News and SocietyEnvironment

Radioactive soil contamination and its consequences

Active human activity very often adversely affects the surrounding world of animate and inanimate nature. The rapid development of industry, the intensive development of agriculture, the difficulties of recycling waste - all this seriously threatens the ecology of the planet. With the development of nuclear energy and the improvement of nuclear weapons, another problem arose: radioactive contamination of soils, reservoirs, and the atmosphere.

Identifying the problem

Radioactive contamination of the soil is the excess of the concentration of radionuclides in it over the indices of the maximum permissible norm due to anthropogenic activity.

Contaminated areas are characterized by a significant excess of external and internal exposure doses. To denote the norm of ionizing cure, the International Radiation Protection Commission (ICRP) introduced an average annual radiation dose, which for the soil and rocks is 0.25-0.5 microsievert per year (mSv / g). This standard determines the amount of radiation safe for human health and many times below the value that can lead to the death of a living organism for a further 30 days.

Causes

How does radioactive contamination of soils occur? Sources of pollution are two groups of radionuclides:

  • Technogenic;
  • Natural.

It is known that the soil contains natural radionuclides. But their concentration is significantly increased due to the extraction, storage of natural raw materials, processing, fertilization, production, burning of coal, use of ashes as fertilizing plants or for the production of building materials, etc.

Due to the rapid production and use of fertilizers, the number of radioactively contaminated soils increases every year. For example, the issue of increasing the concentration in the soil of radionuclides due to the use of potassium and phosphorus fertilizers has not been adequately studied.

Artificial radionuclides are massively included in the components of the planet's biosphere due to nuclear explosions.

Thus, the main causes of radioactive contamination of the soil cover are:

  • Intensive development of agricultural land;
  • Heavy industry;
  • Development of deposits of natural resources;
  • Disposal of radioactive waste;
  • Radiation emissions of nuclear power plants;
  • Nuclear weapon test.

Radioactive contamination of soils: consequences of infection

There are many negative consequences of soil contamination:

  • Direct negative impact of radioactive substances on animals, vegetation and humans;
  • A significant limitation of the ability to use soil resources for agricultural purposes. After all, all the products that are received from such a land plot have a higher level of concentration of radioactive substances due to contamination of open water bodies and groundwater, where harmful compounds are leached from the soil. Severe pollution can lead to the inability to use fresh water not only for drinking and cooking, but also for watering cattle or watering agricultural land.

Many scientists argue that radiation damage to the environment leads to the complete death of biogeocenosis and populations. This occurs at a high level of contamination. Such areas are fixed mainly near the places where the radiation was released and, as a consequence, the radioactive contamination of the soil. Chernobyl is a zone of alienation after the accident at the Chernobyl nuclear power plant. Then hundreds of hectares received the strongest dose of radiation, as a result of which they were completely withdrawn from human life.

Deep processes

The soil absorbing complex sorts radioactive substances. In addition, he keeps them for a long time.

Radionuclides in soil are characterized by:

  • Properties of chemically active isotopes;
  • Properties and composition of the soil itself;
  • Properties of radionuclides in fallout;
  • Climatic indicators;
  • Features of the landscape.

Radionuclides on the surface of the soil come in the form of aerosols, minerals, fuel particles, etc. The maximum part of their soluble fractions in the composition of global deposition is 30-90%. The highest in cesium and strontium. How will behave radionuclides in the future - no one knows. Dynamic equilibrium increases as the solubility of their deposition decreases. The introduction of soluble organic substances into the soil and the special acidification of the medium affect the increase in the migration of radionuclides, which is used to purify it.

The mobility of radiation contamination depends on:

  • Mineralogical composition;
  • Presence in the soil of geochemical barriers;
  • Granulometric composition ;
  • Properties of humus;
  • Reaction of the medium.

Horizontal redistribution of radionuclides

To predict the possible consequences of radioactive contamination of soil, it is very important to know the specific features of migration of radionuclides.

Redistribution of radionuclides in the soil occurs in a horizontal and vertical direction in a natural way and for reasons of anthropogenic activity.

Horizontal migration occurs due to:

  • Aeolian transfer (the name comes from the name of the wind god Eola);
  • Flood of flood waters, which is the reason for more intensive pollution of lowlands and wetlands;
  • Livelihoods of animals (earthworms, wild boars, moles and other "digging");
  • Traffic;
  • Preparation of green forage in contaminated meadows;
  • Forest fires, which are a very powerful factor in the transport of isotopes.

The minimum horizontal migration is observed in forest cenoses, and the maximum in agrocenoses with light soils. Horizontal redistribution, on the one hand, reduces the level of soil contamination with radioactive nuclides, on the other - it expands the range of their distribution.

Vertical Migration

As for vertical redistribution, in all types of soils it occurs slowly. The linear speed of this process is from tenths to two centimeters per year. The soil in this case acts as a biogeochemical barrier. Studies conducted in the Chernobyl zone have shown that the main part of radionuclides remains within the upper soil layer (about 10 cm) for a long time. And in the forest part of this zone, radioactive substances have accumulated in the litter (foliage, needles) and the lower soil layer (about 1-2 cm).

Vertical migration of radionuclides depends on such factors:

  • Volcanic eruptions;
  • Rains, the transfer of moisture by runoff and evaporation;
  • Transfer of root systems of plants;
  • Human activity - plowing, irrigation.

The most polluted territories on the planet

There are hundreds of radioactively contaminated territories on the planet. Serious danger is the territory of Henford in the state of Washington, USA. Here in the middle of the last century a huge complex was built, dealing with the world's first nuclear development. As a result of his activities, an area of 518 sq. M. Km.

Soils in Somalia were used for illegal disposal of nuclear waste. The Semipalatinsk test site in Kazakhstan, where nuclear tests were conducted, is one of the most radiation-hazardous areas in the world. In the city of Mailuu-Suu, Kyrgyzstan, uranium mining was established on an all-Union scale, which led to an extremely high concentration of radioactive isotopes in the area of the mines.

The well-known Chernobyl zone is a dead zone where radioactive contamination of soils has happened for many hundreds of kilometers. ChNPP is not the only nuclear power plant in the world where a nuclear catastrophe of a global scale has occurred. This happened in Fukushima, Japan. Here, the earthquake and tsunami in March 2011 caused an accident at the nuclear power plant, as a result of which a huge area was damaged.

The industrial complex "Mayak" in Russia in the secret city of Chelyabinsk-40 near the town of Kyshtym suffered from the accident in 1957. Its consequences were the radiation pollution of 25 thousand hectares of arable land. Such a catastrophic situation has developed around the Siberian Chemical Combine in the Tomsk region, Russia.

Features of the use of contaminated areas

In the soil, radionuclides with a long decay period mainly accumulate: promethium-147, cerium-144, cesium-137, ruthenium-106 and 103, strontium-90. The most dangerous for living organisms is strontium-90. Therefore, on the fields contaminated with radiation, agrochemical, agrotechnical and other measures are carried out, which can reduce the transfer of dangerous compounds from the soil to the plants. To this end, the top layer of the soil is also cut off, followed by burial.

An effective measure is the sowing of plants of certain varieties and species that are characterized by a minimum level of accumulation of radionuclides. Everyone knows that in animal husbandry for fattening, only clean feed should be used. Also used are special additives of sorbents, which suppress the transfer of radioactive substances into the composition of milk.

Reclamation works are aimed at reducing the intake of radionuclides in plants. To do this, sorbents are introduced into the soil, such as: vermiculite, zeolite, mineral and organic additives, lime. In agriculture, the reduction of accumulation in the plant of radionuclides occurs by means of agrotechnical methods. Conduct plantation plowing, with the rotation of the formation. This technique of soil cultivation leads to a deepening of radioactive contamination. Thanks to this, the accumulation of substances in plants decreases by a factor of 24. In agriculture, the structure of the crop rotation should be changed. It is better to start growing technical crops that are not used in food.

An alternative method of using a contaminated area is to eliminate any specific impact. For example, you can create special reserves. With a pronounced radiation background , the forest is planted at the site of infection, mainly pine.

Security measures

Security measures in the territories where there is radiation contamination of the soil are directed to reduce the negative impact of radiation. The following actions are carried out:

  • The development of a strategy for the use of products and territories at the national or international level, depending on the extent of pollution and the potential risk of contamination of surrounding areas;
  • Meliorative, agrotechnical measures;
  • Chemical disinfection;
  • Use of sorbents;
  • Restriction of human activity;
  • Informing the population about possible danger;
  • Restricting the export of any product from a hazardous area.

The period of validity of these restrictions depends primarily on the density of contamination. In addition, pay attention to the exposure dose of radiation. This period can last from several weeks to many decades. Thus, ecologists reduce radioactive contamination of soils and its consequences.

Similar articles

 

 

 

 

Trending Now

 

 

 

 

Newest

Copyright © 2018 en.birmiss.com. Theme powered by WordPress.