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The consequences of human activities on the environment




In accordance with the population density, the degree of human impact on the environment is changing. However, at the current level of development of productive forces, the activity of human society affects the biosphere as a whole. Humanity with its social laws of development and powerful technology is quite capable of influencing the secular course of biospheric processes.

Air pollution.

In the process of his activity, man pollutes the air. Over cities and industrial areas, the concentration of gases in the atmosphere increases, which in rural areas are contained in very small quantities or are completely absent. Polluted air is harmful to health. In addition, harmful gases, combined with atmospheric moisture and falling in the form of acid rain, degrade the quality of the soil and reduce the yield.

The main causes of air pollution are the burning of fossil fuels and metallurgical production. If in the 19th century the products of the combustion of coal and liquid fuels entering the environment were almost completely assimilated by the vegetation of the Earth, then at present the content of harmful products of combustion is steadily increasing. A whole series of pollutants enters the air from the stoves, furnaces, exhaust pipes of automobiles. Among them, sulfur dioxide is particularly prominent - a poisonous gas that is readily soluble in water.

The concentration of sulfur dioxide in the atmosphere is especially high in the vicinity of smelters. It causes the destruction of chlorophyll , the underdevelopment of pollen grains, the drying of the falling leaves of needles. Part of SO 2 is oxidized to sulfuric anhydride. Sulfuric and sulfuric acid solutions, falling with rains on the Earth's surface, cause harm to living organisms, destroy buildings. The soil acquires an acid reaction, humus (humus) is washed out of it - an organic substance containing the components necessary for the development of plants. In addition, it reduces the amount of salts of calcium, magnesium, potassium. In acidic soils, the number of animal species living in it decreases, and the rate of decay decomposition is slowed down. All this creates unfavorable conditions for plant growth.

Each year, as a result of fuel combustion, billions tons of CO 2 are released into the atmosphere. Half of the carbon dioxide produced by the combustion of fossil fuels is absorbed by the ocean and green plants, half remains in the air. The atmospheric CO 2 content is gradually increasing and over the past 100 years has increased by more than 10%. CO 2 inhibits thermal radiation into outer space, creating the so-called “greenhouse effect”. Changes in CO 2 in the atmosphere significantly affect the Earth’s climate.


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Industrial enterprises and automobiles cause the release of many toxic compounds into the atmosphere - nitric oxide, carbon monoxide, lead compounds (each car emits 1 kg of lead per year), various hydrocarbons - acetylene, ethylene, methane, propane, etc. Together with water droplets they form a poisonous fog - smog that has a harmful effect on the human body, on the vegetation of cities. Liquid and solid particles (dust) suspended in the air reduce the amount of solar radiation reaching the Earth's surface. So, in large cities, solar radiation is reduced by 15%, ultraviolet radiation - by 30% (and in the winter months it can completely disappear).

Freshwater pollution.

Water use is increasing rapidly. This is due to population growth and improving the sanitary and hygienic conditions of human life, the development of industry and irrigated agriculture. The daily water consumption for household needs in rural areas is 50 liters per person, in cities - 150 liters.

A huge amount of water is used in industry. For the smelting of 1 ton of steel, 200 m 3 of water is required, and for the production of 1 ton of synthetic fiber, from 2500 to 5000 m 3 . Industry absorbs 85% of all urban water.

Even more water is needed for irrigation. During the year, 12-14 m 3 of water is consumed per 1 ha of irrigated land. In our country, more than 150 km 3 is spent annually on irrigation.

A constant increase in water consumption on the planet leads to the danger of “water hunger”, which necessitates the development of measures for the rational use of water resources. In addition to a high level of discharge, water shortage is caused by its growing pollution due to the discharge of industrial and especially chemical waste into rivers. Bacterial contamination and toxic chemicals (such as phenol ) lead to necrosis of water bodies. The mole alloy of the forest along the rivers, which is often accompanied by congestion, also has harmful consequences. If the wood stays in the water for a long time, it loses its business qualities, and the substances washed out of it have a detrimental effect on fish.



Mineral fertilizers, nitrates and phosphates, which are washed out from the soil by rain and enter the rivers and lakes, can in large concentrations dramatically change the species composition of water bodies, as well as various pesticides - pesticides used in agriculture to control pests. For aerobic organisms living in fresh waters, the discharge of warm water by enterprises is also an adverse factor. Oxygen is poorly soluble in warm water and its deficiency can lead to many deaths.

Pollution of the oceans. Significant pollution are the waters of the seas and oceans. Pathogenic waste, oil products, salts of heavy metals, toxic organic compounds, including pesticides, come into the sea with river runoff, as well as from sea transport. Pollution of the seas and oceans reaches such proportions that in some cases the caught fish and mollusks turn out to be unsuitable for eating.

Anthropogenic changes in the soil.

The fertile soil layer forms for a very long time. At the same time, tens of millions of tons of nitrogen, potassium, phosphorus, the main components of plant nutrition, are removed from the soil every year along with the crop. Humus, the main factor in soil fertility, is found in chernozems in an amount of less than 5% of the mass of the arable layer. On poor soils, humus is even less. In the absence of replenishment of soils with nitrogen compounds, its reserve can be used up in 50-100 years. This does not happen, since cultural agriculture provides for the introduction of organic and inorganic (mineral) fertilizers into the soil.

Nitrogen fertilizers introduced into the soil are used by plants by 40-50%. The rest is reduced by microorganisms to gaseous substances, escapes into the atmosphere or leaches from the soil. Thus, mineral nitrogen fertilizers are quickly consumed, so they have to be applied annually. With insufficient use of organic and inorganic fertilizers, the soil is depleted and yields fall. Adverse changes in the soil also occur as a result of improper crop rotation, i.e., the annual sowing of the same crops, such as potatoes.

Anthropogenic soil changes include erosion (erosion). Erosion is the destruction and demolition of soil cover by water currents or wind. Widespread and most destructive is water erosion. It occurs on the slopes and develops with improper cultivation of the land. Together with melt and rainwater from the fields, millions of tons of soil are annually carried into rivers and seas. If nothing prevents the erosion, small ravines turn into deeper and, finally, into ravines.

Wind erosion occurs in areas with dry exposed soil, with sparse vegetation. Excessive grazing in the steppes and semi-deserts contributes to wind erosion and the rapid destruction of grass cover. It takes 250-300 years to restore a soil layer 1 cm thick under natural conditions. Consequently, dust storms bring irreparable losses to the fertile soil layer.

Significant areas with formed soils are withdrawn from agricultural circulation due to the open method of developing minerals occurring at shallow depths. An open-pit mining method is cheap, as it eliminates the construction of expensive mines and a complex communications system, and is also safer. Dug deep quarries and dumps of soil destroy not only the lands to be developed, but also the surrounding territories, while the hydrological regime of the area is violated, water, soil and atmosphere are polluted, and crop yields are reduced.

Human influence on flora and fauna.

Human impacts on wildlife consist of direct influence and indirect changes in the natural environment. One form of direct impact on plants and animals is logging. Selective and sanitary cuttings that regulate the composition and quality of the forest and are necessary to remove damaged and diseased trees do not significantly affect the species composition of forest biocenoses.

Another thing is the clear cutting of the stand. Finding themselves suddenly in an open habitat, plants of the lower tiers of the forest are adversely affected by direct solar radiation. In shade-loving plants of grassy and shrub tiers, chlorophyll is destroyed, growth is inhibited, some species disappear. Light-loving plants that are resistant to elevated temperature and lack of moisture settle in the place of felling. The fauna is also changing: species associated with forest stand disappear or migrate to other places.

A significant impact on the state of the vegetation cover is exerted by a massive visit to the forests by vacationers and tourists. In these cases, the harmful effect is trampling, soil compaction and soil contamination. The direct influence of man on the animal kingdom consists in the extermination of species representing for him food or other material benefits. It is believed that since 1600, more than 160 species and subspecies of birds and at least 100 species of mammals have been exterminated by humans. The long list of extinct species includes a tour - a wild bull that lived throughout Europe.

In the XVIII century. G.V. described by the Russian naturalist was exterminated Steller's sea ​​cow (Steller's cow) is an aquatic mammal belonging to the order of sirens. A little over a hundred years ago, the wild tarpan horse that lived in southern Russia disappeared. Many species of animals are on the verge of extinction or preserved only in reserves. Such is the fate of the bison, tens of millions inhabiting the prairies of North America, and bison, formerly widespread in the forests of Europe. In the Far East, sika deer are almost completely exterminated. Intensive fishing of cetaceans brought several species of whales to the brink of destruction: gray, greenland, blue.

The number of animals is also influenced by human activities not related to fishing. The number of the Ussuri tiger has sharply decreased. This happened as a result of the development of territories within its range and a decrease in food supply. In the Pacific Ocean, several tens of thousands of dolphins die every year: during fishing, they fall into the net and cannot get out of them. Until recently, before fishermen took special measures, the number of dolphins dying in nets reached hundreds of thousands.

For marine mammals, the effects of water pollution are very unfavorable. In such cases, the prohibition of trapping animals is ineffective. For example, after the ban on catching dolphins in the Black Sea, their numbers are not restored. The reason is that many toxic substances enter the Black Sea with river water and through straits from the Mediterranean Sea. These substances are especially harmful to dolphin cubs, whose high mortality prevents the growth of the population of these cetaceans.

The extinction of a relatively small number of species of animals and plants may not seem very significant. Each species occupies a specific place in the biocenosis , in the chain and no one can replace it. The disappearance of a species leads to a decrease in the stability of biocenoses. More importantly, each species has unique properties unique to it. The loss of genes that determine these properties and were selected during a long evolution, deprives a person of the opportunity in the future to use them for their practical purposes (for example, for selection).

Radioactive pollution of the biosphere.

The problem of radioactive contamination arose in 1945 after the explosion of atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki. Tests of nuclear weapons carried out before 1963 in the atmosphere caused global radioactive contamination. In the explosion of atomic bombs, very strong ionizing radiation occurs, radioactive particles disperse over long distances, infecting the soil, water bodies, living organisms. Many radioactive isotopes have a long half-life, remaining dangerous throughout their life. All these isotopes are included in the cycle of substances, get into living organisms and have a detrimental effect on cells.

Tests of nuclear weapons (and even more so when using these weapons for military purposes) have another negative side. A nuclear explosion produces an enormous amount of fine dust, which is held in the atmosphere and absorbs a significant part of solar radiation. Calculations by scientists from different countries of the world show that even with limited, local use of nuclear weapons, the resulting dust will retain most of the solar radiation. There will come a long cold snap (“nuclear winter”), which will inevitably lead to the death of all life on Earth.

Currently, almost any territory of the planet from the Arctic to Antarctica is subject to a variety of anthropogenic influences. The consequences of the destruction of natural biocenoses and environmental pollution have become very serious. The whole biosphere is under ever-increasing pressure of human activity, therefore, environmental protection measures become an urgent task.

Acid atmospheric attacks on land.

One of the most acute global problems of the present and the foreseeable future is the problem of increasing acidity of precipitation and soil cover. Areas of acidic soils do not know droughts, but their natural fertility is lowered and unstable; they are rapidly depleted and their yields are low. Acid rains cause not only acidification of surface waters and upper horizons of soils. Acidity with downward flows of water extends to the entire soil profile and causes significant groundwater acidification.

Acid rain occurs as a result of human activities, accompanied by the emission of colossal amounts of oxides of sulfur, nitrogen, carbon. These oxides, entering the atmosphere, are transported over long distances, interact with water and turn into solutions of a mixture of sulfuric, sulfuric, nitrous, nitric and carbonic acids, which fall in the form of "acid rains" on land, interacting with plants, soils, and waters. The main sources in the atmosphere are the burning of oil shale, oil, coal, gas in industry, in agriculture, in everyday life.

Human economic activity almost doubled the release of sulfur, nitrogen, hydrogen sulfide and carbon monoxide into the atmosphere. Naturally, this affected the increase in the acidity of precipitation, ground and groundwater. To solve this problem, it is necessary to increase the volume of systematic representative measurements of compounds of air polluting substances in large areas.





; Date Added: 2014-02-02 ; ; views: 45564 ; Does published material infringe copyright? | | Personal Data Protection | ORDER JOB


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