Radionuclides: truth and myths
Mar 26, 2018
Radionuclides are groups of atoms possessing the radioactivity property, with a certain mass number, atomic number and energy status of the nucleus.
Radionuclides have found wide application in all fields of engineering, science and other branches of the national economy.In the practice of medicine, radionuclides have been used to diagnose diseases, sterilize drugs, tools and other products.A number of prognostic and therapeutic radiopreparations have been developed.
The benefits and application of radionuclides in medicine are described in detail in this video:Contents: About radionuclide classifications Where in the human body are radionuclides How radionuclides are released About the harmful effects of radionuclides per person The effects of strontium-90 and cesium-137 on humansWhat products contain radionuclides About radioprotective properties of food and drug substances Products that have the property of removing radionuclides How to better handle food products for PtsRadioactive waste removal What to do if radionuclides are damaged Interesting facts of the consequences of radioactive contamination
On radionuclide classifications
Radioactive isotopes by properties belong to different categories.We will only touch upon the most important of them.
Radioisotopes are divided into:
- artificial, formed as a result of conducted nuclear reactions due to human activities.
The second is obtained from all the elements of the periodic table.The total number of them reaches 2000 and continues to increase.The natural elements are much smaller, about 100.
On the stability of nuclei, radionuclides are classified into:
- short-lived - with a half-life of less than 10 days;
- long-lived - with a long half-life.
In recent years, radioisotopes have been increasingly used in the national economy with a period of complete decay in a few minutes, which makes them practically harmless.
For radiation toxicity, radionuclides fall into 4 categories:
- A - the most highly toxic for humans.These are isotopes of heavy elements whose nuclei are prone to spontaneous decay.They have relatively large half-lives.Also these radioactive substances tend to accumulate in different organs of the body;
- B - radionuclides of high toxicity;
- B - radioisotopes of medium toxicity;
- D - radiation isotopes of low toxicity.
Radioactive reactions are divided into alpha decay - spontaneous change in the structure of the nucleus with the appearance of alpha particles and beta decay with the emission or absorption of electrons, positrons, neutrinos or antineutrinos.
We will not dwell on more detailed characteristics of the decay species.We will try to touch more on the properties of radioelements.
Natural radionuclides are found in rocks, soil layers, aquatic natural and artificial reservoirs.Together with cosmic radiation, they constitute the external radiation background of .
Uranium, thorium isotopes enter the body with ingestion of food, water, inhaled air and serve as sources of internal irradiation.
The natural radiation background is described in detail in this video:Technogenic background radiation
Nuclear reactors and accelerators of charged particles give the an artificial radiation background.
Note: One of the important properties of radionuclides is the half-life of .The processes taking place in radionuclides lead to a decrease in the number of nuclei by a factor of two, thereby reducing the radiation activity of the isotope.
In tissues and organs, radionuclides come through inhalation of air, food intake, scratches, wounds, burns.
Where in the human body are radionuclides
Radioactive isotopes have their "favorite" places in the human body.
There are 4 groups in this property:
- Radionuclides evenly distributed over the body tissues - cesium 134, cesium 137( radiocesium), sodium 24, etc.
- Deposited in bone tissue - strontium 89, 90, barium 140, radium 226, 224, calcium 40, yttrium.
- Accumulating in the reticulo-endothelial organs( red bone marrow, lymph nodes, liver, spleen) - cerium, promethium, americium, plutonium, lanthanum.
- Organotropic - iodine isotopes in the thyroid gland, iron in erythrocytes, zinc in the pancreas, molybdenum in the iris of the eye.
As radionuclides are released
The bulk of radioactive isotopes is excreted from the body by the intestine.Soluble( cesium and tritium) come out through the urinary system.Gaseous elements are removed by the skin and respiratory organs.The main part of radionuclides is excreted a few days after receipt.Isotopes that have a large atomic mass, radioactive colloids( polonium, radium, uranium) are delayed.These elements enter the liver and into the bile ducts.
Please note : the unit of measurement of the radionuclide removal process from the body is , the elimination half-life of , characterized by the release of half of the radioactive substance that has entered the human body.
For example: the iodine radioisotope located in the thyroid gland has a half-life of 138 days, and in the kidneys - 7 days, in the bone tissue - 14 days.
Radioactive elements are slowly removed from the bone tissue.In soft tissues, the output process is much faster.We are talking about cesium, molybdenum, iodine, etc. But such substances as strontium, zirconium, plutonium, etc. are significantly more problematic, settling in human bones for a long time.
About harmful effects of radionuclides on humans
Radioactive isotopes in the human body have an effect that stops the growth and division of cells, damages normal biochemical cycles, causes disruption of DNA structural bonds, destroys the genetic code.As a result, cells undergo destruction.
Free radicals that enter the body in large doses cause serious tissue damage.In small doses, they can disrupt the maturation and development of cells, cause malignant neoplasms.Genetic changes can lead to serious hereditary diseases that will manifest in offspring.
Let's consider the mechanism of destructive influence of some radionuclides.
The action of strontium-90 and cesium-137 on the human body
Strontium-90 accumulates in bone tissue, bone marrow, hematopoiesis in case of ingestion.Damaging effect causes anemia( anemia).Its action lasts for decades, since the half-life of the element is 29 years, and half-life is 30 years.When ingested, strontium is concentrated in the blood for 15 minutes, completely settling in the target organs after 5 hours.The removal of this radioactive substance is a difficult task.While there are no effective methods, to resist its effects.
Cesium-137 is the second most common and dangerous for human radionuclide.It has the property of accumulating in plant cells and already penetrating the human body through the stomach and intestines into food.The half-life is 30 years.Favorite location - the muscles.It is displayed very slowly.
Which products contain radionuclides
The greatest amount of radionuclides is found in bakery products.After them, milk and dairy products followed, followed by vegetables and fruits.The least amount of radioisotopes in meat and fish, especially in seafood.That is, products of animal origin are cleaner in terms of radiation safety than vegetable products.
Sea water contains fewer radioactive elements than fresh water.Virtually free from isotopes artesian water.The remaining reservoirs can contain high doses, depending on their geographical location and other factors( pollution).
The permissible levels of cesium-137 and strontium-90 radionuclides are given in the table:
On the radioprotective properties of food and drug substances
Radiostability of the human body is increased by polysaccharides, lipopolysaccharides of tea leaves, grapes, medical alcohol, vitamins, minerals, practically all groups of enzymes, many hormones.
Antibiotics, narcotic substances, vitamins of artificial production are shown to be resistant to the action of radiation sources.
Products that have the property of removing radionuclides
Consider the main groups of food products that are capable of exerting an antiradiation effect and accelerating the release of isotopes from human tissues.
These products include:
- egg shell - the calcium in its composition removes radioactive strontium.Use it up to 5 grams per day.Pre-shredded to the state of the shell powder is added to the food;
- bread products from rye flour.In them there is a phytin binding strontium, which enters the digestive tract with food;
- citrus, chokeberry, hawthorn berries, sea buckthorn, licorice.These plants and their fruits contain flavonoids, which also have radionuclide removal properties.
Do you want to know what products contribute to removing radionuclides from the body?See video review:
How to better treat food products for radioactive purification
Conventional mechanical methods for processing food products help to remove strontium and cesium on their surface.It's enough just to wash them in cold water and clean them of dirt.
In vegetable crops, it is necessary to cut the top part of the fruit, since it accumulates about 80% of toxic and radioactive substances.Cabbage must be cleaned from the upper leaves, and also do not use the internal "stump".
Heat treatment removes about half of the radionuclides contained in the product.But the frying is just the opposite, delays them.
Meat and fish semi-finished products should be soaked in water with vinegar before cooking.Meat broth is recommended to be drained, in it after cooking toxins and radioactive isotopes accumulate.If it is necessary to prepare the broth, pour the meat in cold water, cook for 10 minutes, then broth the broth.Water to collect fresh, and boil the meat until ready.In the resulting broth of harmful radioactive substances will be less than twice.
The number of radioactive elements decreases with small cutting of meat and soaking it in water for several hours.It should be remembered that with this treatment, the useful properties of the product are lost.
Pre-soaking of mushrooms removes 30% of cesium, and cooking up to 90%.Strontium is not practically eliminated with such treatments.
The most "clean" from radioactivity are refined varieties of vegetable oil, sugar and starch.
The processing of milk to the state of oil almost completely deprives it of strontium, and cesium is rendered harmless by processing milk into cheese, powdered substances.
Jerusalem artichoke is a fruit that does not accumulate radioactivity.
The ear can absorb radionuclides from bones, fins and fish scales.For the same reason, the radiation hazard can also be represented by canned foods in which the semi-finished product is processed under pressure using high temperatures.This leads to softening of inedible parts of fish, in which radionuclides are usually concentrated.
The products of grain bran also accumulate radioisotopes of strontium.
What to do with radionuclide damage
Radioactive isotopes that enter the body require an acceleration of the process of their elimination.The most important factor of resistance to harmful effects of radionuclides is the state of the immune system.The existing natural radiation background, affecting humans for thousands of years, created natural protection mechanisms that have the effect of neutralizing radionuclides.We are talking about the removal of foreign substances bile, intestines, kidneys, liver.
If the process of entering the body of a radiation group of substances is of a permanent nature, then it is necessary:
- take calcium preparations with multivitamins that promote bone tissue protection;
- to eat foods high in potassium - peas, beans, lentils, dried fruits.The substances in them contribute to the excretion of cesium from the body;
- add to the diet of chicken eggs, milk.The calcium in them is able to remove strontium;
- has fruits and vegetables with a high content of pectins that bind radionuclides
- to take diuretics;
- maintain an active water regime.Drink mineral water, which will help get rid of the radioactive isotopes of potassium, sodium and magnesium.
Interesting facts of the consequences of radioactive contamination
Accidents at nuclear power plants, nuclear weapons testing, nuclear laboratory experiments leave their mark in the atmosphere, water, soil.Scientists found out that in this way about 20 radionuclides are released into the external environment.Most of them do not present long-term harm, as they are inactivated for several weeks and months.First of all, we are talking about isotopes of noble gases, which form the basis of a radioactive cloud.They are capable of harming people's health.
The next dangerous element was the iodine-131 isotope.It quickly accumulated in foods, especially in milk.It should be noted that the standards of radiation safety in our country are much tougher than in Europe.
An element that is not as aggressive in terms of its harmful significance as compared to the above substances, but more stable, is plutonium.He poses a particular danger as an opportunity to cause serious lung diseases.
Still, the cesium and strontium, which we have already disassembled, are still more harmful, and they persist in the body for decades.
Note: Against the backdrop of the ongoing tragedies( the Chernobyl nuclear power plant accident, the explosion at the nuclear power plant "Fukushima-1, other man-made disasters"), a whole galaxy of charlatans appeared that intimidated people with the stories that huge territories were contaminated with radioactivity and allpopulation.They offer money for a hundred percent purification of the body of radioactive substances.Is there any rational grain in these statements - a topic for a separate serious conversation.In most cases, fraud is based on "miraculous" methods.Therefore, any person exposed to radiation contamination should seek help only from the official medicine.
Alexander Lotin, radiologist,