Where does polluted water enter the river? The dirtiest rivers in the world
Water is the most valuable natural resource. Its role is participation in the process of metabolism of all substances that are the basis of any life form. It is impossible to imagine the activity of industrial, agricultural enterprises without the use of water, it is indispensable in human everyday life. Everyone needs water: people, animals, plants. For some, it is a habitat.
The rapid development of human life, the inefficient use of resources has led to the fact that e environmental problems (including water pollution) have become too acute. Their solution is in the first place for humanity. Scientists, environmentalists around the world are sounding the alarm and trying to find a solution to the world problem
Sources of water pollution
There are many reasons for pollution, and not always the human factor is to blame. Natural disasters also harm clean water bodies and disrupt the ecological balance.
The most common sources of water pollution are:
nuclear weapons testing;
dumping of radioactive waste;
major accidents (ships with nuclear reactors, Chernobyl);
burial at the bottom of the oceans, seas of radioactive waste.
Industrial, domestic waste water. Having not passed the system of purification from chemical harmful substances, they, getting into the reservoir, provoke an ecological catastrophe.
Tertiary cleaning. Water is treated with powders, special compounds, filtered in many stages, killing harmful organisms and destroying other substances. It is used for domestic needs of citizens, as well as in the food industry, in agriculture.
- radioactive contamination of water
The main sources that pollute the oceans include the following radioactive factors:
Environmental problems and water pollution are directly related to radioactive waste contamination. For example, French and British nuclear plants have infected almost the entire North Atlantic. Our country has become the culprit of the pollution of the Arctic Ocean. Three nuclear underground reactors, as well as the production of Krasnoyarsk-26, clogged the largest river, the Yenisei. It is obvious that radioactive products got into the ocean.
Pollution of world waters with radionuclides
The problem of pollution of the waters of the oceans is acute. Let us briefly list the most dangerous radionuclides that fall into it: cesium-137; cerium-144; strontium-90; niobium-95; yttrium-91. All of them have a high bioaccumulative capacity, move along food chains and concentrate in marine organisms. This creates a danger for both humans and aquatic organisms.
The water areas of the Arctic seas are heavily polluted by various sources of radionuclides. People carelessly dump hazardous waste into the ocean, thereby turning it into a dead one. Man must have forgotten that the ocean is the main wealth of the earth. It has powerful biological and mineral resources. And if we want to survive, we must urgently take measures to save him.
Solutions
Rational consumption of water, protection from pollution are the main tasks of mankind. Ways to solve environmental problems of water pollution lead to the fact that, first of all, much attention should be paid to the discharge of hazardous substances into rivers. On an industrial scale, it is necessary to improve wastewater treatment technologies. In Russia, it is necessary to introduce a law that would increase the collection of fees for discharges. The proceeds should be directed to the development and construction of new environmental technologies. For the smallest emissions, the fee should be reduced, this will serve as a motivation for maintaining a healthy environmental situation.
An important role in solving environmental problems is played by the upbringing of the younger generation. From an early age, it is necessary to teach children to respect, love for nature. To inspire them that the Earth is our big house, for the order in which each person is responsible. Water must be protected, not poured thoughtlessly, try to prevent foreign objects and harmful substances from getting into the sewer.
Conclusion
In conclusion, I would like to say that Russian environmental problems and water pollution concern, perhaps, everyone. The thoughtless waste of water resources, the littering of rivers with various garbage has led to the fact that there are very few clean, safe corners left in nature.Ecologists have become much more vigilant, multiple measures are being taken to restore order in the environment. If each of us thinks about the consequences of our barbaric, consumer attitude, the situation can be corrected. Only together will humanity be able to save water bodies, the World Ocean and, possibly, the lives of future generations.
WATER POLLUTION
changes in the chemical and physical state or biological characteristics of water, limiting its further use. With all types of water use, either the physical state (for example, when heated) or the chemical composition of water change when pollutants enter, which are divided into two main groups: those that change over time in the aquatic environment and remain unchanged in it. The first group includes organic components of domestic wastewater and most industrial waste, such as waste from pulp and paper mills. The second group consists of many inorganic salts, such as sodium sulfate, which is used as a dye in the textile industry, and inactive organic substances such as pesticides.
SOURCES OF POLLUTION
Settlements. The most well-known source of water pollution, which has traditionally been the focus of attention, is domestic (or municipal) wastewater. Urban water consumption is usually estimated based on the average daily water consumption per person, which in the United States is approximately 750 liters and includes drinking water, for cooking and personal hygiene, for the operation of household plumbing devices, as well as for watering lawns and lawns, extinguishing fires, washing streets and other urban needs. Almost all used water goes to the sewer. Since a huge volume of feces enters wastewater every day, the main task of municipal services in the processing of domestic wastewater in sewage treatment plants is to remove pathogens. When insufficiently treated fecal effluents are reused, the bacteria and viruses they contain can cause intestinal diseases (typhoid, cholera and dysentery), as well as hepatitis and poliomyelitis. Soap, synthetic washing powders, disinfectants, bleaches and other household chemicals are present in dissolved form in wastewater. Residential buildings receive paper waste, including toilet paper and baby diapers, plant and animal waste. Rain and melt water flows from the streets into sewers, often with sand or salt used to accelerate the melting of snow and ice on the roadway and sidewalks.
Industry. In industrialized countries, industry is the main consumer of water and the largest source of wastewater. Industrial effluents into rivers are 3 times higher than domestic ones. Water performs various functions, for example, it serves as a raw material, a heater and a cooler in technological processes, in addition, it transports, sorts and rinses various materials. Water also removes waste at all stages of production - from the extraction of raw materials, the preparation of semi-finished products to the release of final products and their packaging. Since it is much cheaper to dispose of waste from different production cycles than to process and dispose of, a huge amount of various organic and inorganic substances is discharged with industrial effluents. More than half of the effluents entering water bodies come from four main industries: pulp and paper, oil refining, organic synthesis, and ferrous metallurgy (blast furnace and steel production). Due to the growing volume of industrial waste, the ecological balance of many lakes and rivers is disturbed, although most of the effluent is non-toxic and non-lethal to humans.
Thermal pollution. The largest single use of water is in electricity generation, where it is used primarily to cool and condense the steam generated by the turbines of thermal power plants. At the same time, water is heated by an average of 7 ° C, after which it is discharged directly into rivers and lakes, being the main source of additional heat, which is called "thermal pollution". There are objections to the use of this term, since an increase in water temperature sometimes leads to favorable environmental consequences.
Agriculture. The second main consumer of water is agriculture, which uses it to irrigate fields. The water flowing from them is saturated with salt solutions and soil particles, as well as chemical residues that contribute to increased yields. These include insecticides; fungicides that are sprayed over orchards and crops; herbicides, a famous weed control; and other pesticides, as well as organic and inorganic fertilizers containing nitrogen, phosphorus, potassium and other chemical elements. In addition to chemical compounds, a large amount of faeces and other organic residues from farms where meat and dairy cattle, pigs or poultry are raised enter the rivers. A lot of organic waste also comes from the processing of agricultural products (when cutting meat carcasses, processing leather, producing foodstuffs and canned food, etc.).
IMPACT OF POLLUTION
Pure water is transparent, colorless, odorless and tasteless, inhabited by many fish, plants and animals. Polluted waters are cloudy, foul-smelling, unsuitable for drinking, and often contain large amounts of bacteria and algae. The water self-purification system (aeration with running water and sedimentation of suspended particles on the bottom) does not work due to an excess of anthropogenic pollutants in it.
Decreased oxygen content. The organic matter contained in the wastewater is decomposed by the enzymes of aerobic bacteria, which absorb the oxygen dissolved in the water and release carbon dioxide as the organic residues are assimilated. Common end products of decomposition are carbon dioxide and water, but many other compounds can be formed. For example, bacteria process the nitrogen contained in the waste into ammonia (NH3), which, when combined with sodium, potassium or other chemical elements, forms salts of nitric acid - nitrates. Sulfur is converted into hydrogen sulfide compounds (substances containing the radical -SH or hydrogen sulfide H2S), which gradually turn into sulfur (S) or sulfate ion (SO4-), which also forms salts. In waters containing faecal masses, plant or animal residues coming from the food industry, paper fibers and cellulose residues from the pulp and paper industry, the decomposition processes proceed in almost the same way. Since aerobic bacteria use oxygen, the first result of the decomposition of organic residues is a decrease in the oxygen content dissolved in the receiving waters. It varies with temperature, and to some extent with salinity and pressure. Fresh water at 20°C and intensive aeration in one liter contains 9.2 mg of dissolved oxygen. As the water temperature rises, this indicator decreases, and when it cools, it increases. According to the standards in force for the design of municipal wastewater treatment plants, the decomposition of organic substances contained in one liter of municipal wastewater of normal composition at a temperature of 20 ° C requires approximately 200 mg of oxygen for 5 days. This value, called Biochemical Oxygen Demand (BOD), is taken as the standard for calculating the amount of oxygen needed to treat a given amount of wastewater. The value of BOD of wastewater from enterprises of the leather, meat processing and sugar refinery industries is much higher than that of municipal wastewater. In shallow streams with a fast current, where water is intensively mixed, oxygen coming from the atmosphere compensates for the depletion of its reserves dissolved in water. At the same time, carbon dioxide, which is formed during the decomposition of substances contained in wastewater, escapes into the atmosphere. Thus, the period of adverse effects of organic decomposition processes is reduced. Conversely, in low-flowing water bodies, where the waters mix slowly and are isolated from the atmosphere, the inevitable decrease in oxygen content and an increase in carbon dioxide concentration entail serious changes. When the oxygen content decreases to a certain level, fish die and other living organisms begin to die, which, in turn, leads to an increase in the volume of decaying organic matter. Most of the fish die due to poisoning by industrial and agricultural effluents, but many also die from a lack of oxygen in the water. Fish, like all living things, take in oxygen and release carbon dioxide. If there is little oxygen in the water, but a high concentration of carbon dioxide, the intensity of their respiration decreases (it is known that water with a high content of carbonic acid, i.e. carbon dioxide dissolved in it, becomes acidic).
[s]tbl_dirt.jpg. TYPICAL WATER POLLUTANTS IN SOME INDUSTRIES
In waters experiencing thermal pollution, conditions are often created that lead to the death of fish. There, the oxygen content decreases, since it is slightly soluble in warm water, but the demand for oxygen increases sharply, since the rate of its consumption by aerobic bacteria and fish increases. The addition of acids, such as sulfuric acid, to drainage water from coal mines also greatly reduces the ability of some fish to extract oxygen from the water. Biodegradability. Man-made materials that biodegrade increase the burden on bacteria, which in turn increases the consumption of dissolved oxygen. These materials are specially created in such a way that they can be easily processed by bacteria, i.e. decompose. Natural organic matter is usually biodegradable. In order for artificial materials to have this property, the chemical composition of many of them (for example, detergents and cleaning products, paper products, etc.) was changed accordingly. The first synthetic detergents were resistant to biodegradation. When huge suds began to accumulate at municipal wastewater treatment plants and disrupt the operation of some water treatment plants due to saturation with pathogens or floated down rivers, this circumstance was brought to public attention. Detergent manufacturers have solved the problem by making their products biodegradable. But this decision also provoked negative consequences, since it led to an increase in the BOD of watercourses that receive wastewater, and, consequently, an acceleration in the rate of oxygen consumption.
Gas formation. Ammonia is the main product of the microbiological degradation of proteins and animal excretions. Ammonia and its gaseous amine derivatives are formed both in the presence and in the absence of oxygen dissolved in water. In the first case, ammonia is oxidized by bacteria to form nitrates and nitrites. In the absence of oxygen, ammonia does not oxidize and its content in water remains stable. When the oxygen content decreases, the formed nitrites and nitrates turn into gaseous nitrogen. This happens quite often when water flowing from fertilized fields and already containing nitrates enters stagnant water bodies, where organic residues also accumulate. The bottom silts of such water bodies are inhabited by anaerobic bacteria that develop in an anoxic environment. They use the oxygen present in sulfates and form hydrogen sulfide. When there is not enough available oxygen in the compounds, other forms of anaerobic bacteria develop, which ensure the decay of organic matter. Depending on the type of bacteria, carbon dioxide (CO2), hydrogen (H2) and methane (CH4) are formed - a colorless and odorless combustible gas, which is also called swamp gas. Eutrophication, or eutrophication, is the process of enrichment of water bodies with nutrients, especially nitrogen and phosphorus, mainly of biogenic origin. As a result, the lake gradually overgrows and turns into a swamp filled with silt and decaying plant remains, which eventually dries up completely. Under natural conditions, this process takes tens of thousands of years, but as a result of anthropogenic pollution, it proceeds very quickly. So, for example, in small ponds and lakes, under the influence of man, it ends in just a few decades. Eutrophication is enhanced when plant growth in a water body is stimulated by nitrogen and phosphorus found in fertilizer-laden runoff from agricultural land, cleaning and detergents, and other wastes. The waters of the lake that receives these effluents are a fertile environment in which there is a rapid growth of aquatic plants, occupying the space in which fish usually live. Algae and other plants, dying, fall to the bottom and are decomposed by aerobic bacteria that consume oxygen for this, which leads to the death of fish. The lake is filled with floating and attached algae and other aquatic plants, as well as small animals that feed on them. Blue-green algae, or cyanobacteria, make the water look like pea soup with a foul smell and fishy taste, and also cover the stones with a slimy film.
Thermal pollution. The temperature of the water used in thermal power plants to cool steam rises by 3-10 ° C, and sometimes up to 20 ° C. The density and viscosity of the heated water differ from the properties of the colder water of the receiving pool, so they mix gradually. Warm water is cooled either around the drain or in a mixed stream flowing downstream of the river. Powerful power plants noticeably heat the waters in the rivers and bays on which they are located. In summer, when the need for electrical energy for air conditioning is very high and its production increases, these waters often overheat. The concept of "thermal pollution" refers precisely to such cases, since excess heat reduces the solubility of oxygen in water, accelerates the rate of chemical reactions and, therefore, affects the life of animals and plants in water intake basins. There are vivid examples of how, as a result of an increase in water temperature, fish died, obstacles arose in the way of their migration, algae and other lower weeds multiplied rapidly, and untimely seasonal changes in the aquatic environment occurred. However, in some cases, fish catches have increased, the growing season has been extended, and other beneficial effects have been observed. Therefore, we emphasize that for a more correct use of the term "thermal pollution" it is necessary to have much more information about the effect of additional heat on the aquatic environment in each specific place.
Accumulation of toxic organic substances. The persistence and toxicity of pesticides have ensured success in the fight against insects (including malarial mosquitoes), various weeds and other pests that destroy crops. However, it has been proven that pesticides are also environmentally harmful substances, as they accumulate in different organisms and circulate within the food, or trophic, chains. The unique chemical structures of pesticides defy the usual processes of chemical and biological degradation. Therefore, when plants and other living organisms treated with pesticides are consumed by animals, poisonous substances accumulate and reach high concentrations in their bodies. As larger animals eat smaller ones, these substances move up the food chain. This happens both on land and in water. Chemicals dissolved in rainwater and absorbed by soil particles are washed out into groundwater and then into rivers that drain agricultural land, where they begin to accumulate in fish and smaller aquatic organisms. Although some living organisms have adapted to these harmful substances, there have been cases of mass death of individual species, probably due to poisoning with agricultural pesticides. For example, insecticides rotenone and DDT and pesticides 2,4-D and others have dealt a severe blow to the ichthyofauna. Even if the concentration of toxic chemicals is non-lethal, these substances can lead to animal death or other detrimental effects on the next step in the food chain. For example, gulls have died after eating large amounts of fish containing high concentrations of DDT, and several other fish-eating bird species, including the bald eagle and pelican, have been threatened with extinction due to reduced reproduction. Because of the pesticides that have entered their bodies, the eggshell becomes so thin and fragile that the eggs break and the embryos of the chicks die.
Nuclear pollution. Radioactive isotopes, or radionuclides (radioactive forms of chemical elements), also accumulate within food chains because they are persistent in nature. In the process of radioactive decay, the nuclei of atoms of radioisotopes emit elementary particles and electromagnetic radiation. This process begins simultaneously with the formation of a radioactive chemical element and continues until all its atoms are transformed under the influence of radiation into atoms of other elements. Each radioisotope is characterized by a certain half-life - the time during which the number of atoms in any of its samples is halved. Since the half-life of many radioactive isotopes is quite significant (for example, millions of years), their constant emission can eventually lead to terrible consequences for living organisms inhabiting water bodies into which liquid radioactive waste is dumped. It is known that radiation destroys the tissues of plants and animals, leads to genetic mutations, infertility, and, at sufficiently high doses, to death. The mechanism of the impact of radiation on living organisms has not yet been fully elucidated, and there are no effective ways to mitigate or prevent negative consequences. But it is known that radiation accumulates, i.e. repeated exposure to low doses may eventually have the same effect as a single high exposure.
Influence of toxic metals. Toxic metals such as mercury, arsenic, cadmium and lead also have a cumulative effect. The result of their accumulation in small doses can be the same as when receiving a single large dose. Mercury contained in industrial effluents is deposited in bottom silt in rivers and lakes. Anaerobic bacteria living in the sludge process it into toxic forms (for example, methylmercury), which can lead to serious damage to the nervous system and brain of animals and humans, as well as cause genetic mutations. Methylmercury is a volatile substance released from bottom sediments, and then, together with water, enters the body of fish and accumulates in its tissues. Although the fish do not die, a person who eats such infected fish can become poisoned and even die. Arsenic is another well-known poison that enters watercourses in dissolved form. It has been found in small but measurable amounts in detergents containing water-soluble enzymes and phosphates, and in dyes intended for coloring cosmetic tissues and toilet paper. Lead (used in the production of metal products, batteries, paints, glass, gasoline and insecticides) and cadmium (used mainly in the production of batteries) also enter the water area with industrial effluents.
Other inorganic contaminants. In water intake basins, some metals, such as iron and manganese, are oxidized either as a result of chemical or biological (under the influence of bacteria) processes. For example, rust forms on the surface of iron and its compounds. Soluble forms of these metals exist in various types of wastewater: they have been found in seepage water from mines and scrap yards, as well as from natural swamps. Salts of these metals, oxidized in water, become less soluble and form solid colored precipitates that precipitate from solutions. Therefore, the water takes on a color and becomes cloudy. So, the effluents of iron ore mines and scrap metal dumps are colored red or orange-brown due to the presence of iron oxides (rust). Such inorganic pollutants as sodium chloride and sulfate, calcium chloride, etc. (ie salts formed during the neutralization of acidic or alkaline industrial effluents) cannot be processed biologically or chemically. Although these substances themselves are not transformed, they affect the quality of the waters into which the effluent is discharged. In many cases it is undesirable to use "hard" water with a high salt content, as they form a deposit on the walls of pipes and boilers. Inorganic substances such as zinc and copper are absorbed by the silty bottom sediments of streams that receive wastewater, and then, together with these fine particles, are transported by the current. Their toxic effect is stronger in an acidic environment than in a neutral or alkaline one. In acidic wastewater from coal mines, zinc, copper and aluminum reach concentrations that are lethal to aquatic organisms. Some pollutants, while not particularly toxic on their own, turn into toxic compounds upon interaction (for example, copper in the presence of cadmium).
CONTROL AND CLEANING
Three main methods of wastewater treatment are practiced. The first has existed for a long time and is the most economical: the discharge of wastewater into large watercourses, where it is diluted with fresh running water, aerated and neutralized in a natural way. Obviously, this method does not meet modern conditions. The second method is largely based on the same natural processes as the first, and consists in the removal and reduction of solids and organic matter by mechanical, biological and chemical means. It is mainly used in municipal wastewater treatment plants, which rarely have equipment for the treatment of industrial and agricultural effluents. The third method is widely known and quite common, which consists in reducing the volume of wastewater by changing technological processes; for example, by recycling materials or using natural pest control methods instead of pesticides, etc.
Cleaning of drains. Although many industrial enterprises are now trying to clean up their wastewater or close the production cycle, and the production of pesticides and other toxic substances is prohibited, the most radical and quick solution to the problem of water pollution will be the construction of additional and more modern treatment facilities.
Primary (mechanical) cleaning. Typically, gratings or screens are installed in the path of the wastewater flow, which trap floating objects and suspended particles. The sand and other coarse inorganic particles are then deposited in sloping bottom sand traps or caught in screens. Oils and fats are removed from the surface of the water with special devices (oil traps, grease traps, etc.). For some time, wastewater is transferred to settling tanks for the sedimentation of fine particles. Free floating flocculent particles are precipitated by the addition of chemical coagulants. The sludge obtained in this way, consisting of 70% organic substances, is passed through a special reinforced concrete tank - a methane tank, in which it is processed by anaerobic bacteria. As a result, liquid and gaseous methane, carbon dioxide, as well as mineral solids are formed. In the absence of a methanetank, solid waste is buried, dumped in landfills, incinerated (resulting in air pollution) or dried and used as humus or fertilizer. Secondary treatment is carried out mainly by biological methods. Since organic matter is not removed at the first stage, aerobic bacteria are used at the next stage to decompose suspended and dissolved organic matter. The main challenge here is to bring the effluent into contact with as many bacteria as possible under conditions of good aeration, as the bacteria must be able to consume a sufficient amount of dissolved oxygen. Wastewater is passed through various filters - sand, crushed stone, gravel, expanded clay or synthetic polymers (in this case, the same effect is achieved as in the process of natural purification in a channel stream that has covered a distance of several kilometers). Bacteria form a film on the surface of the filter material and decompose wastewater organics as they pass through the filter, thus reducing BOD by more than 90%. This is the so-called. bacterial filters. A 98% reduction in BOD is achieved in aeration tanks, in which, due to the forced aeration of wastewater and its mixing with activated sludge, natural oxidation processes are accelerated. Activated sludge is formed in sedimentation tanks from particles suspended in the waste liquid, not retained during preliminary treatment and adsorbed by colloidal substances with microorganisms multiplying in them. Another method of secondary purification is long-term settling of water in special ponds or lagoons (irrigation fields or filtration fields), where algae consume carbon dioxide and release oxygen necessary for the decomposition of organic matter. In this case, BOD is reduced by 40-70%, but certain temperature conditions and sunlight are required.
Tertiary cleaning. Wastewater that has undergone primary and secondary treatment still contains dissolved substances, which make it practically unsuitable for any purpose other than irrigation. Therefore, improved cleaning methods have been developed and tested to remove the remaining contaminants. Some of these methods are used in installations that purify the drinking water of reservoirs. Slowly decomposing organic compounds such as pesticides and phosphates are removed by filtering the secondary treated wastewater through activated (powdered) charcoal, either by adding coagulants to promote the agglomeration of fine particles and settling the resulting flocs, or by treating with such reagents that provide oxidation. Dissolved inorganic substances are removed by ion exchange (dissolved ions of salts and metals); chemical precipitation (calcium and magnesium salts, which form deposits on the inner walls of boilers, tanks and pipes), softening water; change in osmotic pressure for enhanced water filtration through the membrane, which retains concentrated solutions of nutrients - nitrates, phosphates, etc.; removal of nitrogen by an air stream during the passage of effluents through an ammonia desorption column; and other methods. There are only a few enterprises in the world that can carry out complete wastewater treatment.
Three important stages of the water cycle: evaporation (A), condensation (B) and precipitation (C). If too many natural or man-made pollutants from the sources listed below are involved, the natural system cannot keep up with the treatment. 1. Radioactive particles, dust and gases come from the atmosphere along with snow falling and accumulating in the highlands. 2. Glacial melt waters with dissolved pollutants flow down from the highlands, forming the headwaters of rivers, which, on their way to the sea, entrain soil and rock particles, eroding the surfaces on which they flow. 3. Waters draining mine workings contain acids and other inorganic substances. 4. Deforestation promotes erosion. Many pollutants are released into the rivers by the pulp and paper industries that process wood. 5. Rainwater leaches chemicals from the soil and decaying plants, transports them to groundwater, and also flushes soil particles from slopes into rivers. 6. Industrial gases enter the atmosphere, and from there, together with rain or snow, onto the ground. Industrial waste flows directly into the rivers. Depending on the industry, the composition of gases and wastewater varies greatly. 7. Organic insecticides, fungicides, herbicides and fertilizers dissolved in waters that drain agricultural land enter rivers. 8. Dusting fields with pesticides pollutes the air and water environment. 9. Cow dung and other residues of animal origin are the main pollutants in places of large concentrations of animals in pastures and cattle yards. 10. When fresh groundwater is pumped out, salinization may occur as a result of pulling mineralized water from estuaries and marine basins to their surface. 11. Methane is produced by bacteria both in natural swamps and in stagnant water bodies with an excess of organic pollutants of anthropogenic origin. 12. Thermal pollution of rivers occurs due to the flow of heated water from power plants. 13. Cities are sources of various wastes, including both organic and inorganic. 14. Exhaust gases of internal combustion engines are the main sources of air pollution. Hydrocarbons are adsorbed by moisture in the air. 15. Large objects and particles are removed from municipal wastewater at pre-treatment stations, organics - at secondary treatment stations. It is impossible to get rid of many substances coming with industrial effluents. 16. Oil spills from offshore oil wells and from tankers pollute waters and beaches.
Ecological dictionary
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water pollution- vandens tarša statusas T sritis ekologija ir aplinkotyra apibrėžtis Kenksmingųjų medžiagų (buitinių ir pramoninių nutekamųjų vandenų, žemės ūkio atliekų, transporto išmetamųjų dujų, naftos ir jos produktų, radioaktyviųjų medžiagų, trąšų,… … Ekologijos terminų aiskinamasis žodynas
In most cases, freshwater pollution remains invisible because the contaminants are dissolved in the water. But there are exceptions: foaming detergents, as well as oil products floating on the surface and untreated sewage. There are several ... ... Wikipedia
Water pollution of reservoirs and streams- The process of changing the composition and properties of water in reservoirs and streams under the influence of pollutants entering the water, microorganisms, heat, leading to a deterioration in water quality.
The presence of fresh clean water is a necessary condition for the existence of all living organisms on the planet.
The share of fresh water suitable for consumption accounts for only 3% of its total amount.
Despite this, a person in the process of his activity mercilessly pollutes it.
Thus, a very large volume of fresh water has now become completely unusable. A sharp deterioration in the quality of fresh water occurred as a result of contamination with chemical and radioactive substances, pesticides, synthetic fertilizers and sewage, and this is already.
Types of pollution
It is clear that all types of pollution that exist are also present in the aquatic environment.
This is quite an extensive list.
In many ways, the solution to the problem of pollution will be .
heavy metals
During the operation of large factories, industrial effluents are discharged into fresh water, the composition of which is replete with various kinds of heavy metals. Many of them, getting into the human body, have a detrimental effect on it, leading to severe poisoning, death. Such substances are called xenobiotics, that is, elements that are alien to a living organism. The class of xenobiotics includes such elements as cadmium, nickel, lead, mercury and many others.
Sources of water pollution by these substances are known. These are, first of all, metallurgical enterprises, automobile plants.
Natural processes on the planet can also contribute to pollution. For example, harmful compounds are found in large quantities in the products of volcanic activity, which from time to time enter lakes, polluting them.
But, of course, the anthropogenic factor is of decisive importance here.
radioactive substances
The development of the nuclear industry has caused significant harm to all life on the planet, including fresh water reservoirs. During the activities of nuclear enterprises, radioactive isotopes are formed, as a result of the decay of which particles with different penetrating abilities (alpha, beta and gamma particles) are released. All of them are capable of causing irreparable harm to living beings, since when they enter the body, these elements damage its cells and contribute to the development of cancer. 
Sources of pollution can be:
- atmospheric precipitation falling in areas where nuclear tests are carried out;
- wastewater discharged into the reservoir by nuclear industry enterprises.
- ships operating using nuclear reactors (in case of an accident).
Inorganic pollution
Compounds of toxic chemical elements are considered to be the main inorganic elements that worsen the quality of water in reservoirs. These include toxic metal compounds, alkalis, salts. As a result of the ingress of these substances into the water, its composition changes to be consumed by living organisms.
The main source of pollution is wastewater from large enterprises, factories, and mines. Some inorganic pollutants enhance their negative properties when in an acidic environment. Thus, acidic wastewater coming from a coal mine carries aluminum, copper, zinc in concentrations that are very dangerous for living organisms.
Every day, a huge amount of water from sewage flows into reservoirs.
Such water contains a lot of pollutants. These are particles of detergents, small remnants of food and household waste, feces. These substances in the process of their decomposition give life to numerous pathogenic microorganisms.
If they enter the human body, they can provoke a number of serious diseases, such as dysentery, typhoid fever.
From large cities, such effluents enter rivers and the ocean.
Synthetic fertilizers
Synthetic fertilizers used by humans contain many harmful substances such as nitrates and phosphates. Their entry into the reservoir provokes the excessive growth of a specific blue-green algae. Growing to a huge size, it prevents the development of other plants in the reservoir, while the algae itself cannot serve as food for living organisms that live in the water. All this leads to the disappearance of life in the reservoir and its swamping.
How to solve the problem of water pollution
Of course, there are ways to solve this problem.
It is known that most of the pollutants enter the water bodies together with wastewater from large enterprises. Water purification is one of the ways to solve the problem of water pollution. Business owners should attend to the installation of high-quality treatment facilities. The presence of such devices, of course, is not capable of completely stopping the release of toxic substances, but they can significantly reduce their concentration. 
Also, household filters that will clean it in the house will help fight drinking water pollution.
The person himself should take care of the purity of fresh water. Following a few simple rules will help to significantly reduce the level of water pollution:
- Use tap water sparingly.
- Avoid getting household waste into the sewer system.
- Clean up nearby waterways and beaches whenever possible.
- Do not use synthetic fertilizers. The best fertilizers are organic household waste, grass clippings, fallen leaves, or compost.
- Dispose of discarded trash.
Despite the fact that the problem of water pollution is now reaching alarming proportions, it is quite possible to solve it. To do this, each person must make some efforts, treat nature more carefully.
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2 Comments
Everyone knows that the percentage of water in the human body is large and our metabolism and overall health will depend on its quality. I see ways to solve this environmental problem in relation to our country: cutting water consumption rates to a minimum, and what is over - so at inflated tariffs; the received funds should be given for the development of water treatment facilities (cleaning with activated sludge, ozonation).
Water is the source of all life. Neither humans nor animals can live without it. I did not think that the problems with fresh water are so great. But it is impossible to live a full life without mines, sewers, factories, etc. In the future, of course, humanity will have a solution to this problem, but what to do now? I believe that people should actively address the issue of water and take some action.
Water pollution is a decrease in its quality as a result of various physical, chemical or biological substances entering rivers, streams, lakes, seas and oceans. Water pollution has many causes.
Wastewater
Industrial effluents containing inorganic and organic waste are often discharged into rivers and seas. Every year, thousands of chemicals enter water sources, the effect of which on the environment is not known in advance. Hundreds of these substances are new compounds. Although industrial effluents are pre-treated in many cases, they still contain toxic substances that are difficult to detect.
Domestic wastewater containing, for example, synthetic detergents ends up in rivers and seas. Fertilizers washed off the soil surface end up in drains leading to lakes and seas. All these reasons lead to severe water pollution, especially in closed lake basins, bays and fjords.
solid waste. If there is a large amount of suspended solids in the water, they make it opaque to sunlight and thus interfere with the process of photosynthesis in water basins. This in turn causes disturbances in the food chain in such pools. In addition, solid waste causes silting up of rivers and shipping channels, resulting in the need for frequent dredging.
Eutrophication. In industrial and agricultural wastewater that enters water sources, the content of nitrates and phosphates is high. This leads to a supersaturation of closed reservoirs with fertilizing substances and causes an increased growth of the simplest algae microorganisms in them. Blue-green algae grows especially strongly. But, unfortunately, it is inedible for most species of fish. Algae growth causes more oxygen to be taken from the water than can be naturally produced in it. As a result, the WPC of such water increases. Biological wastes, such as wood pulp or untreated sewage, entering the water also increase the WQD. Other plants and living beings cannot survive in such an environment. However, microorganisms that can decompose dead plant and animal tissues multiply strongly in it. These microorganisms absorb even more oxygen and form even more nitrates and phosphates. Gradually, in such a reservoir, the number of plant and animal species is significantly reduced. The most important victims of the ongoing process are fish. Ultimately, a decrease in oxygen concentration as a result of the growth of algae and microorganisms that decompose dead tissues leads to the aging of lakes and their waterlogging. This process is called eutrophication.
A classic example of eutrophication is Lake Erie in the United States. For 25 years, the nitrogen content in this lake has increased by 50%, and the phosphorus content by 500%. The reason was mainly the ingress of domestic wastewater containing synthetic detergents into the lake. Synthetic detergents contain a lot of phosphates.
Wastewater treatment does not give the desired effect, since it allows you to remove only solids from the water and only a small proportion of the nutrients dissolved in it.
Toxicity of inorganic waste. The discharge of industrial wastewater into rivers and seas leads to an increase in the concentration of toxic heavy metal ions, such as cadmium, mercury and lead. A significant part of them is absorbed or adsorbed by certain substances, and this is sometimes called the process of self-purification. However, in enclosed pools, heavy metals can reach dangerously high levels.
The most famous case of this kind occurred in Minamata Bay in Japan. Industrial wastewater containing methylmercury acetate was discharged into this bay. As a result, mercury began to enter the food chain. It was absorbed by algae, which ate shellfish; fish ate shellfish, and fish was eaten by the local population. The mercury content of the fish was found to be so high that it led to birth defects and deaths in children. This disease is called Minamata disease.
Of great concern is also the increase in nitrate levels observed in drinking water. It has been suggested that high levels of nitrates in water can lead to stomach cancer and cause increased infant mortality.
However, the problem of water pollution and its unsanitary condition is not limited to developing countries. A quarter of the entire Mediterranean coast is considered dangerously polluted. According to a 1983 United Nations Environment Program report on the pollution of the Mediterranean Sea, eating shellfish and lobster caught there is unsafe for health. Typhus, paratyphoid, dysentery, poliomyelitis, viral hepatitis and food poisoning are common in this region, and outbreaks of cholera occur periodically. Most of these diseases are caused by the discharge of raw sewage into the sea. It is estimated that 85% of waste from 120 coastal cities is dumped into the Mediterranean Sea, where tourists and locals swim and fish. Between Barcelona and Genoa, approximately 200 tons of waste is dumped per mile of coastline per year.
Pesticides
The most toxic pesticides are halogenated hydrocarbons such as DDT and polychlorinated biphenyls. Although DDT has already been banned in many countries, it still continues to be used in other countries, and approximately 25% of the amount of this substance used reaches the sea. Unfortunately, these halogenated hydrocarbons are chemically stable and not biodegradable. Therefore, they accumulate in the food chain. DDT can destroy all life on the scale of entire river basins; it also discourages bird breeding.
oil leak
In the US alone, there are approximately 13,000 oil spills each year. Up to 12 million tons of oil enter the sea water every year. In the UK, more than 1 million tons of used engine oil is poured into the sewers every year.
Oil spilled into seawater has many adverse effects on marine life. First of all, birds die - drowning, overheating in the sun or deprived of food. Oil blinds animals living in the water - seals, seals. It reduces the penetration of light into closed water bodies and can increase the temperature of the water. This is especially detrimental to organisms that can only exist in a limited temperature range. Oil contains toxic components, such as aromatic hydrocarbons, which are detrimental to some forms of aquatic life, even at concentrations as low as a few parts per million.
O.V. Mosin
Freshwater pollution has become so significant that it is a concern in many countries. The reasons for the pollution of rivers and lakes are the intensive development of industrial production and population growth, as a result of which the volume of industrial and domestic wastewater has increased significantly. For example, in the Moscow River, the concentrations of suspended solids, oil products, sulfates, phenols, ammonium nitrogen, heavy metal salts exceed the MPC from 2 to 20 times.
Petroleum products are very dangerous. They enter the rivers with effluents from oil producing, oil refining, automobile and railway enterprises, from transport and oil tankers. On the water surface, such substances form a film that prevents the penetration of oxygen into the water. Oxygen starvation leads to the death of different species of fish. For this reason, catches in many inland waters are greatly reduced. Oil pollution adversely affects other inhabitants of rivers and lakes.
The fauna of water bodies is adversely affected by wastewater from the pulp and paper industry. Oxidation of wood pulp is accompanied by the absorption of a significant amount of oxygen, which causes the death of eggs, fry and adult fish. Fibers and other insoluble substances clog water and worsen its physicochemical properties.
Mole alloys adversely affect the condition of fish and their food - invertebrates. From rotting wood and bark, various tannins are released into the water. Resin and other extractive products decompose and absorb a lot of oxygen, which leads to the death of fish, especially juveniles and eggs. In addition, mole alloys heavily clog rivers, and driftwood often completely clogs their bottom, depriving fish of spawning grounds and food places.
Nuclear power plants pollute rivers with radioactive waste. Radioactive substances are concentrated in the smallest planktonic organisms and fish, then they are transferred along the food chain to other animals. It has been established that the radioactivity of planktonic inhabitants is thousands of times higher than the water in which they live. The concentration of radioactive phosphorus in the body of freshwater fish is 20-30 thousand times, and in waterfowl 50 times higher than in a reservoir.
Waste waters with increased radioactivity (100 Ci per Gl or more) are subject to disposal in underground drainless pools or special reservoirs.
In connection with the growth of population, the expansion of old and the emergence of new cities, the flow of domestic wastewater into inland waters has significantly increased. These effluents have become a source of infection of rivers and lakes with pathogenic bacteria and helminths. Synthetic detergents, which are widely used in everyday life, as well as in industry and agriculture, pollute water bodies to an even greater extent. The chemicals contained in them, which came with wastewater into rivers and lakes, have a significant impact on the biological and physico-chemical regime of water bodies. As a result, the ability of water to saturate with oxygen decreases, and the activity of bacteria that mineralize organic substances is paralyzed. Pesticides used excessively and ineptly in agriculture, when they enter rivers and canals, also worsen the quality of water in them.
Distinguish between mineral and organic pollution of wastewater. In the first case, wastewater contains salts, acids, alkalis, clay, sand and other minerals. There are more than 40% of them in industrial effluents. Often, valuable raw materials (table salt, glycerin, acetic acid, chlorides, fertilizers, etc.) are thrown away, which also becomes a pollutant of fresh water.
Wastewater containing plant fibers, animal and vegetable fats, fecal matter, fruit and vegetable residues, waste from the leather and pulp and paper industries, sugar and breweries, meat and dairy, canning and confectionery industries, cause organic pollution of water bodies.
In wastewater, usually about 60% of substances of organic origin. This category also includes biological pollution (bacteria, viruses, fungi, algae) of municipal, medical and sanitary waters and waste from leather and wool washing enterprises.
The rivers are largely polluted as a result of the discharge of insufficiently treated agricultural, storm and municipal wastewater. The quality of wastewater has also deteriorated, especially as a result of an increase in the share of discharges from chemical industries. The most toxic effluents are sent to storage ponds. However, some of them from individual enterprises, where there are no treatment facilities, end up in rivers. Even in highly developed countries, water purification leaves much to be desired. Thus, in Germany, only 64% of domestic wastewater is treated, in Sweden, 10% of wastewater remains untreated, and 15% are subjected to only mechanical treatment.
Previously, when the volume of wastewater was insignificant, most enterprises did not build treatment facilities, but limited themselves to diluting these effluents with river water. It should be borne in mind that to dilute 1 m 3 of wastewater, 20--30 m 3 of natural clean water is needed. In modern conditions, the huge volume of wastewater cannot be diluted sufficiently. The applied cleaning methods can reduce the level of pollution by only 80%, and in more advanced facilities - up to 95%. At the same time, the cost of treatment facilities often reaches 10-20 % the cost of building enterprises. Only the transition to a closed water supply cycle is a radical means of solving this problem.
Enterprises located in rural areas heavily pollute water bodies. Here, measures are needed to treat wastewater from cheese, dairy, breweries, tanneries, wineries, canning factories, dairies, meat processing plants, fish factories, flax factories, depots, various workshops, garages, engine yards, warehouses for fuel and lubricants, fertilizers and pesticides, urban and settlement sewers, including baths and laundries.
It is impossible to place dairy-commodity and pig-breeding complexes near rivers and reservoirs, which heavily pollute water sources with waste. Livestock during grazing destroys shrubs and sod cover, which reduce the intensity of coastal erosion (abrasion). At livestock complexes, it is necessary to dispose of manure in a timely manner, create ramparts to intercept polluted runoff, establish places for watering and observe other operating rules. Manure accumulators should have isolated sections for keeping manure and neutralizing it from pathogenic microorganisms. They are laid taking into account hydrogeological conditions in order to exclude the filtration of slurry and its contamination of groundwater.
Recently, the term "irrigation pollution" has appeared. It is especially typical for the conditions of Central Asia, primarily for Karakalpakstan and Turkmenistan. Here, in many cases, the occurrence of groundwater turned out to be at the level of the sewerage and latrines. It is no coincidence that these regions have the highest number of gastrointestinal infections and the highest infant mortality rate in the CIS.
The Volga, Ural, and Dnieper rivers are especially heavily polluted. More than 7 billion m 3 of polluting water is discharged into the Volga annually, including more than 1 billion m 3 without treatment. Only in the region of Volgograd more than 230 million m 3 of such water enters the river.
Developing industry and irrigated agriculture, they did not take into account that the water resources of rivers make up a small part of the country's water reserves. As a result, such rivers as, for example, the Volga, were heavily polluted. In addition, the construction of dams and reservoirs associated with the construction of hydroelectric power stations has changed the hydrological regime of the river. If earlier water from Rybinsk to Volgograd reached in 50 days, now it takes 450-500 days. Most of the tributaries of the Volga, like capillaries that feed it, are polluted and clogged with earth. The self-purification of this mighty river has decreased tenfold. If earlier solid precipitation, coming with surface runoff from the territory of the basin, fertilized floodplain and flood lands, now they are deposited at the bottom of the reservoir. The fish began to be affected by helminths. This is also a consequence of the cascading of reservoirs, the low flow of the Volga. The basic level of saline soils has risen, they are not washed, and their fertility is declining. As a result of abrasion, 70 thousand hectares of land were lost. In this regard, the restoration of the hydrological regime of rivers becomes an important problem. It has already been resolved in relation to the lower reaches of the Volga. Now 130 m 3 of water is discharged from the Volgograd reservoir through the dam in spring, thanks to which the fish can spawn. And although in this case 1000 MW of electricity is lost, these losses are justified, because only in this way can the fish stock be saved. Environmental issues are the most important.
More than 40% of the cultivated area is treated with pesticides. About 1% of these substances get into water bodies from rainfed lands, and about 4% from irrigated lands. During aerial treatment, as a result of drift, up to 30% of the applied pesticides enter water bodies. Migrating in water, they are transported over long distances, and their biological decay due to stability is slow. The process of eutrophication of water bodies has become very menacing, when the development of phytoplankton, especially blue-green algae, is intensified - water blooms occur. Eutrophication in reservoirs is associated with leaching of biogenic elements from flooded soil and decay of vegetation on their bottom. But this process has especially intensified in connection with the discharge of domestic and industrial wastewater, the removal of mineral fertilizers and pesticides from the fields, and the violation of the hydrological regime of rivers. A negative role is also played by the fact that up to 1 million tons of manure is formed annually at livestock complexes, and only about 600 thousand tons of it are applied to the soil. A significant amount of organic fertilizers can enter water bodies and cause eutrophication.
Vessels that dump waste oils and household waste pollute water bodies.
Bacterial and chemical pollution of underground waters is increasing. bacterial contamination is typical for groundwater, but it is quite possible for microorganisms to enter artesian waters. Especially dangerous is the contamination of groundwater with chemicals that remain in them for a long time.
Much attention is paid to Lake Baikal, which contains 20% of the world's fresh water reserves. Mole rafting of timber along the rivers flowing into the lake is prohibited. Carry out work to clean the rivers from sunken wood. Temporarily banned fishing of the famous omul.
An unfavorable ecological situation has been created in this unique region. Measures have been developed to preserve the natural complex of the Baikal basin. Some of them are listed below.
Construction, reconstruction and expansion of facilities for wastewater treatment and gas emissions.
Ordering in accordance with the requirements of the ecology of shipping and transportation of goods on the lake.
Creation of efficient installations for cleaning flue gases from sulfur compounds and equipping them with Gusinoozerskaya State District Power Plant and Ulan-Ude Thermal Power Plant, and other enterprises.
Implementation of measures to ensure strict compliance with the standards of maximum permissible emissions of pollutants into the atmosphere by the Baikal pulp and paper and Selenginsky pulp and paper mills.
Re-profiling of the Baikal Pulp and Paper Mill for environmentally friendly production.
Implementation and efficient use of farm animal manure and wastewater from agricultural facilities.
Implementation of measures aimed at improving the water protection and soil protection properties of the forests of the lake basin.
Improving the system for monitoring the state of the natural environment in the region.
Establishment of the International Center for Nature Conservation.
