignorance” belongs to the media. Articles about the poisoning of someone in England with polonium and the discovery of Fukushima radioiodine in the Czech Republic are welcome. And about everyday things that concern every person every day - this, apparently, is of little interest to journalists. Therefore, to the best of my modest strength and the modest capabilities of my small site, I will try to talk about things simpler and more boring than spy passions with murders with radioactive elements and the like.

“...more than half the annual dose from all
natural sources of human radiation
receives through the air, irradiating with radon
your lungs while breathing"
SOROS EDUCATIONAL JOURNAL, VOLUME 6, No. 3, 2000

So, our conversation will focus on radon. What is radon? Let's turn to Wikipedia:

Radon - an element of the main subgroup of the eighth group, the sixth period of the periodic system of chemical elements of D.I. Mendeleev, with atomic number 86. Denoted by the symbol Rn (Radon). The simple substance radon under normal conditions is a colorless inert gas; radioactive and may pose a danger to health and life. At room temperature it is one of the heaviest gases. The most stable isotope (222Rn) has a half-life of 3.8 days.

The English scientist E. Rutherford noted in 1899 that thorium preparations emit, in addition to α-particles, some previously unknown substance, so that the air around the thorium preparations gradually becomes radioactive. He proposed to call this substance an emanation (from the Latin emanatio - outflow) of thorium and give it the symbol Em. Subsequent observations showed that radium preparations also emit a certain emanation, which has radioactive properties and behaves like an inert gas.

Initially, the emanation of thorium was called thoron, and the emanation of radium was called radon. It was proven that all emanations are actually radionuclides of a new element - an inert gas, which corresponds to atomic number 86. It was first isolated in its pure form by Ramsay and Gray in 1908, they also proposed to call the gas niton (from the Latin nitens, luminous ). In 1923, the gas was finally named radon and the symbol Em was changed to Rn.

Finding in nature:

It is part of the radioactive series 238U, 235U and 232Th. Radon nuclei constantly arise in nature during the radioactive decay of parent nuclei. Due to its chemical inertness, radon relatively easily leaves the crystal lattice of the “parent” mineral and enters groundwater, natural gases and air. Since the longest-lived of the four natural isotopes of radon is 222Rn, it is its content in these environments that is maximum.

The concentration of radon in the air depends, first of all, on the geological situation (for example, granites, which contain a lot of uranium, are active sources of radon, while at the same time there is little radon above the surface of the seas), as well as on the weather (during rain, microcracks, which radon comes from the soil are filled with water; snow cover also prevents radon from entering the air). Before the earthquakes, an increase in radon concentration in the air was observed, probably due to a more active exchange of air in the ground due to an increase in microseismic activity.

Already from this dry information it can be understood that radon, as a gas of natural origin, is present everywhere and always. That is, theoretically, living organisms in the process of evolution should have adapted to radon as a constantly operating environmental factor. Alas, everything is not so simple...

Historically, the harmful effects of natural air radioactivity on the human body were noticed back in the 16th century, when the mysterious “mountain sickness” of miners attracted the attention of doctors: mortality from lung diseases among miners in some mines in the Czech Republic and Germany was 50 times higher than among the rest of the population. The reason for this was explained in our time - there was a high concentration of radon in the air of these mines.
Speculation about the possibility of radiologically harmful effects of radon on the population arose in the late 1960s, when American experts discovered that the concentration of radon in the air of residential buildings, especially one-story buildings, often exceeded levels considered dangerous even for mines. Until 1980, no country in the world established standards for indoor radon levels, and only in recent decades have standards been introduced for existing and planned buildings, recommended by the International Commission on Radiological Protection. NATO even created a special committee on this problem, and in the United States the National Radon Anti-Radon Program still operates (and is well funded).

So, radon - how to detect it, assess the reality of the danger and protect against this threat? For this purpose - the simplest, at the everyday level, information.

Radon - what is it?

Radon is a radioactive gas that is ubiquitous in nature. It is almost 7.5 times heavier than air, is highly soluble in water, and has no color, taste or smell.

Where does radon come from?

Radon is formed as a result of the natural radioactive decay of uranium, so radon is found in high concentrations in soil androcks containing radioactive elements. Radon may be releasedalso from soils containing certain types of industrial waste, such aswaste rock from mining and processing enterprises and mines.

In open spaces, radon concentrations are so low that they are not usually a concern. However, radon accumulates inside closed spaces (such as a home). The level of radon in a building is determined by both the composition of building materials and the concentration of radon in the soil under the building. Another source of radon entering residential premises is water and natural gas.

Radon concentration intap water is extremely small. However, water from some sources, especially from deep wells or artesian wells, contains a lot of radon - up to 1400 kBq/m 3, or 3,000,000 times more than in lake or river water. Radon enters natural gas underground. During processing and storage of gas before it reaches the consumer, most of the radon evaporates, but the concentration of radon in the room can increase noticeably if stoves, heating and other heating devices in which gas is burned are not equipped with an exhaust hood.

How does radon affect health?

The main health impact of radon is an increased risk of lung and upper stomach cancer. Of course, not every excess level leads to the development of cancer, but evidence shows that the risk of cancer from radon exposure depends on its (radon) concentration.

How does radon lead to cancer?

Radon itself decays naturally and forms radioactive decay products. When radon and its decay products are inhaled into the lungs and when it enters the esophagus and stomach with saliva, the decay process continues. This leads to small bursts of released energy already inside the tissues and the occurrence of microburns. In addition, the cells of internal organs are “bombarded” with α- and β-particles. In this case, tissues and cells can be destroyed, contributing to the appearance of cancer.

How does radon enter homes?

Radon is a gas that can seep through voids in the soil and materials that make up your home. Radon can seep through dirt floors, cracks in concrete floors and walls, floor drains, gutters, joints, cracks or pores in hollow block walls.Radon is highly soluble in water, so it is found in all natural waters, and in deep groundwater there is, as a rule, noticeably more of it than in surface drains and reservoirs. For example, in groundwater its concentration can be a million times higher than in lakes and rivers.

Radon enters the room atmosphere from water, released from air bubbles contained in the water. This occurs most intensely when water splashes, evaporates or boils (for example, in a shower or steam room). When using large public water storage tanks, radon usually does not cause harm, because evaporates before the water reaches the house.

Radon is released from building materials if materials with a relatively high content of radium (uranium, thorium) were used, while low radioactivity for other types of radiation does not guarantee safety for radon.

However, the main, most likely way of radon accumulation in premises is associated with the release of radon directly from the soil on which the building is built.

In the practice of geological research, there are often cases when weakly radioactive rocks contain radon in their voids and cracks in quantities hundreds and thousands of times greater than more radioactive rocks. With seasonal fluctuations in temperature and air pressure, radon is released into the atmosphere. The construction of buildings and structures directly above such cracked zones results in a continuous flow of ground air containing high concentrations of radon entering these structures from the bowels of the Earth, which, accumulating in the indoor air, creates a serious radiological hazard for the people in them.

The level of radon concentration in the atmosphere of houses significantly depends on the natural and artificial ventilation of the room, the thoroughness of the sealing of windows, wall joints and vertical communication channels, the frequency of room ventilation, etc. For example, the highest concentrations of radon in residential buildings are observed during the cold season, when measures are traditionally taken to insulate premises and reduce air exchange with the environment. However, properly executed supply and exhaust ventilation gives the best results in reducing radon risk in existing buildings. An analysis of radon activity shows that even a single air exchange per hour reduces the radon concentration by almost a hundred times.

Do I need to have my home inspected? Yes.

In accordance with Article 15 of the Federal Law “On Radiation Safety of the Population”, all buildings and structures put into operation are subject to mandatory radiation monitoring. But “it was smooth on paper, but they forgot about the ravines...”. One gets the impression that many of the leaders on whom the implementation of this law depends either simply do not know about its existence, or act under the already familiar motto “What do we have here, Chernobyl, or what?” And for some reason, the obligation of construction organizations to submit documents confirming the radiation safety of buildings put into operation was removed from the new Town Planning Code. And the Code has greater legal force than a separate Law. Those. the implementation of the long-suffering Law “On Radiation Safety of the Population” is left to the discretion of local Administrations with all the ensuing consequences... By the way, in the capital of the Krasnodar Territory this Law is strictly implemented. And according to colleagues, in the resort city of Anapa, the implementation of this Law is supervised by the prosecutor’s office...

The problem is also that it is necessary to conduct an individual inspection of each house and, if necessary, choose a method of protection from radon (ensuring sufficient air exchange, concreting basements, covering the surfaces of building structures with a sealing compound, etc.). And this is easier and cheaper to do not when people have moved into the house, but at the stage of its preliminary readiness for commissioning. From my own experience, I know that even simple treatment of cracks in the interfloor ceiling between the basement and the first floor in one building I examined reduced the concentration of radon in residential premises to almost zero.

However, if you suspect increased levels of radon in your home, then you should decide to have an inspection carried out by competent organizations that have the appropriate equipment, accreditation certificate and experience in this field.

And, in conclusion, some simple tips on how to use simple methods to reduce the harm from exposure to radon (if any).

Stop smoking in the home - smoking increases exposure to radon, and radon-related lung cancer is three times higher among smokers than non-smokers.

Spend less time in areas of the home with high radon concentrations, such as the basement.
Open windows and turn on fans more often to allow more outside air into your home. This is especially important for basements.

If there is a ventilated space in your house between the floor of the first floor and the ground, keep the air dampers open on all sides of the house at all times.

I really hope that this article was interesting and, perhaps, useful to you. Be healthy.

In light of the rapid development of science and technology, experts express concern about the lack of promotion of radiation hygiene among the population. Experts predict that in the next decade, “radiological ignorance” could become a real threat to the safety of society and the planet.

The Invisible Killer

In the 15th century, European doctors were baffled by the abnormally high mortality rate from pulmonary diseases among workers in mines extracting iron, base metals and silver. A mysterious illness called “mountain sickness” affected miners fifty times more often than the average person. Only at the beginning of the 20th century, after the discovery of radon, was it recognized as the cause of stimulating the development of lung cancer among miners in Germany and the Czech Republic.

What is radon? Does it only have a negative effect on the human body? To answer these questions, we should recall the history of the discovery and study of this mysterious element.

Emanation means "flowing out"

The English physicist E. Rutherford is considered to be the discoverer of radon. It was he who noticed in 1899 that thorium-based preparations, in addition to heavy α-particles, emit a colorless gas, leading to an increase in the level of radioactivity in the environment. The researcher called the supposed substance an emanation of thorium (from emanation (Latin) - outflow) and assigned it the letter designation Em. Similar emanations are also inherent in radium preparations. In the first case, the emitted gas was called thoron, in the second - radon.

Later it was possible to prove that the gases are radionuclides of the new element. It was first isolated in its pure form by the Scottish chemist, Nobel laureate (1904) William Ramsay (together with Whitlow Gray) in 1908. Five years later, the element was finally assigned the name radon and the symbolic designation Rn.

In the chemical elements of D.I. Mendeleev, radon is in the 18th group. Has atomic number z=86.

All existing isotopes of radon (more than 35, with mass numbers from 195 to 230) are radioactive and pose a certain danger to humans. There are four types of atoms of an element found in nature. All of them are part of the natural radioactive series of actinouranium, thorium and uranium - radium. Some isotopes have their own names and, according to historical tradition, are called emanations:

sea anemone - actinone 219 Rn;
thorium - thoron 220 Rn;
radium - radon 222 Rn.

The latter is the most stable. radon 222 Rn - 91.2 hours (3.82 days). The steady state time of the remaining isotopes is calculated in seconds and milliseconds. When alpha particles decay with radiation, polonium isotopes are formed. By the way, it was during the study of radon that scientists first encountered numerous varieties of atoms of the same element, which were later called isotopes (from the Greek “equal”, “same”).

Physical and chemical properties

Under normal conditions, radon is a colorless and odorless gas, the presence of which can only be determined with special instruments. Density - 9.81 g/l. It is the heaviest (air is 7.5 times lighter), the rarest and most expensive of all gases known on our planet.

It is highly soluble in water (460 ml/l), but the solubility of radon in organic compounds is an order of magnitude higher. It has a fluorescence effect caused by its own high radioactivity. The gaseous and liquid state (at temperatures below -62˚С) is characterized by a blue glow, while the crystalline state (below -71˚С) is yellow or orange-red.

The chemical characteristics of radon are determined by its belonging to the group of inert (“noble”) gases. It is characterized by chemical reactions with oxygen, fluorine and some other halogens.

On the other hand, the unstable nucleus of an element is a source of high-energy particles that affect many substances. Exposure to radon causes staining of glass and porcelain, decomposes water into oxygen, hydrogen and ozone, destroys paraffin and petroleum jelly, etc.

Getting radon

To isolate radon isotopes, it is enough to pass a stream of air over a substance containing radium in one form or another. The gas concentration in the stream will depend on many physical factors (humidity, temperature), on the crystal structure of the substance, its composition, porosity, homogeneity and can range from small fractions to 100%. Usually solutions of radium bromide or radium chloride in hydrochloric acid are used. Solid porous substances are used much less frequently, although radon is released more pure.

The resulting gas mixture is purified from water vapor, oxygen and hydrogen by passing it through a hot copper mesh. The remainder (1/25,000 of the original volume) is condensed and impurities of nitrogen, helium and inert gases are removed from the condensate.

For note: throughout the world, only a few tens of cubic centimeters of the chemical element radon are produced per year.

Distribution in nature

Radium nuclei, the fission product of which is radon, are in turn formed during the decay of uranium. Thus, the main source of radon is soils and minerals containing uranium and thorium. The highest concentrations of these elements are in igneous, sedimentary, metamorphic rocks, and dark-colored shales. Radon gas, due to its inertness, easily leaves the crystal lattices of minerals and easily spreads over long distances through voids and cracks in the earth's crust, releasing into the atmosphere.

In addition, interstratal groundwater, washing such rocks, is easily saturated with radon. Radon water and its certain properties were used by man long before the discovery of the element itself.

Friend or foe?

Despite thousands of scientific and popular science articles written about this radioactive gas, there is no clear answer to the question: “What is radon and what is its significance for humanity?” seems difficult. Modern researchers face at least two problems. The first is that in the sphere of influence of radon radiation on living matter, it is both a harmful and beneficial element. The second is the lack of reliable means of registration and monitoring. The existing radon detectors in the atmosphere, even the most modern and sensitive ones, when repeated measurements can produce results that differ several times.

Beware of radon!

A person receives the main dose of radiation (more than 70%) in the process of life thanks to natural radionuclides, among which the leading position belongs to the colorless gas radon. Depending on the geographical location of the residential building, its “contribution” can range from 30 to 60%. A constant amount of unstable isotopes of a dangerous element in the atmosphere is maintained by a continuous supply from earth rocks. Radon has the unpleasant property of accumulating inside residential and public buildings, where its concentration can increase tens or hundreds of times. The danger to human health is not so much the radioactive gas itself, but rather the chemically active isotopes of polonium 214 Po and 218 Po, formed as a result of its decay. They are firmly retained in the body, having a detrimental effect on living tissue by internal α-radiation.

In addition to asthmatic attacks of suffocation and depression, dizziness and migraines, this is fraught with the development of lung cancer. The risk group includes workers of uranium mines and mining and processing plants, volcanologists, radon therapists, the population of unfavorable areas with a high content of radon derivatives in the earth's crust and artesian waters, and radon resorts. To identify such areas, radon hazard maps are compiled using geological and radiation-hygienic methods.

For a note: it is believed that it was exposure to radon that provoked the death of the Scottish researcher of this element, William Ramsay, from lung cancer in 1916.

Methods of protection

In the last decade, following the example of its Western neighbors, the necessary anti-radon measures began to spread in the countries of the former CIS. Regulatory documents have appeared (SanPin 2.6.1., SP 2.6.1.) with clear requirements to ensure radiation safety of the population.

The main measures to protect against soil gases and natural sources of radiation include:

Arrangement of a monolithic concrete slab with a crushed stone base and reliable waterproofing on an earthen underground wooden floor.
Providing enhanced ventilation of basement and basement spaces, ventilation of residential buildings.
Water entering kitchens and bathrooms must undergo special filtration, and the premises themselves must be equipped with forced exhaust devices.

Radiomedicine

Our ancestors did not know what radon was, but even the glorious horsemen of Genghis Khan healed their wounds with the waters of the Belokurikha (Altai) springs, saturated with this gas. The fact is that in microdoses radon has a positive effect on vital human organs and the central nervous system. Exposure to radon waters accelerates metabolic processes, due to which damaged tissues are restored much faster, the functioning of the heart and circulatory system is normalized, and the walls of blood vessels are strengthened.

Resorts in the mountainous regions of the Caucasus (Essentuki, Pyatigorsk, Kislovodsk), Austria (Gastein), Czech Republic (Jachimov, Karlovy Vary), Germany (Baden-Baden), Japan (Misasa) have long enjoyed well-deserved fame and popularity. Modern medicine, in addition to radon baths, offers treatment in the form of irrigation and inhalation under the strict supervision of an appropriate specialist.

In the service of humanity

The scope of radon gas is not limited to medicine. The adsorption ability of element isotopes is actively used in materials science to measure the degree of heterogeneity of metal surfaces and decoration. In steel and glass production, radon is used to control the progress of technological processes. It is used to test gas masks and chemical protective equipment for leaks.

In geophysics and geology, many methods for searching and detecting deposits of minerals and radioactive ores are based on the use of radon surveys. The concentration of radon isotopes in the soil can be used to judge the gas permeability and density of rock formations. Monitoring the radon situation looks promising in terms of predicting upcoming earthquakes.

We can only hope that humanity can still cope with the negative effects of radon and that the radioactive element will only bring benefits to the planet’s population.

The International Commission on Radiological Protection's "Official Report on Radon" states that the annual effective individual radiation dose from radon should not exceed 10 mSv/year. According to the Russian Federal Service for Surveillance in the Sphere of Consumer Rights Protection and Human Welfare, in 2010, critical groups of the population were identified, the radiation doses of which significantly exceed the average for the Russian Federation. Such population groups were identified in the Republic of Tyva, in the Altai Territory, in the Voronezh and Kemerovo regions. The reason for increased exposure is the high content of radon isotopes in the air of residential premises. In temperate climates, radon concentrations in indoor spaces are on average approximately 8 times higher than in outdoor air. The highest values of average annual effective doses of irradiation of the population from natural sources of ionizing radiation according to research data from 2001-2010. registered in the Altai Republic (9.54 mSv/year) and the Jewish Autonomous Okrug (7.20 mSv/year), the average annual doses of natural radiation to residents of the Republic of Tyva, Irkutsk region, Stavropol and Trans-Baikal territories exceed 5 mSv/year. High rates of annual effective doses of radiation to the population are also observed in the republics of Buryatia, Ingushetia, Kalmykia, North Ossetia, Tyva, in the Kabardino-Balkarian and Karachay-Cherkess Republics, in the Stavropol Territory, in Ivanovo, Irkutsk, Kaluga, Kemerovo, Lipetsk, Novosibirsk, Rostov , Sverdlovsk. See the table with the average annual effective radiation doses of the Russian population according to the Federal Service for Surveillance on Consumer Rights Protection and Human Welfare.

The average individual annual effective radiation dose per resident of the Russian Federation, estimated based on data for the entire observation period from 2001 to 2010, is 3.38 mSv/year. The contribution of the internal exposure dose to the population due to inhalation of radon isotopes (222 Rn and 220 Rn) and their short-lived daughter decay products is 1.98 mSv/year or about 59% of the total dose due to all natural radiation sources. In this case, the contribution of external radiation is about 19% of the total dose, cosmic radiation - slightly less than 12%, the contribution of 40K, widespread in nature, is 5%, and the radiation dose due to the content of natural and man-made (137 Cs and 90 Sr) radionuclides in food - about 4%. The average dose due to consumption of drinking water is less than 1% of the total radiation dose, and due to inhalation of long-lived natural radionuclides with atmospheric air - less than 0.2% of the total dose. About 90% of the inhalation radiation dose is caused by inhalation of daughter products of radon isotopes in indoor and atmospheric air. At the same time, radon is the only natural source of radiation that can be regulated at an economically justifiable cost.
Although in 1994, by Decree of the Government of the Russian Federation No. 809 dated July 6, 1994, the Federal Target Program “Reducing the level of exposure of the population of Russia and production personnel from natural radioactive sources” was adopted, in the domestic popular construction literature the dangers associated with the constant penetration of radon into residential premises , most often pass by in silence. To understand the relevance of the radon problem, read. Modern studies have shown that radon is a cause of central lung cancer, and the risk of the disease increases with increasing indoor radon concentrations and long-term residence in radon-prone areas. However, despite the numerous ways radon enters a house, it is possible to protect it from increased radon concentrations using simple and inexpensive technical solutions for protecting a low-rise building from radon.

Alberg AJ., Samet JM. Epidemiology of Lung Cancer. Chest. 2003; 123:21-49
U.S. National Institutes of Health. National Cancer Institute. Factsheet; Radon and Cancer: Questions and Answers. July 13, 2004. Accessed on November 17, 2009
Steindorf K., Lubin J., Wichmann H.E., Becher H. Lung Cancer Deaths Attributable to Indoor Radon Exposure in West Germany. //Intern. J. Epidemiol. 1995. V. 24. No. 3. P. 485-492.
Tikhonov M.N. Radon: sources, doses and unresolved issues // Atomic strategy. -2006.- No. 23, July
Radiation doses to the population of the Russian Federation in 2010. - St. Petersburg: St. Petersburg Research Institute of Radiation Hygiene named after Professor P.V. Ramzaeva, 2011. - P. 17.
Radiation doses to the population of the Russian Federation in 2010. - St. Petersburg: St. Petersburg Research Institute of Radiation Hygiene named after Professor P.V. Ramzaeva, 2011. - P.18
Krisyuk E.M. Levels and consequences of public exposure // ANRI. - 2002. - N 1(28). - P.4-12.

Literature

INTRODUCTION

Everywhere and everywhere we are surrounded by atmospheric air. What does it consist of? The answer is not difficult: out of 78.08 percent nitrogen, 20.9 percent oxygen, 0.03 percent carbon dioxide, 0.00005 percent hydrogen, about 0.94 percent is the share of so-called inert gases. The latter were discovered only at the end of the last century. Radon is formed during the radioactive decay of radium and is found in negligible quantities in uranium-containing materials, as well as in some natural waters.

Relevance of the research. According to the International Commission on Radiological Protection (ICRP), the UN Scientific Committee on the Effects of Atomic Radiation (SCEAR), the largest part of the radiation dose (about 80% of the total) received by the population under normal conditions is associated precisely with natural sources of radiation. More than half of this dose is due to the presence of radon gas and its daughter decay products (DDP) in the air of buildings in which people spend more than 70% of their time.

Radon, a noble inert gas, is becoming increasingly important in human life. Unfortunately, it is predominantly negative - radon is radioactive and therefore dangerous. And since it is continuously released from the soil, it is distributed throughout the earth’s crust, in underground and surface water, in the atmosphere, and is present in every home.

Civilized society has already realized that the radon danger is a large and complex complex problem, since the radioecological processes caused by radon occur at three structural levels of matter: nuclear, atomic-molecular and macroscopic. Therefore, its solution is divided into diagnostic tasks and technologies for subsequent neutralization of the effects of radon on humans and biological objects.

Currently, after the long-term refusal of the leading world powers to test nuclear weapons, the risk of receiving a significant dose of radiation in the minds of most people is associated with the action of nuclear power plants. Especially after the Chernobyl disaster. However, you should know that there is a risk of exposure even if you are in your own home. The threat here is posed by natural gas - radon and heavy metal products of its decay. Humanity has experienced their effects throughout its entire existence.

Purpose of the work: Study the nature of radon, its compounds, impact on humans, as well as study the sources of radon entry into the building and evaluate the effectiveness of using various materials as radon-protective coatings.

GENERAL INFORMATION ABOUT RADON

Already from the 16th century, people knew about the disastrous consequences of staying in certain areas and zones, but no one had any idea about the gas itself. In the mining villages in the mountains of southern Germany, women walked down the aisle several times: their husbands were carried away by a mysterious, fast-moving disease - “miner's consumption”. Doctors who practiced in those places mentioned the existence of pits in which, in the absence of proper ventilation, people experienced shortness of breath and increased heart rate, often lost consciousness and sometimes died. At the same time, no impurities were detected in the air either by taste or smell. Therefore, it is not surprising that they believed that people were being destroyed by disturbed mountain spirits. And only the great Paracelsus, who worked as a doctor in the same area, wrote about the need to purify the air in mines: “We are obliged to prevent the body from coming into contact with the emanations of metals, for if the body is damaged by them once, there can be no cure.”

The “miner’s consumption” was finally dealt with only in 1937, having established that this disease is nothing more than a form of lung cancer caused by high concentrations of radon.

The radon problem has been studied since the earliest stages of the development of nuclear physics, but it began to emerge especially seriously and on a large scale after the moratorium on nuclear explosions and thanks to the declassification of test sites. When comparing the effects of radiation, it turned out that each apartment, each room has its own local nuclear radon “test sites”.

Radon isotopes are sorbed (absorbed) by solids. Coal is the most productive in this regard, so coal mines should be under increased government attention. The same applies to all industries that consume this type of fuel.

Sorbed radon atoms are very mobile and move from the surface of the solid into the deep layers. This applies to organic and inorganic colloids, biological tissues, which significantly increases the radon hazard. The sorbing properties of substances significantly depend on the temperature of previously adsorbed components, moisture saturation and many other parameters. It is desirable to involve these properties in the development of various anti-radon agents.

At the Kazakh National University named after. Al-Farabi measured the altitude profiles of radon distribution on the floors of buildings, indoors and outdoors. Well-known patterns have been confirmed, but others have also been found that are used experimentally for the development of anti-radon technical means. It has been established that several times a month the radon content in the ground atmosphere can increase many times. These “radon storms” are accompanied by a sharp increase in radioactivity in the air, not only contributing to the development of lung cancer, but also causing functional impairment in practically healthy people - about 30% experience shortness of breath, rapid heartbeat, migraine attacks, insomnia, etc. Disturbances pose a particular danger to sick and elderly people, as well as children.

It turned out that the occurrence of radon-aeroion storms is associated with physical processes occurring on the Sun, with the appearance of dark spots on the surface of the star. An interesting suggestion about a possible mechanism linking solar activity with a significant increase in radon content was made by Moscow scientist A.E. Shemyi-Zadeh. Having analyzed data on atmospheric radon activity obtained in Central Asia, the Baltic States, Sweden, etc., he revealed a correlation between the level of radon activity in the earth’s atmosphere and solar and geomagnetic processes in different years and in different regions.

The concentration of radon in micropores of rocks (common granites and basalts) is millions of times higher than in the surface atmosphere and reaches 0.5-5.0 Bq/m3. Radon activity is usually measured in the number of its decays in 1 m3 - 1 Becquerel (Bq) corresponds to one decay per second. This radon, as the scientist’s calculations showed, is “squeezed out” of micropores emerging on the surface due to magnetostrictive compression-tension in the high-frequency field of geomagnetic disturbances. The amplitude of magnetostriction occurring in a constant magnetic field of the Earth under the influence of small geomagnetic disturbances is proportional to the magnetite content in the rock (usually up to 4%), and the frequency is determined by geomagnetic variations. The amplitude of magnetostrictive compression of rocks in the field of geomagnetic disturbances is very small, but the effect of radon displacement is due, firstly, to the high frequency of disturbances, and secondly, to the high gas concentration. It turns out that if in a column of atmospheric air with a cross-section of one kilometer you “stir” a layer isolated from rocks only one millimeter thick, then the concentration of radon in this column will increase 10 times.

OPENING HISTORY

After the discovery of radium, when scientists were eagerly exploring the secrets of radioactivity, it was found that solid substances that were in close proximity to radium salts became radioactive. However, a few days later the radioactivity of these substances disappeared without a trace.

Radon was discovered several times, and unlike other similar stories, each new discovery did not refute, but only complemented the previous ones. The fact is that none of the scientists dealt with the element radon - an element in our usual understanding of the word. One of the current definitions of an element is “a collection of atoms with a total number of protons in the nucleus,” i.e., the difference can only be in the number of neutrons. Essentially, an element is a collection of isotopes. But in the first years of our century, the proton and neutron had not yet been discovered, and the very concept of isotonia did not exist.

While studying the ionization of air by radioactive substances, the Curies noticed that various bodies located near a radioactive source acquire radioactive properties, which persist for some time after the removal of the radioactive drug. Marie Curie-Skłodowska called this phenomenon induced activity. Other researchers, most notably Rutherford, tried in 1899/1900. explain this phenomenon by the fact that a radioactive body forms some radioactive outflow, or emanation (from the Latin emanare - to flow out and emanatio - outflow), permeating the surrounding bodies. However, as it turned out, this phenomenon is characteristic not only of radium preparations, but also of thorium and actinium preparations, although the period of induced activity in the latter cases is shorter than in the case of radium. It was also discovered that emanation is capable of causing phosphorescence of certain substances, for example, a precipitate of zinc sulfide. Mendeleev described this experiment, demonstrated to him by the Curies, in the spring of 1902.

Soon, Rutherford and Soddy were able to prove that emanation is a gaseous substance that obeys Boyle’s law and when cooled turns into a liquid state, and a study of its chemical properties showed that emanation is an inert gas with an atomic weight of 222 (later established). The name emanation was proposed by Rutherford, who discovered that its formation from radium is accompanied by the release of helium. This name was later changed to "Radium Emanation - Ra Em" in order to distinguish it from the emanations of thorium and actinium, which later turned out to be isotopes of radium emanation. In 1911, Ramsay, who determined the atomic weight of radium emanation, gave it a new name “Niton” from the Latin. nitens (shiny, glowing); With this name, he obviously wanted to emphasize the property of the gas to cause phosphorescence of certain substances. Later, however, the more precise name radon was adopted - a derivative of the word "radium". Emanations of thorium and actinium (radon isotopes) began to be called thoron and actinon.

First of all, in the years since the discovery of radon, its basic constants have hardly been clarified or revised. This is evidence of the high experimental skill of those who first identified them. Only the boiling point (or the transition to a liquid state from a gaseous state) was clarified. In modern reference books it is indicated quite definitely - minus 62° C.

It should also be added that the idea of the absolute chemical inertness of radon, as well as other heavy noble gases, has become a thing of the past. Even before the war, Corresponding Member of the USSR Academy of Sciences B.A. Nikitin at the Leningrad Radium Institute obtained and studied the first complex compounds of radon - with water, phenol and some other substances. Already from the formulas of these compounds: Rn 6H 2 O, Rn 2CH 3 C 6 H 5, Rn 2C 6 H 5 OH - it is clear that these are so-called inclusion compounds, that the radon in them is associated with molecules of water or organic matter only by van forces der Waltz. Later, in the 60s, true radon compounds were obtained. According to the theoretical concepts that had developed by this time about noble gas halides, radon compounds should have sufficient chemical resistance: RnF 2, RnF 4, RnCl 4, RnF 6.

Radon fluorides were obtained immediately after the first xenon fluorides, but they could not be accurately identified. Most likely, the resulting low-volatile substance is a mixture of radon fluorides.

Radon, discovered by Dorn, is the longest-lived isotope of element No. 86. It is formed during the α decay of radium-226. The mass number of this isotope is 222, the half-life is 3.82 days. It exists in nature as one of the intermediate links in the decay chain of uranium-238.

An emanation of thorium (thoron), discovered by Rutherford and Owens, a member of another naturally occurring radioactive family, the thorium family. It is an isotope with a mass number of 220 and a half-life of 54.5 seconds.

Actinon, discovered by Debierne, is also a member of the radioactive thorium family. This is the third natural isotope of radon and the shortest-lived of the natural ones. Its half-life is less than four seconds (more precisely 3.92 seconds), its mass number is 219.

In total, 19 isotopes of radon are now known with mass numbers of 204 and from 206 to 224. 16 isotopes have been obtained artificially. Neutron-deficient isotopes with mass numbers up to 212 are obtained in reactions of deep fission of uranium and thorium nuclei with high-energy protons. These isotopes are needed to obtain and study the artificial element astatine. An effective method for separating neutron-deficient isotopes of radon was recently developed at the Joint Institute for Nuclear Research.

PHYSICAL PROPERTIES OF RADON

Noble gases are colorless monatomic gases without color or odor.
Noble gases have higher electrical conductivity than other gases and glow brightly when current passes through them: helium with a bright yellow light, because in its relatively simple spectrum the double yellow line predominates over all others; neon has a fiery red light, since its brightest lines lie in the red part of the spectrum.
The saturated nature of the atomic molecules of inert gases is also reflected in the fact that inert gases have lower liquefaction and freezing points than other gases with the same molecular weight.

Radon glows in the dark, emits heat without heating, and over time forms new elements: one of them is gaseous, the other is a solid substance. It is 110 times heavier than hydrogen, 55 times heavier than helium, and more than 7 times heavier than air. One liter of this gas weighs almost 10 g (more precisely 9.9 g).

Radon is a colorless gas, chemically completely inert. Radon dissolves in water better than other inert gases (up to 50 volumes of radon dissolve in 100 volumes of water). When cooled to minus 62°C, radon condenses into a liquid that is 7 times heavier than water (the specific gravity of liquid radon is almost equal to the specific gravity of zinc). At minus 71°C, radon “freezes”. The amount of radon emitted by radium salts is very small, and to obtain 1 liter of radon, you need to have more than 500 kg of radium, while in 1950 no more than 700 g of it were obtained throughout the entire globe.

Radon is a radioactive element. Emitting α-rays, it turns into helium and a solid, also radioactive element, which is one of the intermediate products in the chain of radioactive transformations of radium.

It was natural to expect that such chemically inert substances as inert gases should not affect living organisms. But that's not true. Inhalation of higher inert gases (of course, mixed with oxygen) leads a person to a state similar to intoxication with alcohol. The narcotic effect of inert gases is caused by dissolution in nerve tissues. The higher the atomic weight of an inert gas, the greater its solubility and the stronger its narcotic effect.

At the time of the discovery of radon, a typical representative of the noble gases, it was believed that the elements of this group were chemically inert and incapable of forming true chemical compounds. Only clathrates were known, the formation of which occurs due to van der Waals forces. These include hydrates of xenon, krypton and argon, which are obtained by compressing the corresponding gas above water to a pressure exceeding the elasticity of hydrate dissociation at a given temperature. To obtain similar radon clathrates and detect them by changes in vapor pressure, an almost inaccessible amount of this element would be required. A new method for obtaining clathrate compounds of noble gases was proposed by B.A. Nikitin and consisted of isomorphic coprecipitation of a molecular compound of radon with crystals of a specific carrier. Studying the behavior of radon during the processes of coprecipitation with hydrates of sulfur dioxide and hydrogen sulfide, Nikitin showed that there is a radon hydrate that is isomorphically coprecipitated with SO 2Х6 H 2 O and H 2 S Х6 H 2 O. The mass of radon in these experiments was 10-11 g Similarly, clathrate compounds of radon with a number of organic compounds, for example, with toluene and phenol, were obtained.

Studies of the chemistry of radon are possible only with submicroquantities of this element when using xenon compounds as specific carriers. It should, however, be taken into account that between xenon and radon there are 32 elements (along with the 5d-, 6s- and 6p-orbits the 4f-orbits are filled), which determines the greater metallicity of radon compared to xenon.

The first true radon compound, radon difluoride, was obtained in 1962, shortly after the synthesis of the first xenon fluorides. RnF 2 is formed both during the direct interaction of radon and fluorine gases at 400°C, and during its oxidation with krypton difluoride, xenon di- and tetrafluorides and some other oxidizing agents. Radon difluoride is stable up to 200°C and is reduced to elemental radon by hydrogen at 500°C and an H2 pressure of 20 MPa. Radon difluoride was identified by studying its cocrystallization with fluorides and other xenon derivatives.

No radon compound has been obtained with any oxidizing agent, where its oxidation state would be higher than +2. The reason for this is the greater stability of the fluorination intermediate product (RnF+X-) compared to a similar form of xenon. This is due to the higher ionicity of the bond in the case of a radon-containing particle. As further studies have shown, the kinetic barrier to the formation of higher radon fluorides can be overcome either by introducing nickel difluoride, which has the highest catalytic activity in xenon fluoridation processes, into the reaction system, or by carrying out the fluorination reaction in the presence of sodium bromide. In the latter case, the fluoride donor ability of sodium fluoride, greater than that of radon difluoride, allows the conversion of RnF+ into RnF 2 as a result of the reaction: RnF+SbF 6 + NaF = RnF2 + Na+SbF 6 . RnF 2 is fluorinated to form higher fluorides, the hydrolysis of which produces higher radon oxides. Confirmation of the formation of radon compounds in higher valence states is the effective cocrystallization of barium xenates and radonates.

For a long time, conditions were not found under which noble gases could enter into chemical interactions. They did not form true chemical compounds. In other words, their valency was zero. On this basis, it was decided to consider the new group of chemical elements zero. The low chemical activity of noble gases is explained by the rigid eight-electron configuration of the outer electron layer. The polarizability of atoms increases with increasing number of electronic layers. Therefore, it should increase when going from helium to radon. The reactivity of noble gases should also increase in the same direction.
Thus, already in 1924, the idea was expressed that some compounds of heavy inert gases (in particular, xenon fluorides and chlorides) are thermodynamically quite stable and can exist under normal conditions. Nine years later, this idea was supported and developed by famous theorists - Pauling and Oddo. The study of the electronic structure of the shells of krypton and xenon from the standpoint of quantum mechanics led to the conclusion that these gases are able to form stable compounds with fluorine. There were also experimenters who decided to test the hypothesis, but time passed, experiments were carried out, and xenon fluoride was not obtained. As a result, almost all work in this area was stopped, and the opinion about the absolute inertness of noble gases was finally established.

Historically, the first and most widespread is the radiometric method for determining radon by the radioactivity of its decay products and comparing it with the activity of a standard.

The 222Rn isotope can also be determined directly from the intensity of its own α-radiation. A convenient method for determining radon in water is to extract it with toluene and then measure the activity of the toluene solution using a liquid scintillation counter.

When radon concentrations in the air are significantly lower than the maximum permissible limits, it is advisable to determine it after preliminary concentration by chemical binding with suitable oxidizing agents, for example BrF 2 SbF 6, O 2 SbF 6, etc.

RECEIVING

To obtain radon, air is blown through an aqueous solution of any radium salt, which carries with it the radon formed during the radioactive decay of radium. Next, the air is carefully filtered to separate microdroplets of the solution containing the radium salt, which can be captured by the air current. To obtain radon itself, chemically active substances (oxygen, hydrogen, water vapor, etc.) are removed from a mixture of gases, the residue is condensed with liquid nitrogen, then nitrogen and other inert gases (argon, neon, etc.) are distilled from the condensate.

As stated earlier, the source of the natural isotope 222Rn is 226Ra. In equilibrium with 1 g of radium there is 0.6 μl of radon. Attempts to isolate radon from inorganic radium salts have shown that even at temperatures close to the melting point, radon is not completely extracted from them. Salts of organic acids (palmitic, stearic, caproic), as well as hydroxides of heavy metals, have a high emanating ability. To prepare a highly emanating source, the radium compound is usually coprecipitated with barium salts of the indicated organic acids or hydroxides of iron and thorium. The isolation of radon from aqueous solutions of radium salts is also effective. Typically, radium solutions are left for some time in the ampoule to accumulate radon; Radon is pumped out at certain intervals. The release of radon after purification is usually carried out by physical methods, for example, adsorption with activated carbon followed by desorption at 350°C.

In addition to physical methods of capturing radon (adsorption, cryogenic, etc.), effective separation of radon from a gas mixture can be achieved by converting it into a non-volatile chemical form under the influence of oxidizers. Thus, radon can be practically quantitatively absorbed by salts of the composition ClF 2 SbF 6, BrF 2 SbF 6, O 2 SbF 6 and some liquid fluorohalides as a result of the formation of non-volatile salts of the composition RnF + X-, where X- is a complex anion.

The release of artificially produced radon isotopes, mainly 211Rn (T = 14 h), is associated with its separation from the target material - thorium and a complex mixture of products of deep elimination reactions.

BEING IN NATURE

Radon is found in negligible quantities in a dissolved state in the waters of mineral springs, lakes and medicinal mud. It is in the air that fills caves, grottoes, and deep narrow valleys. In atmospheric air, the amount of radon is measured in values of the order of 5·10-18% - 5·10-21% by volume.

It is part of the radioactive series 238 U, 235 U and 232 Th. Radon nuclei constantly arise in nature during the radioactive decay of parent nuclei. The equilibrium content in the earth's crust is 7·10−16% by mass. Due to its chemical inertness, radon relatively easily leaves the crystal lattice of the “parent” mineral and enters groundwater, natural gases and air. Since the longest-lived of the four natural isotopes of radon is 222 Rn, it is its content in these environments that is maximum.

The concentration of radon in the air depends primarily on the geological situation (for example, granites, which contain a lot of uranium, are active sources of radon, while at the same time there is little radon above the surface of the seas), as well as on the weather (during rain, microcracks through which radon comes from the soil, are filled with water; snow cover also prevents radon from entering the air).

APPLICATION OF RADON

In fairness, one cannot fail to note some of the healing properties of radon associated with the use of so-called radon baths. They prove useful in the treatment of a number of chronic diseases: duodenal and gastric ulcers, rheumatism, osteochondrosis, bronchial asthma, eczema, etc. Radon therapy can replace poorly tolerated medications. Unlike hydrogen sulfide, carbon dioxide, and mud baths, radon baths are much easier to tolerate. But such procedures must be carried out under the strict supervision of specialists, since therapeutic doses of gas in radon baths are significantly lower than the maximum permissible standards. In this case, the benefits and harms of radon compete with each other. Thus, experts have calculated that the negative effect of taking a session of 15 radon baths of 15 minutes each is equivalent to smoking 6 cigarettes (it is believed that one cigarette can shorten your life by 15 minutes). Therefore, possible harm from radon baths is considered insignificant in the treatment of diseases.

When determining the dose of radiation harmful to human health, there are two concepts. The first is based on the idea that there is a certain threshold dose, below which radiation is not only harmless, but even beneficial for the body. This theory apparently arose by analogy with the idea of small doses of poisons helping to treat a number of diseases, or small doses of alcohol improving a person’s well-being. However, if small doses of poisons or alcohol simply activate individual cells of the body, then even small doses of radiation simply destroy them. Therefore, the authors adhere to a different, non-threshold concept. According to it, the probability of developing cancer is directly proportional to the dose of radiation received during one's lifetime. This means there is no minimum dose below which radiation would be harmless.

Radon is used in agriculture to activate feed for domestic animals, in metallurgy as an indicator in determining the speed of gas flows in blast furnaces and gas pipelines. In geology, measuring the radon content in air and water is used to search for deposits of uranium and thorium, in hydrology - to study the interaction of groundwater and river waters.

Radon is widely used for studying solid-phase transformations. The basis of these studies is the emanation method, which makes it possible to study the dependence of the rate of radon release on the physical and chemical transformations that occur when heating solids containing radium.

Radon is also used in the study of diffusion and transfer phenomena in solids, in the study of movement speed and in the detection of gas leaks in pipelines.

All over the world, enormous efforts are being made to solve the problem of earthquake forecasting, but nevertheless, we often find ourselves powerless in the face of the unexpected onslaught of the elements of the earth's interior. Therefore, the search for new harbingers of seismic events does not stop. Research in recent years has led to the idea of predicting seismic events based on studying the process of radon gas release (exhalation) from rock masses. Analysis of these data takes us back to the old Gilbert-Reid theory of elastic recoil (1911), according to which the accumulation of energy in a rock mass before an earthquake and the release of this energy during an earthquake occur in areas where these rocks experience elastic deformation.

The method of predicting earthquakes, which consists in conducting routine observations of changes in radon concentration in a rock mass, differs in that special observation wells are drilled, the depth of which is less than the depth of the groundwater level, and in each of these wells the dynamics of radon release from the rock mass are continuously recorded and the total amount of seismic energy received in each observation well. And based on a series of observations over time, zones with a consistent decrease or increase in radon emission are identified, taking into account the incoming seismic energy, these zones are plotted on a map of the study area, and based on the area of the zone of dynamic decrease in radon emission, the position of the epicenter and the magnitude of the expected earthquake are judged, and based on the dynamics of the decrease and /or an increase in radon emission in observation wells, the time of the expected seismic event is judged.

RADON IN THE URAL REGION

Almost the highest air pollution in Russia is connected not only with the fact that the largest industrial enterprises of the country have been concentrated in the Urals since the time of the Demidov factory owners. The soil and old Ural Mountains are rife with faults that emit radon that penetrates our homes. In terms of the number of points where this happens, the Sverdlovsk region is in second place in the country.

But when did they start talking so loudly about the radon problem in our Urals? In the late 80s, when the first methodological document on radon control in homes appeared. Then the Yekaterinburg City Hall issued a decree that radon measurements must be carried out in all rental housing. And in 1994, the Federal Target Program “Radon” began to be implemented. It also had a regional part, which, in particular, concerned the Sverdlovsk region.

Previously, its financing, in particular from the Environmental Fund, was more active, and there were more qualitative measurements. The Institute of Industrial Ecology of the Ural Branch of the Russian Academy of Sciences participated in this program and carried out several hundred measurements per year. As a result, there are now materials on measurements in more than three thousand homes in the Sverdlovsk region.

Against the background of the map of the Ural region, a sufficient number of settlements are located in places with a relatively high level of radon hazard. Roughly speaking, the territories of the Sverdlovsk region were divided into 2 parts. In the first, the level of radon danger is relatively higher than in the second, and in the other it is relatively lower than in the first. You can only trust real measurements.

According to data obtained by the Institute of Industrial Ecology of the Ural Branch of the Russian Academy of Sciences, 50 thousand people are exposed to high levels of radon radiation.

In 1.1 percent of dwellings in the Sverdlovsk region, the volumetric activity of radon exceeds the hygienic standard for existing buildings. One percent corresponds to approximately 20 thousand dwellings in the Sverdlovsk region.

WAYS TO SOLUTION THE RADON PROBLEM

Currently, the problem of human exposure to radioactive gas radon remains relevant. Back in the 16th century, there was a high mortality rate among miners in the Czech Republic and Germany. In the 50s of the twentieth century, explanations for this fact appeared. The radioactive gas radon, present in uranium mines, has been proven to have a detrimental effect on the human body. It is interesting to see how attitudes towards the problem of the influence of radon have changed these days.

An analysis of popular scientific publications shows the share of internal exposure from various radiation sources.

Table 1

It follows from the table that 66% of internal exposure is determined by terrestrial radionuclides. According to scientists, radon and its daughter decay products provide approximately ¾ of the annual effective radiation dose that the population receives from terrestrial radiation sources.

According to scientists, radon-222, in terms of its contribution to the total radiation dose, is 20 times more powerful than other isotopes. This isotope is studied more than others and is simply called radon. The main sources of radon are soil and building materials.

All building materials, soil, and the earth's crust contain radionuclides of radium - 226 and thorium - 232. As a result of the decay of these isotopes, radioactive gas - radon - appears. In addition, during α - decays, nuclei are formed that are in an excited state, which, upon transitioning to the ground state, emit γ - quanta. These γ quanta form the radioactive background of the rooms in which we are located. An interesting fact is that radon, being an inert gas, does not form aerosols, i.e. does not attach to dust particles, heavy ions, etc. Due to its chemical inertness and long half-life, radon-222 can migrate through cracks, pores of soil and rock over long distances, and for a long time (about 10 days).

For a long time, the question of the biological influence of radon remained open. It turned out that during decay, all three isotopes of radon form daughter decay products (DPR). They are chemically active. Most of the DPR, by adding electrons, become ions and easily attach to air aerosols, becoming its component. The principle of registering radon in the air is based on the registration of DPR ions. When radon gases enter the respiratory tract, they cause radiation damage to the lungs and bronchi.

How does radon appear in the air? After analyzing the data, the following sources of atmospheric radon can be identified:

table 2

Radon is released from soil and water everywhere, but its concentration in the outside air varies in different parts of the globe. The average level of radon concentration in the air is approximately 2 Bq/m3.

It turned out that a person receives the bulk of the dose caused by radon while being in a closed, unventilated room. In temperate climates, radon concentrations indoors are approximately 8 times higher than in outdoor air. Therefore, we were interested to find out what is the main source of radon in the house. The analysis of print data is given in the table:

Table 3

From the data presented it follows that the volumetric activity of radon in indoor air is formed mainly from the soil. The concentration of radon in the soil is determined by the content of radionuclides radium-226, thorium-228, soil structure and humidity. The structure and structure of the earth's crust determines the diffusion processes of radon atoms and their migration ability. The migration of radon atoms increases with increasing soil moisture. The emission of radon from soil is seasonal.

An increase in temperature causes the pores in the soil to expand, and therefore increases the release of radon. In addition, an increase in temperature increases the evaporation of water, which carries radioactive radon gas into the surrounding space. An increase in atmospheric pressure promotes the penetration of air deeper into the soil, and the concentration of radon decreases. On the contrary, when external pressure decreases, radon-rich ground gas rushes to the surface and the concentration of radon in the atmosphere increases.

An important factor that reduces the entry of radon into a room is the choice of area for construction. In addition to soil and air, building materials are sources of radon in the house. The evaporation of radon from granules of microparticles of rock or building material is called exhalation. Exhalation of radon from building materials depends on their radium content, density, porosity of the material, room parameters, wall thickness, room ventilation. The volumetric activity of radon in indoor air is always higher than in atmospheric air. To characterize building materials, the concept of radon diffusion length in a substance is introduced.

Only those radon atoms that are located in the pores of the material at a depth no greater than the diffusion length come out of the wall. The diagram shows the ways to enter the room:

·Through cracks in monolithic floors;

·Through installation connections;

·Through cracks in the walls;

·At gaps around pipes;

·Through wall cavities.

According to research estimates, the rate of radon entry into a one-story house is 20 Bq/m 3 hour, while the contribution of concrete and other building materials to this dose is only 2 Bq/m 3 hour. The content of radioactive gas radon in indoor air is determined by the content of radium and thorium in building materials. The use of non-waste technologies in the production of building materials affects the volumetric activity of radon indoors. The use of calcium-silicate slag obtained from the processing of phosphate ores, waste rocks from the dumps of processing factories, reduces environmental pollution, reduces the cost of production of building materials, and reduces the cost of radon in humans. Blocks of phosphogins and alum clayey shales have particularly high specific activity. Since 1980, the production of such aerated concrete has been discontinued due to the high concentration of radium and thorium.

When assessing radon risk, one must always remember that the contribution of radon itself to exposure is relatively small. With radioactive equilibrium between radon and its daughter decay products (DPR), this contribution does not exceed 2%. Therefore, the radiation dose to the lungs from radon DPR is determined by a value equivalent to the equilibrium volumetric activity (ERVA) of radon:

C Rn eq = n Rn F Rn = 0.1046n RaA + 0.5161n RaB + 0.3793n RaC,

where n Rn, n RaA, n RaB, n RaC are the volumetric activities of radon and its DPR Bq/m3, respectively; F Rn is the equilibrium coefficient, which is defined as the ratio of the equivalent equilibrium volumetric activity of radon in the air to the real volumetric activity of radon. In practice, always F Rn< 1 (0,4–0,5).

Standards for EROA of radon in the air of residential buildings, Bq/m:

Another source of radon indoors is natural gas. When gas burns, radon accumulates in the kitchen, boiler rooms, and laundry rooms and spreads throughout the building. Therefore, it is very important to have fume hoods in places where natural gas is burned.

In connection with the construction boom observed in the world today, the danger of radon contamination must be taken into account when choosing both building materials and places to build houses.

It turns out that alumina, used for decades in Sweden, calcium silicate slag and phosphorus gypsum, widely used in the manufacture of cement, plaster, and building blocks, are also highly radioactive. However, the main source of radon indoors is not building materials, but the soil under the house itself, even if this soil contains quite acceptable radium activity - 30-40 Bq/m3. Our houses are built as if on a sponge soaked in radon! Calculations show that if in an ordinary room with a volume of 50 m3 there is only 0.5 m3 of soil air, then the radon activity in it is 300-400 Bq/m3. That is, houses are boxes that trap radon “exhaled” by the earth.

The following data on the content of free radon in various rocks can be given:

When constructing new buildings, it is (must be) provided for the implementation of radon protection measures; responsibility for carrying out such activities, as well as for assessing doses from natural sources and implementing measures to reduce them, by the Federal Law “On Radiation Safety of the Population” N3-F3 of January 9, 1996. and Radiation Safety Standards NRB-96 dated April 10, 1996, developed on its basis, is entrusted to the administration of territories. Main directions (events) of Regional and Federal programs “Radon” 1996-2000. the following:

· Radiation-hygienic inspection of the population and national economic facilities;

· Radioecological support for the construction of buildings and structures.

· Development and implementation of measures to reduce public exposure.

· Assessment of health status and implementation of preventive medical measures for radiation risk groups.

· Instrumentation, methodological and metrological support of work.

· Information Support.

· Solving these problems requires significant financial costs.

CONCLUSION

There are many unresolved issues regarding the radon problem. On the one hand, they are of purely scientific interest, and on the other hand, without solving them it is difficult to carry out any practical work, for example, within the framework of the Federal Radon program.

Briefly, these problems can be formulated as follows.

1. Models of radiation risks from radon exposure were obtained based on an analysis of data on exposure of miners. It is still unclear how valid this risk model is to apply to exposure in homes.

2. The problem of determining effective radiation doses when exposed to DPR radon and thoron is quite ambiguous. For a correct transition from the EROA of radon or thoron to the effective dose, it is necessary to take into account factors such as the fraction of free atoms and the distribution of activity over aerosol sizes. Currently published estimates of connectivity sometimes differ by as much as a factor.

3. There is still no reliable formalized mathematical model that describes the processes of accumulation of radon, thoron and their DPR in the indoor atmosphere, taking into account all routes of entry, parameters of building materials, coatings, etc.

4. There are problems associated with clarifying the regional features of the formation of radiation doses from radon and its DPR

1. Andruz, J. Introduction to Environmental Chemistry. Per. from English – M: Mir, 1999. – 271 p.: ill.

2. Akhmetov, N.S. General and inorganic chemistry. Textbook for universities / N.S. Akhmetov. – 7th ed., erased. – M.: Vyssh.shk., 2008. – 743 p., ill.

3. Butorina, M.V. Engineering ecology and management: Textbook / M.V. Butorina et al.: ed. N.I. Ivanova, I.M. Fadina.- M.: Logos, 2003. – 528 p.: ill.

4. Devakeev R, Inert gases: history of discovery, properties, application. [Electronic resource] / R. Devakeev. – 2006. – Access mode: www.ref.uz/download.php?id=15623

5. Kolosov, A.E. Radon 222, its effect on humans. [Electronic resource] / A.E. Kolosov. Moscow secondary school named after Ivan Yarygin, 2007. – Access mode: ef-concurs.dya.ru/2007-2008/docs/03002.doc

6. Koronovsky N.V., Abramov V.A. Earthquakes: Causes, consequences, forecast // Soros Educational Journal. 1998. No. 12. P. 71-78.

7. Cotton, F. Modern inorganic chemistry, part 2. Per. from English / F. Cotton, J. Wilkinson: ed. K.V. Astakhova.- M.: Mir, 1969. –495 pp.: ill.

8. Nefedov, V.D. Radiochemistry. [Electronic resource] / V.D. Nefedov and others - M: Higher School, 1985. – Access mode: http://www.library.ospu.odessa.ua/online/books/RadioChimie/Predislov.html

9. Nikolaikin, N.I. Ecology: textbook for universities [Test]/N.I. Nikolaikin.- M.: Bustard, 2005.- p.421-422

10. Utkin, V.I. Gas respiration of the Earth / V.I. Utkin // Soros Educational Journal. - 1997. - No. 1. P. 57–64.

11. Utkin, V.I. Radon and the problem of tectonic earthquakes [Electronic resource] / V.I. Utkin Ural State Vocational Pedagogical University, 2000. – Access mode: http://www.pereplet.ru/obrazovanie/stsoros/1133.html

12. Utkin, V.I. Radon problem in ecology [Electronic resource] / V.I. Utkin Ural State Vocational Pedagogical University, 2000. – Access mode: http://209.85.129.132/search?q=cache:zprKCPOwKBcJ:www.pereplet.ru/nauka/Soros/pdf

13. Khutoryansky, Ya, Radon portrait: version of the Ural ecologists / Ya. Khutoryansky // Construction complex of the Middle Urals. -2003. -No. 1. From 52-55.

Literature

INTRODUCTION

GENERAL INFORMATION ABOUT RADON

The “miner’s consumption” was finally dealt with only in 1937, having established that this disease is nothing more than a form of lung cancer caused by high concentrations of radon.

OPENING HISTORY