What causes soil pollution with heavy metals: consequences and 6 methods of struggle

Heavy metals are considered common pollutants, the content of which in the soil must be kept under control. What causes soil contamination with heavy metals? The burning of fossil fuels is one of the main reasons for these substances to enter the ground. Other ways are also possible. At the same time, metals with pronounced toxic properties - mercury, cadmium, lead - pose the greatest danger.

What metals pollute the soil

There are several categories of heavy metal hazards. According to the World He alth Organization, the most dangerous substances include mercury, cadmium and lead. The concentration of other elements is no less dangerous.

The key threat of heavy metals lies in the fact that they are hardly excreted from the body and accumulate in it. This causes the formation of toxins. They easily pass from one medium to another without decomposing. In this case, substances cause severe pathologies and often cause irreversible consequences.

Mercury

Soil damage by mercury can be associated with the penetration of pesticides and all kinds of household waste into it. These can be fluorescent lamps and parts of broken measuring instruments.

According to official information, the annual release of mercury exceeds 5,000 tons. This metal is able to enter the human body from contaminated soil. If this is observed systematically, there is a risk of developing complex lesions of internal organs, including the nervous system. If you violate the rules for the treatment of mercury intoxication, there is a risk of death.

Lead

Lead is a great danger to people. It is considered a highly toxic metal. With the extraction of 1 ton of lead, 25 kilograms of the substance enters the environment. A large volume of the element penetrates the soil with exhaust gases.

Fields of soil pollution along the routes exceed 200 meters. When released into the soil, lead is absorbed by cultivated plants, the fruits of which are consumed by people and animals. Excess lead in the body provokes damage to the nervous system, liver, kidneys, brain. The substance is mutagenic and carcinogenic.

Cadmium

Cadmium contamination of soil poses a great danger to people. When it enters the soil, it provokes a curvature of the skeleton and cessation of growth in children. In addition, this metal is considered the cause of severe back pain.

Copper and zinc

The increased concentration of these substances in the soil provokes a slowdown in growth and a deterioration in the fruiting of plants. This results in a sudden drop in yield parameters. People have abnormal processes in the liver, brain, pancreas.

Molybdenum

The increased amount of molybdenum in the structure of the soil provokes dangerous disorders in people. This substance can cause the development of gout. It also often causes various diseases of the nervous system.

Antimony

This substance is found in certain types of ores. It is present in the composition of alloys that are used in various industrial fields. Excess amounts of antimony provoke complex digestive disorders.

Arsenic

The main sources of soil contamination with arsenic are substances that are used to control pests of agricultural plants.These can be herbicides or insecticides. Arsenic tends to accumulate and leads to chronic poisoning. Its compounds cause damage to the skin, nervous system and brain.

Manganese

Soil and plants contain a lot of this element. If an additional amount of manganese penetrates into the soil, its excess amount is created. This negatively affects the work of the human body, causing the destruction of the nervous system.

Excess of other heavy metals is also very dangerous. Thus, the accumulation of these substances in the soil leads to serious consequences for people and the environment.

How to deal with the problem

Before you try to fix the problem, it is important to diagnose the degree of contamination of the soil with heavy metals. For this, different methods are used. Each of them has its own specifics and differs in effectiveness depending on the region.Therefore, the level of harmful substances is assessed depending on potential sources of pollution.

There are the following types of research:

1. Bioindication. In this case, the state of the soil is determined, which is reflected by biological indicators. These include the state of plants in the territory, the activity of soil microorganisms, the reactions of mosses and lichens to processes occurring in the structure of the earth.
2. Determination of the degree of pollution of the snow cover. In industrial areas, microelements penetrate the soil with technogenic dust. It settles and subsequently enters the soil layers. By assessing snow cover in winter, it is possible to determine the approximate amount of metals that enter the soil over a certain time interval.
3. Evaluation of the magnetic susceptibility of the soil. This is a rapid method that allows you to determine the volume of iron oxides present in the soil. These elements are the main carriers of pollution when released into the atmosphere.

In areas where the soil is most contaminated with heavy metals, it is necessary to conduct a count of the number of microorganisms. This parameter displays the parameters of soil activity and the quality of the processes of decomposition and absorption of elements.

To prevent the negative effects of soil pollution with toxic substances, various activities are carried out. The first direction is to reduce the concentration of metals that enter the soil during production along with waste.

The second way to fix problems is to restore soil that has already been negatively affected. To do this, apply methods that help reduce the volume of metals and neutralize them.

To eliminate soil pollution, it is permissible to use physical, biological and chemical methods. The most effective areas include the following:

1. Increasing soil acidity increases the risk of heavy metal contamination. Therefore, the use of organic matter, lime and clay helps to solve the problem to a certain extent.
2. Sowing, mowing and removing certain plants from the ground surface helps to significantly reduce the concentration of harmful metals in the soil structure. In addition, this method is environmentally friendly.
3. Groundwater detoxification also gives good results. To do this, they are pumped out and cleaned.
4. It is important to predict and eliminate the migration of the soluble form of heavy metals.
5. In difficult cases, you need to completely remove the soil layer and replace it with a new one.

Liming

Introducing lime into the soil is considered an effective method. It affects the chemical, biological and physical characteristics of the soil. In combination with lime, trace elements form hardly soluble elements. They dissolve little by little due to chemical absorption.

Plants that are planted in soil treated with lime contain a minimum of metals. This substance leads to a decrease in the mobility of heavy metal particles. At the same time, their solubility increases.

Claying

This procedure has a beneficial effect on the structure of the soil, affecting the mobility of heavy metals. When using clay, which includes mineral additives, the cation exchange capacity of the soil increases. Clay absorbs metals more strongly than organic components. The degree of impact is determined by the characteristics of the pollutants.

Soil flushing

With a high content of toxic substances, it is worth using the method of washing the soil. For this, reagents are used. This method has a number of disadvantages. These include the risk of heavy metals entering groundwater and removing valuable substances from the soil structure.

As a reagent, soluble iron s alts are used, which are characterized by a low degree of toxicity to crops. After washing, it is required to perform liming of the substrate and add minerals and organic matter.

Natural and artificial sorbents

This method consists in the introduction of zeolites. They are natural sorbent elements that increase the amount of absorbed trace elements. Metabolic fungi are used for bioremediation. It is also acceptable to use worms and insects. The effectiveness of this procedure is determined by the general condition of the soil, its degree of contamination and composition.

Biologically active waste and activated carbon are used as synthetic sorbents. Ion exchange resins are also highly efficient.

Mineral fertilizers

Ingredients of mineral preparations affect the mobility of metals. But this method is not always beneficial, and if used incorrectly, it can cause great harm. A side effect of top dressing is an increase in acidity parameters, which negatively affects the mobility of toxic substances.

For detoxification, fluoride-containing drugs are used. This method can be used for severe pollution. With a small content of harmful elements, the use of such compounds will only aggravate the general condition of the soil.

Organic fertilizers

Soil saturated with organic matter is less sensitive to the influence of negative factors. Organic substances provoke an increase in fertility and an increase in the number of useful elements that crops need for normal development.

Consequences of accumulation of heavy metals

Excessive amount of harmful metals in the earth leads to negative effects. Of particular danger are pathologies that appear in case of penetration of substances into the body. A large number of many elements have a neurotoxic effect. Intoxication can lead to acute and chronic pathologies and cause life-threatening complications.

The negative consequences of soil pollution include the following:

• violation of cultural development;
• decrease in overall soil fertility;
• death of useful plants;
• decrease in water quality;
• decrease in the amount of nutrients in the soil structure;
• negative impact on fauna;
• effect on microbiological properties.

Soil pollution with metals provokes a violation of the cycle of substances in nature. This negatively affects all components of the biosphere.

The penetration of heavy metals into the soil is considered a side effect of human activities. To minimize the negative impact of these substances, it is necessary to accurately determine the composition of the soil and, if necessary, clean it.

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