Thermal pollution refers to phenomena in which heat is released into water bodies or into atmospheric air. In this case, the temperature rises much higher than the average norm. Thermal pollution of nature is associated with human activities and greenhouse gas emissions, which are the main cause of global warming.
Sources of thermal pollution of the atmosphere
Two groups of sources are distinguished:
- natural - these are forest fires, volcanoes, dust storms, dry winds, the decomposition of living and plant organisms;
- Anthropogenic ones are oil and gas processing, industrial activity, heat power engineering, nuclear power engineering, transport.
About 25 billion tons of carbon monoxide, 190 million tons of sulfur oxide, 60 million tons of nitric oxide enter the Earth’s atmosphere annually as a result of human activity. Half of all this waste is added as a result of the activities of the energy industry, industry and metallurgy.
In recent years, the amount of exhaust gases from cars has increased.
Effects
In megacities with large industrial enterprises, atmospheric air experiences severe thermal pollution. It receives substances that have a higher temperature than the air layer of the surrounding surface. The temperature of industrial emissions is always above the average surface air layer. For example, during forest fires, from the exhaust pipes of automobiles, from pipes of industrial enterprises, when heating houses, streams of warm air with various impurities are released. The temperature of such a stream is about 50-60 º. This layer increases the average annual temperature in the city by six to seven degrees. In the cities and above them "islands of heat" are formed, which leads to an increase in cloudiness, while the amount of precipitation increases and the humidity of the air increases. When combustion products are attached to the humid air, a wet smog is formed (London type). Environmentalists say that over the past 20 years, the average temperature of the troposphere has increased by 0.7º C.
Sources of thermal soil pollution
Sources of thermal pollution of soils in large cities and industrial centers are:
- gas pipes of metallurgical enterprises, the temperature reaches 140-150º;
- heating mains, temperature about 60-160º;
- communication bends, temperature 40-50º .
Consequences of thermal effects on soil cover
Gas pipes, heating mains and communication bends increase the temperature of the soil by several degrees, which negatively affects the soil. In winter, this leads to snow melting and, as a result, freezing of the surface soil layers, and in summer, the reverse process occurs, the upper soil layer is heated and dried out. The soil cover is closely related to the vegetation and living microorganisms that live in it. A change in its composition negatively affects their livelihoods.
Sources of thermal pollution of hydrological objects
Thermal pollution of water bodies and coastal marine areas occurs as a result of the discharge of wastewater into water bodies by nuclear and thermal power plants, and industrial enterprises.
Effects of wastewater discharges
The discharge of wastewater leads to an increase in water temperature in water bodies by 6-7 º, the area of such warm spots can reach up to 30-40 km 2 .
Warm layers of water form a kind of film on the surface of the water mass, which prevents natural water exchange (surface water does not mix with bottom water ), the amount of oxygen decreases, and the need for organisms in it increases, while the species quantity of algae increases.
The greatest degree of thermal pollution of water is carried out by power plants. Water is used to cool turbines of nuclear power plants and gas condensate in thermal power plants. Water used by power plants is heated by about 7-8 º, after which it is discharged into nearby water bodies.
An increase in water temperature in water bodies negatively affects living organisms. For each of them there is a temperature optimum at which the population feels excellent. In the natural environment, with a slow increase or decrease in temperature, living organisms gradually adapt to changes, but if the temperature rises sharply (for example, with a large volume of runoff by industrial enterprises), then the organisms do not have time for acclimatization. They receive heat shock, which may result in death. This is one of the most negative effects of thermal pollution on aquatic organisms.
But there may be other, more harmful consequences. For example, the effect of thermal pollution of water on metabolism. With an increase in temperature, organisms increase the metabolic rate, and the need for oxygen increases. But with increasing water temperature, the oxygen content in it decreases. Its lack leads to the death of many species of aquatic living organisms. Almost 100% destruction of fish and invertebrates causes an increase in water temperature by several degrees in the summer. When the temperature regime changes, the behavior of the fish also changes, natural migration is disturbed, and untimely spawning occurs.
Thus, an increase in water temperature can change the species structure of water bodies. Many species of fish either leave these territories or die. Algae characteristic of these places are replaced by thermophilic species.
If, together with warm water, organic and mineral substances (household effluents, mineral fertilizers washed out from the fields) fall into the water bodies, algae multiply sharply, they begin to form a dense mass, closing each other. As a result of this, their death and decay occurs, which leads to the pestilence of all living organisms of the reservoir.
Thermal pollution of water bodies by thermal power plants is dangerous . They generate energy with the help of turbines, the exhaust gas must be cooled from time to time. Used water is discharged into water bodies. At large thermal power plants, this amount reaches 90 m 3 . This means that a continuous warm stream enters the reservoir.
Damage from pollution of aquatic ecosystems
All the consequences of thermal pollution of water bodies cause catastrophic harm to living organisms and change the human environment. As a result of pollution, damage is caused:
- aesthetic (the appearance of landscapes is violated);
- economic (elimination of the consequences of pollution, the extinction of many species of fish);
- ecological (species of aquatic vegetation and living organisms are destroyed).
Volumes of warm water discharged by power plants are constantly growing, therefore, the temperature of water bodies will also increase. In many rivers, according to ecologists, it will increase by 3-4 ° . This process is already underway. For example, in some rivers of America, overheating of water is about 10-15 ° C, England - 7-10 ° C, France - 5 ° C.
Thermal pollution
Thermal pollution (thermal physical pollution) is a form that occurs as a result of an increase in ambient temperature. Its causes are industrial and military emissions of heated air, large fires.
Thermal pollution of the environment is associated with the work of enterprises of the chemical, pulp and paper, metallurgy, woodworking industries, thermal power plants and nuclear power plants, which require large volumes of water to cool equipment.
A powerful polluter is transport. About 80% of all annual emissions are cars. Many harmful substances disperse over considerable distances from the source of pollution.
When burning gas at thermal power plants, in addition to chemical effects on the atmosphere, thermal pollution also occurs. In addition, approximately 4 km from the torch, many plants are in a depressed state, and a vegetation cover dies within a radius of 100 meters.
About 80 million tons of various industrial and household waste are generated annually on the territory of Russia, which are a source of pollution of soil cover, vegetation, ground and surface waters, and atmospheric air. In addition, they are a source of radiation and thermal pollution of natural objects.
Land waters are contaminated with a variety of chemical wastes that get there when the mineral fertilizers, pesticides from the soils, with sewage and industrial effluents are washed away. Thermal and bacterial pollution occurs in water bodies, many species of plants and animals die.
Any discharge of heat into the natural environment leads to a change in the temperature of its components; the lower layers of the atmosphere, soil and hydrosphere objects experience a particularly strong influence.
According to environmentalists, thermal emissions into the environment are not yet able to affect the balance of the planet, but they have a significant effect on a specific territory. For example, the air temperature in large cities is usually slightly higher than outside the city; the thermal regime of rivers or lakes changes when sewage from thermal power plants is discharged. The species composition of the inhabitants of these spaces is changing. Each species has its own temperature range at which the species is able to adapt. For example, trout is able to survive in warm water, but is not able to breed.
Thus, thermal discharges also affect the biosphere, although it is not on a planetary scale, but it is also noticeable for humans.
Temperature pollution of the soil cover is fraught with the fact that there is a close interaction with animals, vegetation and microbial organisms. When the temperature of the soil increases, the vegetation changes to more thermophilic species, many microorganisms die, unable to adapt to new conditions.
Groundwater thermal pollution occurs as a result of runoff entering aquifers. This negatively affects the quality of water, its chemical composition, and thermal conditions.
Thermal pollution of the environment worsens the living conditions and human activities. In cities at elevated temperatures in combination with high humidity, people experience frequent headaches, general malaise, and jumps in blood pressure. High humidity leads to corrosion of metals, damage to sewers, heat pipes, gas pipes and so much more.
The consequences of environmental pollution
You can specify all the consequences of thermal pollution of the environment and highlight the main problems that need to be addressed:
1. Thermal islands are formed in large cities.
2. Smog forms, air humidity increases and constant cloudiness forms in megacities.
3. There are problems in rivers, lakes and coastal waters of the seas and oceans. Due to the increase in temperature, the ecological balance is disturbed, many species of fish and aquatic plants die.
4. The chemical and physical properties of water are changing. It becomes unusable even after cleaning.
5. Living organisms of water bodies die or are in a depressed state.
6. The temperature of groundwater is increasing.
7. The structure of the soil and its composition are violated, oppression or destruction of the vegetation and microorganisms living in it occurs.
Thermal pollution. Prevention and measures to prevent it
The main measure to prevent thermal pollution of the environment is the gradual abandonment of the use of fuel, a complete transition to alternative renewable energy: solar, wind and hydro energy.
To protect water areas from thermal pollution in the turbine cooling system, it is necessary to construct reservoirs - coolers, from which water after cooling can again be used in the cooling system.
In recent decades, engineers have sought to eliminate a steam turbine in thermal power plants using the magnetohydrodynamic method of converting thermal energy into electrical energy. This significantly reduces the thermal pollution of the surrounding area and water bodies.
Biologists seek to identify the limits of stability of the biosphere as a whole and of individual species of living organisms, as well as the limits of equilibrium of biological systems.
Environmentalists, in turn, are studying the degree of influence of human activities on natural processes in the environment and are trying to find ways to prevent negative effects.
Protecting the environment from thermal pollution
It is customary to separate thermal pollution into planetary and local. On a planetary scale, pollution is not very large and amounts to only 0.018% of the solar radiation entering the planet, that is, within one percent. But, thermal pollution has a strong effect on nature at a local level. To regulate this influence in most industrialized countries, limits (limits) of thermal pollution have been introduced.
As a rule, the limit is set for the regime of water bodies, since it is the seas, lakes and rivers that suffer to a large extent from thermal pollution and take its main part.
In Europe, water bodies should not be warmed more than 3 ° C from their natural temperature.
In the United States, water heating in rivers should not be whiter than 3 ° C, in lakes - 1.6 ° C, in the waters of the seas and oceans - 0.8 ° C.
In Russia, the temperature of water in reservoirs should not increase by more than 3 ° C compared with the average temperature of the hottest month. In reservoirs inhabited by salmon and other cold-loving species of fish, the temperature cannot be increased by more than 5 ° C, in summer no higher than 20 ° C, in winter - 5 ° C.
The scale of thermal pollution near large industrial centers is quite significant. So, for example, from an industrial center with a population of 2 million people, with a nuclear power plant and an oil refinery, thermal pollution spreads to a distance of 120 km and 1 km in height.
Environmentalists suggest using thermal waste for household needs, for example:
- for irrigation of agricultural land;
- in a greenhouse;
- to maintain the northern waters free from ice;
- the distillation of heavy products of the oil industry and fuel oil;
- for breeding heat-loving species of fish;
- for the construction of artificial ponds heated in winter, for wild waterfowl.
On a planetary scale, thermal pollution of the environment indirectly affects global warming. GHG emissions by industrial enterprises do not directly affect the temperature increase, but lead to its increase as a result of the greenhouse effect.
To solve environmental problems and prevent them in the future, mankind must solve a number of global problems and direct all efforts to reduce air pollution, thermal pollution of the planet.