Soil contamination of the soil and its consequences. Assessment of soil pollution

Soil is a special natural formation that ensures the growth of trees, crops and other plants. It is difficult to imagine life without our fertile soils. But how does modern man refer to soils? Today, soil contamination by humans has reached colossal proportions, so the soil of our planet is in dire need of protection and protection.

Soil - what is it?

Protection of soils from pollution is impossible without a clear understanding of what soil is and how it is formed. Let's consider this issue in more detail.

Soil (or soil) is a special natural formation, an indispensable component of any ecosystem. It is formed in the upper layer of the parent rock, under the influence of the sun, water, and also vegetation. Soil is a bridge, a link that connects the biotic and abiotic components of the landscape.

The main processes, as a result of which soil is formed, is the weathering and vital activity of living organisms. As a result of the processes of mechanical weathering, the parent rock is destroyed and gradually crushed, and living organisms fill this non-living mass with organic substances.

Soil contamination by man is one of the main problems of modern ecology and nature management, which was especially acute in the second half of the 20th century.

Soil structure

Any soil consists of 4 main components. It:

• Rock (base of the soil, about 50% of the total mass);
• Water (about 25%);
• Air (about 15%);
• Organic substances (humus, up to 10%).

Depending on the ratio of these components in the soil, the following types of soils are distinguished:

• Stony;
• Clayey;
• Sandy;
• Humic;
• Saline soils.

The key property of the soil, which distinguishes it from any other component of the landscape, is its fertility. This is a unique property that satisfies plants in essential nutrients, moisture and air. Thus, the soil ensures the biological productivity of all vegetation and the yield of agricultural crops. That is why soil and water pollution is such an acute problem on the planet.

Soil cover studies

Soil research deals with a special science - soil science , the founder of which is considered Vasily Dokuchaev - a scientist of world renown. It was he who, at the end of the nineteenth century, first noted that the soils spread quite naturally along the earth's surface (latitudinal zoning of the soil), and also called clear morphological signs of the soil.

V. Dokuchaev considered the soil as an integral and independent natural formation, which none of the scientists did before it. The most famous work of the scientist - "Russian black earth" in 1883 - is a reference book for all modern soil scientists. V. Dokuchaev conducted a thorough research of the soils of the steppe zone of modern Russia and Ukraine, the results of which formed the basis of the book. In it, the author singled out the main factors of soil formation: the parent breed, the relief, the climate, age and the plant world. The scientist gives a very interesting definition of the concept: "the soil is a function of the parent rock, the climate and organisms, multiplied by time."

After Dokuchaev, the study of soils was also actively pursued by other well-known scientists. Among them: P. Kostychev, N. Sibirtsev, K. Glinka and others.

The importance and role of soil in human life

The phrase "earth-nurse", which we hear very often, is not symbolic or metaphorical. This is really so. This is the main source of food for humanity, which, in one way or another, gives about 95% of all food. The total area of all land resources of our planet is currently 129 million km ² of land, of which 10% are occupied by arable land, and another 25% are hayfields and pastures.

To study the soil began only in the XIX century, but people knew about their beautiful property - about fertility, from the most ancient times. It is the soil owes its existence to all plant and animal organisms on Earth, including man. It is not by chance that the most densely populated areas of the planet are the regions with the most fertile soils.

Soils are the main resource of agricultural production. Many conventions and declarations adopted at the international level call for rational and careful treatment of the soil. And this is obvious, because the total pollution of land and soil threatens the existence of all mankind on the planet.

The soil cover is the most important element of the geographic envelope of the Earth, responsible for all processes in the biosphere. Soil accumulates a huge amount of organic matter and energy, thus fulfilling the role of a giant biological filter. This is the key link in the biosphere, the destruction of which will disrupt its entire functional structure.

In the 21st century, the burden on soil cover has increased several times, and the problem of soil contamination has reached the level of primary and global importance. It is worth noting that the solution to this problem depends on the coherence of the actions of all the states of the world.

Pollution of land and soil

Soil pollution refers to the process of soil cover degradation, in which the content of chemicals in it significantly increases. Indicators of this process are living organisms, in particular, plants that are the first to suffer from a violation of the natural composition of the soil. The reaction of plants depends on the level of their sensitivity to such changes.

It should be noted that in our country criminal liability is provided for the contamination of human land. In particular, Article 254 of the Criminal Code of the Russian Federation sounds like "Corruption of the Earth".

Typology of pollutants

The main soil contamination began in the twentieth century with the rapid development of the industrial complex. Under the pollution of soils are understood as the introduction into the soil of atypical components for it - the so-called "pollutants". They can stay in any aggregate state - liquid, solid, gaseous or complex.

All soil contaminants can be divided into 4 groups:

• Organic (pesticides, insecticides, herbicides, aromatic hydrocarbons, chlorine-containing substances, phenols, organic acids, petroleum products, gasoline, varnishes and paints);
• Inorganic (heavy metals, asbestos, cyanides, alkalis, inorganic acids and others);
• Radioactive;
• Biological (bacteria, pathogenic microorganisms, algae, etc.).

Thus, the main soil contamination is carried out with the help of these and some other pollutants. The increased content of these substances in the soil can lead to negative and irreversible consequences.

Sources of land pollution

To date, you can name a large number of such sources. And their number is increasing every year.

We list the main sources of soil contamination:

1. Residential houses and communal services. This is the main source of land pollution in cities. In this case, soil contamination by a person occurs through household waste, food debris, construction debris and household items (old furniture, clothes, etc.). In large cities, the question "where to put the garbage?" Turns into a real tragedy for the city authorities. Therefore, on the outskirts of cities grow huge kilometer dumps, where all household waste is taken. In the developed countries of the West, the practice of recycling garbage at special facilities and plants has long been introduced. And this is where a lot of money is earned. In our country so far, such cases, alas, are rare.
2. Factories and plants. In this group, the main sources of soil pollution are the chemical, mining and engineering industries. Cyanides, arsenic, styrene, benzene, clumps of polymers, soot - all these terrible substances fall into the ground in the vicinity of large industrial enterprises. The big problem now also is the problem of recycling tires, which are the cause of large fires, which are very difficult to extinguish.
3. Transport complex. Sources of land pollution in this case - lead, hydrocarbon, soot, as well as nitrogen oxides. All these substances are released during the operation of internal combustion engines, then they settle on the surface of the earth and are absorbed by the plants. Thus, they also fall into the soil cover. At the same time, the degree of soil contamination will be as high as possible along major highways and near automobile interchanges.
4. Agroindustrial complex. Receiving food from the ground, we at the same time poison it, paradoxically as it may sound. Soil contamination by humans here occurs through the introduction of fertilizers and chemicals into the soil. That's how horrible substances get to the ground - mercury, pesticides, lead and cadmium. In addition, excess chemicals can be washed off the fields by rain, falling into permanent waterways and underground water.
5. Radioactive waste. The pollution of the soil with waste from the nuclear industry carries a very great danger. Few people know that during nuclear reactions to nuclear power plants, about 98-99% of the fuel is wasted. These are products of uranium fission - cesium, plutonium, strontium and other elements that are extremely dangerous. A very big problem for our country is the burial of these radioactive wastes. Every year around 200 thousand cubic meters of nuclear waste are generated in the world.

The main types of pollution

Soil contamination can be natural (for example, during volcanic eruptions), or anthropogenic (man-made), when pollution occurs through the fault of a person. In the latter case, substances and products that are not characteristic of the natural environment and negatively affect ecosystems and natural complexes enter the soil.

The process of classification of soil contamination types is very complicated, different classifications are given in different sources. But still the main types of soil contamination can be represented as follows.

Household pollution of soils is pollution of soils with garbage, waste and emissions. This group includes pollutants of various types and in different aggregate states. They can be either liquid or solid. In general, this type of pollution is not too dangerous for soil, but excessive accumulation of household waste clogs the terrain and prevents the normal growth of plants. The most acute problem of household pollution of soils is in megacities and large cities, as well as in settlements with uninvolved garbage disposal system.

Chemical contamination of soils is, first of all, contamination with heavy metals, as well as pesticides. This type of pollution already poses a great danger for a person. After all, heavy metals have the property of accumulating in a living body. Soils are contaminated with heavy metals such as lead, cadmium, chromium, copper, nickel, mercury, arsenic and manganese. A big polluter of the soils is gasoline, which contains a very toxic substance - tetraethyl lead.

Pesticides are also very dangerous substances for the soil. The main source of pesticides is modern agriculture, which actively uses these chemicals in the fight against beetles and pests. Therefore, pesticides accumulate in the ground in a huge amount. For animals and humans, they are no less dangerous than heavy metals. So, a highly toxic and very stable drug DDT was banned. It is capable of not decomposing in the soil for decades, scientists have found its trace even in the Antarctic!

Pesticides are very harmful to soil microflora: bacteria and fungi.

Radioactive contamination of soils is soil contamination by waste from nuclear power plants. Radioactive substances are extremely dangerous, as they easily penetrate the food chains of living organisms. The most dangerous radioactive isotope is strontium-90, which is characterized by a high yield during nuclear fission (up to 8%), and also by a large (28 years) half-life. In addition, it is very mobile in the ground and can be deposited in the bone tissue of humans and various living organisms. Other dangerous radionuclides can also be cesium-137, cerium-144, chlorine-36.

Volcanic pollution of soils - this type of pollution belongs to the group of natural. It consists in getting into the soil of toxic substances, soot and combustion products, which occurs as a result of volcanic eruptions. This is a very rare type of soil pollution, which is typical only for certain small areas.

Mycotoxic contamination of soils is also not technogenic and has a natural origin. The source of pollution here are some species of fungi that release dangerous substances - mycotoxins. It is worth noting that these substances represent the same great danger for living organisms, like all the others listed above.

Soil erosion

And a major problem for the preservation of the fertile layer of soils was and remains erosion. Every year it "eats" large areas of fertile soil, while the rate of natural soil cover restoration is much lower than the rate of erosion processes. Scientists have already thoroughly studied the features of these processes and found measures to combat them.

Erosion can be:

• Aquatic
• Wind

Obviously, in the first case, the leading erosion factor is the flowing water, and in the second - the wind.

More widespread and dangerous is water erosion. It begins with the appearance on the earth's surface of a small, barely noticeable gully, but after every heavy rain this scum will expand and increase in size until it turns into a real ditch. For one summer period alone, a moat depth of 1-2 meters can appear on an absolutely level surface! The next stage of water erosion is the formation of a ravine. This form of relief is characterized by a large depth and branched structure. Ravines destroy catastrophically fields, meadows and pastures. If you do not fight with a ravine, sooner or later it will turn into a beam.

Water erosion processes are more active in a steppe region with a rugged terrain, where there is very little vegetation.

The cause of wind erosion is storms and dry winds, which are capable of blowing up to 20 centimeters of the upper (most fertile) soil ball. The wind carries soil particles over long distances, forming in certain places deposits up to 1-2 meters in height. Most often they are formed along plantings and forest belts.

Assessment of soil contamination level

An adequate assessment of soil contamination is very important for carrying out a complex of measures to protect the soil cover. It is calculated by complex mathematical calculations, after carrying out a complex of detailed chemical and ecological studies. The evaluation is represented by a complex pollution index Z _c .

Assessment of soil pollution is carried out taking into account several important factors:

• Specificity of pollution sources;
• Complex of chemical elements - soil pollutants;
• Priority of pollutants, according to the list of MPC substances;
• Nature and conditions of land use.

Researchers identify several levels of soil contamination, namely:

1. Allowable (Z _with less than 16).
2. Moderately hazardous (Z _s from 16 to 38).
3. Dangerous (Z _s from 38 to 128).
4. Extremely dangerous (Z _with more than 128).

Soil protection

Depending on the source of pollution and the intensity of its influence, special measures have been developed to protect the soil cover. These measures include:

1. Legislative and administrative (adoption of relevant laws in the field of soil conservation, and control over their implementation).
2. Technological (creation of non-waste production systems).
3. Sanitary (collection, disinfection and disposal of waste and soil pollutants).
4. Scientific (development of new technologies for treatment facilities, assessment and monitoring of soil conditions).
5. Forest reclamation and anti-erosion measures (these are measures for planting special forest shelter belts along the fields, construction of hydraulic structures and proper planting of agricultural crops).

Conclusion

The soil of Russia is a colossal wealth, thanks to which we have food products, and the production is provided with the necessary raw materials. The soil was formed over many centuries. That is why soil protection from pollution is the most important task of the state.

Today, there are a large number of sources of soil pollution: transport, industry, cities, utilities, nuclear power plants, agriculture. The task of scientists, state authorities and public figures is to protect the soil from the harmful effects of all these factors, or at least minimize their harmful impact on soils.