Human existence without clean drinking water is impossible. Unfortunately, today there is such a situation that the number of clean sources on Earth is significantly reduced. Now the shortage of clean drinking water is replenished with the help of various water treatment equipment, but the forecast of scientists is rather pessimistic - in a few decades, polluted waters on Earth will prevail.

If you turn to scientific terms, then water pollution is a change in its chemical and physical condition, as well as its biological properties, which leads to unsuitability for consumption. For any type of use, water changes its state: when heated, it changes physical properties, when delivered to consumers, chemical properties, even if it has previously passed through.

Toxic substances enter the aquatic environment from natural as well as anthropogenic sources. Natural sources of water pollution- this is the destruction of rocks, volcanic activity, the release of waste products of various organisms that live in water bodies. Humans also contribute to water pollution through economic activity. Its impact on natural ecosystems has been compared to a natural disaster. This is explained by the fact that all the water bodies of the planet are changing too quickly over the past few years, with natural processes such changes occur over hundreds of years.

The intensive development of agricultural and industrial production and population growth are anthropogenic sources of pollution. Agricultural, domestic and industrial wastewater is discharged into water bodies, as a result of which the composition of water changes. Anthropogenic sources of water pollution can be divided into primary and secondary. In the first case, the quality of water deteriorates due to the ingress of pollutants.

In the second case, an excessive concentration of waste products of aquatic animals and their remains appears, which is caused by a violation of the ecological balance. Let's list the main sources of water pollution:

• river transport;
• river rafting;
• industrial domestic waste water;
• runoff from livestock complexes;
• drainage water from irrigated lands;
• runoff from the territories of industrial sites, territories of settlements and agricultural fields;
• storm sewer;
• global transfer;
• solid runoff from lands that have lost their fertile layer.

The World Health Organization offers a different classification:

• bacteria, various viruses and other pathogens;
• decaying organic matter absorbed by water oxygen. They bring to the appearance of an unpleasant odor, worsen the taste of water and have a detrimental effect on fish stocks;
• inorganic salts that cannot be removed by conventional methods. These substances make the water unsuitable for drinking and irrigation;
• organic salts that enhance the growth of aquatic vegetation and cause flowering of reservoirs.

They turn into organic matter during photosynthesis and are deposited at the bottom of the reservoir. Pollution of water bodies with toxic substances is very dangerous for human health. They represent a direct and indirect danger through animals that live in water bodies.

Experts put it all together sources of water pollution and identified three main categories, each of which, in the presence of modern facilities, still pollutes both surface and groundwater (wells and artesian wells). Let's take a closer look at these categories.

Settlements

Even in the most modern settlements, the main household waste is sewage. Each person uses approximately 750 liters of water daily for drinking, cooking, hygiene purposes, as well as for watering lawns, washing streets, fighting fires, and so on.

Industry

The main consumers and pollutants are enterprises of various industries in countries with developed industrial production. The amount of wastewater they emit is three times the amount of domestic wastewater.

How a person pollutes the hydrosphere, you will learn from this article.

How do humans pollute water?

Hydrosphere is an aquatic environment that includes groundwater and surface water. Today, man's activities have led to massive water pollution.

Main types of pollution:

• Pollution by oil products and oil. Oil slicks prevent sunlight from reaching the water column and slow down the process of photosynthesis.
• Waste water pollution due to mineral and organic soil fertilization and industrial production. Algae in water bodies begin to multiply actively and lead to swamping and death of other ecosystems.
• Contamination with heavy metal ions.
• Acid rain.
• radioactive contamination.
• Thermal pollution. Emissions from nuclear power plants and thermal power plants contribute to the development of blue-green algae and water bloom.
• mechanical pollution.
• Biological and bacterial pollution contributes to the development of pathogenic organisms and fungi.

How does man pollute the ocean and seas?

Every year more than 10 million tons of oil enters the Ocean. Today, about 20% of its area is covered with an oil film. Particularly acute is the problem of pollution by industrial waste and household waste. Often marine inhabitants swallow plastic, bags and die either from suffocation or from the fact that this debris gets stuck in the body. A serious environmental threat to the oceans and seas is the burial of radioactive waste by humans and the dumping of radioactive liquid waste.

How do people pollute rivers and lakes?

In the process of human industrial activity, a large amount of oil products, wastewater, and radioactive liquid substances enter the waters of lakes and rivers. Pesticides are especially dangerous. Once in the water, they instantly dissipate and reach the maximum degree of concentration. Waste nuclear fuel and weapons-grade plutonium destroy the fauna of these water bodies.

How do people pollute groundwater?

They suffer greatly from oil fields, filtration fields, the mining industry, slag accumulators, storage facilities for chemical fertilizers and waste, dumps of metallurgical plants, and sewers. As a result, groundwater is polluted with phenols, copper, zinc, oil products, nickel, mercury, sulfates, and chlorides.

We hope that from this article you have learned how a person pollutes water.

The waters of our planet are located on the surface and underground. Surface water is 98% oceans. The area of ​​the oceans is almost 2.5 times larger than the surface of the earth. Most of the water in the oceans is salty with an average temperature of 3.7 degrees. Surface and coastal waters have lower salinity and higher temperatures. Below 60 meters, the water begins to reduce oxygen levels. Water pollution and methods of its purification are considered today in all spheres of human activity.

Underground springs may contain saline, less saline, or fresh water. Geothermal springs are also distinguished separately, in which the water temperature is above 30 degrees.

A person uses only fresh sources, which are less than 3% on our planet. Only 0.4% of this water is easily extracted, and the rest requires special equipment for various purposes. A lot of fresh water is contained in the snow and ice of the South Pole. Fresh water sources are rivers and underground springs. But on Russian territory, most of the river flows are in the north, where the land is barren and sparsely populated.

If there is no fresh water nearby, then sea water is used, which is subjected to hyperfiltration to remove salts. To do this, polymer membranes with small pores are used, which do not allow salt molecules to pass through. But the process is quite expensive and rarely used. Preference is given to icebergs towed to the coast and subjected to melting. The method of providing fresh water is half as energy intensive. However, 80% of infectious diseases are transmitted by this water.

Water pollution

Water is at the core of earthly life. Huge air pollution caused damage to soils, rivers, reservoirs. Most substances from the air settle on the earth's surface. But that's only part of the problem. Water pollution occurs when waste directly enters water sources. Agricultural fields today are treated in large volumes with pesticides and fertilizers. Numerous landfills are created. Industrial wastewater is discharged into rivers.

The main source of fresh water, groundwater, is polluted. Dangerous substances in the water return to people and poison their body.

What kind of water does a person use? Natural water is always enriched with gases, salts and solid impurities. Fresh springs contain up to 1 gram in 1 liter of salts.

Pollution reduces drinking water sources

Fresh water comes to nature through the water cycle. More than 500 cubic meters of water are evaporated every year, 86% of which is salty. A certain amount returns to the ocean in the form of precipitation, and the other is carried by air masses to the earth's surface and replenishes rivers and lakes, groundwater and glaciers.

Only 2% of the hydrosphere consists of fresh water, which is constantly being renewed. It is the speed that determines the available fresh water resource.

85% of fresh water is located in glaciers and ice at the Pole. There, water exchange takes place over 8 thousand years. For comparison, in rivers, the renewal period is up to 12 days.

Today, rivers are not only a source of vital water, but also a carrier of hazardous waste.. Industrial wastewater is collected in the territories and flows along the riverbed to the seas and oceans.

All the time, the number and level of treatment facilities do not have time to grow with the development of industry. But this is not the main problem. The best purification of polluted water is not able to remove dissolved substances and a tenth of organic matter. For reuse, water must be diluted with a large volume of new water. For people, the absolute volume of sewage plays an important role.

Today, 1/5 of the total volume of fresh water is diluted with treated wastewater. This means that the resource will soon run out. The volume and quality of fresh water is decreasing every year.

Man must find other ways to use water. The anthropogenic water cycle must be isolated from the natural one. That is, it is necessary to ensure a closed cycle of water use. Technologies should be low-waste or waste-free with a decrease in the amount of water consumed.

Lots of fresh water. However, the wrong attitude towards it will lead to the depletion of any source. Every year on the planet the number of such places increases significantly. Now 1/5 of the urban population and ¾ of the rural population are experiencing a shortage of fresh water. Each person consumes 3-700 liters of water every day. Individual need depends on the standard of living and place of residence.

Most of the fresh water is used for agricultural purposes. Irrigated lands give 50% of the crop, occupying only 15% of agricultural land.

Today the flow of rivers is changing and a lot of water is not returned back to the rivers. It evaporates and forms a plant mass: during synthesis, aqueous hydrogen forms organic substances. About 1.5 thousand reservoirs have been built on the territory of Russia to solve the problem. But they solve the problem of only 9% of the rivers.

Water pollution by effluents of various origins

Allocate industrial, agricultural and domestic effluents. They decompose under the influence of microorganisms that need oxygen dissolved in water. With a sufficient concentration of it, aerobic bacteria process dangerous impurities into harmless substances. With a deficiency, the death of aerobic bacteria and rotting of water is observed. Fish also suffer, especially during the spawning season.

Viruses and dangerous microorganisms enter the water from sewage, domestic and livestock waters. If you do not organize the purification of polluted water, then outbreaks of epidemics are observed. Today, in developed countries, epidemics are rarely caused by tap water. Vegetables and fruits that are watered with sewage are also poisoned. The inhabitants of polluted seas and oceans, which people love to eat, are sources of typhoid infection.

Nitrates and nitrites in fresh water ax cause eutrophication, which leads to a decrease in the oxygen concentration in the water. It also has a bad effect on the human body.

Today there is an increased concentration of metals, oil products, pesticides, phenols and synthetic detergents in the water. Many substances do not break down in water or decompose for a very long time, which leads to their accumulation in the food chain.

These precipitations are the hydrological consequences of urban growth. Agriculture is carried out according to disturbed technologies, deforestation, violation of river flow, which provokes soil erosion. The balance in the environment is disturbed, benthic organisms suffer.

thermal pollution

Thermal pollution includes warm water from industrial and thermal power plants. With an artificial increase in temperature in nature, the concentration of oxygen in water decreases and metabolism changes. The death of many inhabitants of reservoirs or suppression in their development is observed.

Even 10-20 years ago, pollution was located in local areas. Today it represents one array on a vast territory.

Oil pollution

Pollution by oil products is the most frequent in world practice today. The two largest oceans, the Pacific and the Atlantic, are today 4% permanently covered with a film of oil. The main sources are its transportation and development. From the continents, oil enters through river waters. Every year it is about 2 million tons of oil products.

Oil forms a centimeter film on the surface. Later, an emulsion of water and oil begins to form, long-lived lumps of fuel oil appear, to which small marine inhabitants stick. They become easy prey for predators. However, in addition to food, oil products also enter the body, poisoning the body of the fish. It cannot be used for food due to its bad taste and smell.

The marine life community is dwindling and changing dramatically. Microorganisms begin to actively develop, for which oil products are the main food. For many inhabitants, this is a poisonous biomass.

The pitfall is that petroleum hydrocarbons dissolve pesticides and metals. All this becomes more toxic and poisonous.

The aromatic fraction leads to the mutation of the marine environment. If you eat food with them, then the risk of mutation of human cells increases - cancer.

Oil poisons surface waters. But they are considered the "kindergarten" of most populations. Disturbed gas exchange of water and atmosphere, heat transfer.

In birds, oil sticks together feathers, which prevents it from swimming and establishing proper thermal insulation.

Crude oil in the ocean or sea does not pose much of a long-term hazard to aquatic life. Oil products are more dangerous - diesel, gasoline, etc. The high oil content in the tidal zone also causes harm.

Other types of water pollution

For several decades, chlorination has become widespread. Chlorine is used in agriculture, forestry, and urban wastewater treatment plants to fight infections. Today in the oceans there is a fairly high concentration of this chemical element, which is brought by rivers and the atmosphere. Even in Antarctica and the Arctic, DDD has been found.

Polychlorinated biphenyls are readily soluble in fats. It is collected in the organs of the inhabitants of the marine environment. Since they are of artificial origin, there are no creatures in nature that consume them for food. Xenobiotics do not decompose, but only accumulate in nature, including the World Ocean. They are toxic, adversely affect the circulatory system and enzyme activity, heredity suffers.

River runoff also carries heavy metals, some of which are toxic, into the oceans. About 2 million tons of lead, 10 thousand tons of mercury, 20 thousand tons of cadmium enter the World Ocean annually.

A third of the mercury and half of the lead end up in the ocean from the atmosphere.

Consequences of sewage pollution

Infectious diseases

Wastewater is the main source of pathogenic infections. Sick animals and people shed a lot of eggs and pathogens. There are cases when a person is not even aware of his illness. If drinking water, food sources or bathing areas are contaminated by sewage, many people become infected. Sometimes pathogenic bacteria are passed down the food chain from marine life.

The pathogenic organism, on average, lives only a day outside the host. The development of an infectious disease depends on their number. At a low density, the transfer and transmission of infection is significantly small. People in densely populated cities are at greater risk.

In many countries, mandatory sanitary and hygienic standards have been introduced, which provide for:

• water disinfection by chlorination or other methods;
• hygiene and sanitation while working with products;
• proper collection and treatment of polluted water.

Decreased oxygen concentration

Organic constituents in sewage water are consumed by microorganisms that use the oxygen dissolved in water for respiration. A large number of organisms do not allow oxygen to be replenished naturally. For bacteria, oxygen is not so important, since they are capable of anaerobic respiration, fermentation. Creatures that cannot do without oxygen suffer.

The risk of microbial contamination increases: the anaerobic environment is favorable for many pathogenic organisms.

Collection and treatment of waste water

Organization of primary wastewater

The sanitary sewer system collects waste pipes and isolates waste water from sinks, bathtubs, etc. A large consumption of clean water or just an open tap leads to a low concentration of waste in the water - 0.1%. If you take into account storm water, the figure will be even less.

There are three groups of pollutants in primary effluents:

• sand and garbage (garbage comes from toilets, and sand comes from storm drains);
• living and non-living organics: paper, fabric, food, excrement, etc.
• dissolved substances: phosphorus, nitrogen, potassium, manganese, etc.

Cleaning steps

For complete cleaning, all listed contaminants must be removed.

Sand and debris are easily removed by pre-cleaning.

Primary and secondary purification is necessary to eliminate colloidal organic compounds. From biogens, a special post-treatment is provided.

You should be aware that wastewater does not always go through all the stages of treatment. You can find places where untreated sewage is discharged into the water or only after primary treatment. In other cities, secondary treatment and sometimes post-treatment can be carried out.

Pretreatment

Sand and debris impede the movement of wastewater through the system. Their elimination is considered a preliminary stage of cleaning.

Garbage is removed using rod grates: the rods are fixed every 2.5 cm. Garbage is collected and incinerated in an oven.

Primary cleaning

Water passes through primary settling tanks - large tanks. She doesn't move at all for a couple of hours. 35-55% of heavy particles, including those of organic origin, settle to the bottom. At the same time, fats and oils rise to the surface. They are drained like cream. The collected pollution is called raw sludge.

Primary cleaning requires a minimum of costs with high efficiency. But 45-65% of biogen and colloids remain in the water.

Secondary cleaning

Secondary treatment removes the remaining organics, but not dissolved substances. It is also called biological treatment. Reducers and detritophages are used, which "eat" organic matter and produce carbon dioxide and water. Activated sludge and a drip biofilter are most often used.

In drip biofilters, water is sprayed onto the walls of stones. A natural ecosystem is formed with bacteria, detritus feeders, worms, etc. Then the water enters the secondary settling tanks to remove the washed-off organisms. After the drip filter, the water is 90% purified from organics.

Another way is activated sludge. Water goes to the reservoir, where a mixture of detritus feeders is added. In the process of immersion, water is enriched, aerated and beneficial microorganisms multiply. They eat organic matter, pathogenic organisms, etc. After that, the water should settle to remove detritophages. They are collected in groups, easily removed and reused. Efficiency of purification of polluted water - 95%.

But secondary treatment does not remove nutrients. Even 20 years ago, people did not think about them. Water was simply treated with chlorine and descended into reservoirs. Somewhere this method of cleaning has been preserved to this day. But big cities begin to introduce additional methods of purification - post-treatment.

Post-treatment

Nutrients can be removed in various ways. For example, microfiltration or distillation, which are 100% efficient. But it's very expensive. Today they are working on new ways to clean the ode. For example, phosphates are removed with lime: calcium and phosphate form an insoluble substance that is easily filtered out of the water. But with a high concentration of phosphates, the method will be ineffective.

Proper post-treatment can make water drinkable. Some people find it unpleasant to think that we are drinking treated wastewater. But in nature, water always makes a cycle. It may turn out that the water after post-treatment is much better than from rivers into which untreated sewage was discharged.

Disinfection

No matter how the water is purified, they strive to disinfect it before being released into the reservoir. This is the only way to kill pathogenic organisms. Use chlorine. However, it is highly poisonous, and its delivery threatens humans. Fish suffer from chlorine. If it reacts with organics, then insoluble compounds are formed that do not decompose and are very toxic. They cause cancer, developmental disorders of the embryo and the functioning of the reproductive system.

Safe is ozone, which kills microorganisms and forms oxygen when they decompose. But it is also toxic and can cause an explosion.

New methods are considered to be UV radiation, which has no side effects.

For iron removal it is necessary to use an integrated approach. There are no universal rules. There are reagent and non-reagent cleaning methods. They resort to the following methods:

• aeration - ensuring intensive oxidation with a large air supply;
• treatment with strong oxidizing agents - chlorine, potassium permanganate, ozone, etc.;
• modified loading - special materials that mechanically and chemically remove all the iron in the water.

The presence of iron in water is easily determined by sedimentation and the metallic taste of water. Household appliances, surfaces of sinks and bathtubs, heating systems, etc. suffer.

Removal of hardness salts

Every housewife knows about hard water. It leaves a coating on the heating elements, prevents detergents from foaming. Hard water is not suitable for the food industry. Magnesium and calcium bicarbonates are to blame for everything, which, when boiled, change their form to an insoluble one.

The following methods are used to soften water:

• thermal - heating water;
• freezing;
• using reagents;
• ion exchange;
• reverse osmosis;
• electrodialysis;
• combined.

There are enterprises that discharge hazardous wastewater with mercury, lead, chromium, organics, etc. into the sewer. Sometimes it is not possible to completely clean wastewater from all impurities: there are no financial or technical possibilities. Impurities begin to interfere with biological treatment, killing the desired microorganisms.

When untreated water is used in agriculture, soils deteriorate and harmful products grow.

Today, the legislation is not able to control compliance with all norms and rules for the treatment of polluted water.

Greetings dear readers! Today I will tell you about fresh water pollution...

Fresh water pollution, in most cases, remains invisible because the contaminants are dissolved in the water.

But there are exceptions too: oil products floating on the surface, foaming detergents, untreated drains.

There are several natural pollutants. Soil contains certain nutrients, such as nitrates, which come to the surface when plowing old pastures and are washed away by surface runoff.

Aluminum found in the ground enters the freshwater system through a series of chemical reactions. Floods leach magnesium from the soil of meadows, which causes great damage to fish stocks.

However, the amount of semi-natural and natural pollutants is nothing compared to those produced by man.

Types of pollutants.

Farmers use a variety of chemicals that end up in fresh water: insecticides, fungicides, acaricides, herbicides, and sheep disinfectant, which contain a total of 450 biocide active ingredients.

Phosphates and nitrates, which stimulate plant growth, are introduced into the ground, and poultry farms, pig farms and silos are a source of a large amount of toxic effluent.

In addition to disinfectants, fresh water is also contaminated by pharmaceuticals used in agriculture - hormones, antibiotics and growth inhibitors.

Also, along with household waste through the sewer, hormonal preparations enter the water.

Chemical reagents are used to produce drinking water. And traces of these reagents remain in the water. A by-product of water chlorination is trihalomethane, which is considered carcinogenic.

In 1988, the use of aluminum sulfate in water purification was widely reported in the press: then several tons of this substance were dumped into the water supply system of an English town, which caused mass illness among local residents.

Heavy metals: lead, cadmium and zinc are the most dangerous industrial pollutants.

Acid rain (more on acid rain) caused by the burning of fossil fuels is another serious source of freshwater pollution.

Sources of pollution.

Pollutants enter fresh water in various ways, indirectly or directly, but always with the participation of man: as a result of leaks and spills, deliberate dumping of waste, as a result of accidents.

Farms are the largest potential sources of pollution. In Wales and England, farms occupy almost 80% of the land.

Some of the untreated animal manure that covers the soil penetrates into fresh water sources.

In addition, farmers in Wales and England annually apply 2.5 million tons of nitrogen, potassium and phosphorus to the soil, and some of these fertilizers end up in fresh water.

Some of these are persistent organic compounds that find their way into food chains and cause environmental problems.

The UK is now curtailing the production of organochlorine compounds, which were produced in large quantities in the 1950s.

Freshwater bodies are increasingly threatened by effluents from fish farms due to their extensive use of pharmaceuticals to control fish diseases.

Sources of a large number of nutrients that enter fresh water, cadmium, aluminum and iron, are primarily forestry and open drainage.

The acidity of the forest soil increases with the growth of trees, and heavy rains form very acidic runoff, which is detrimental to wildlife.

The cause of a serious environmental disaster can be slurry in the river. Because its concentration is 100 times greater than that of wastewater treated at wastewater treatment plants.

Atmospheric pollution of fresh water is especially detrimental. There are 2 types of pollutants: gases (nitrous oxide and sulfur dioxide) and coarse gases (droplets of liquids, ash, dust and soot).

They are all products of agricultural and industrial activity. Concentrated acids, nitric and sulfuric, are formed when these gases combine with water in a raindrop.

Spreaders of pollutants.

As a result of the so-called leaching, solid and liquid pollutants enter the water supply from the soil surface.

A small amount of waste dumped on the ground is dissolved by rain and enters the groundwater, and then into local rivers and streams.

In fresh water sources, liquid waste penetrates faster. Crop spray solutions, on contact with the soil (more information on soil), either lose their potency or leach into the ground, seeping into groundwater or entering local rivers.

Up to 80% of these solutions are wasted because they end up on the soil and not on the sprayed object.

The time required for pollutants (phosphates or nitrates) from the earth's surface to penetrate into groundwater is not exactly known, but this process, in many cases, can take tens of thousands of years.

Industrial drains - it's coming in environment pollutants from industrial plants.

Determining the level of pollution.

Signs such as dead fish can indicate contamination, but there are also more sophisticated methods to detect it.

Freshwater pollution is measured in terms of biochemical oxygen demand (BOD) – that is, how much oxygen a pollutant absorbs from the water.

This indicator allows you to assess the degree of oxygen starvation of aquatic organisms, for which oxygen is vital.

For clean rivers in Europe (more about this part of the world), the BOD norm is 5 mg / l, compared with untreated domestic wastewater - 350 mg / l.

Milk causes great harm when drained of its excess; the pollution it causes is 400 times greater than from domestic sewage.

Impact on wildlife.

The greening of the surface of the water is one of the most obvious signs of fresh water pollution. Flowering of aquatic plants here is observed when the water is enriched with a mixture of organic compounds leached from the surrounding soil.

The situation that has developed in the last 20 years is alarming because a significant part of the 500 reservoirs in England have become green and toxic due to their pollution.

Fresh water is turning into a breeding ground for potentially dangerous species of fungi, protozoa and bacteria.

Bacteria such as Listeria and Salmonella, as well as protozoa such as Cryptosporidium, are no less dangerous for human health than cholera in 19th century Europe.

On the surface of the water, greenery acts like a thick forest canopy, sunlight. Algae, which produce oxygen, are detrimental to this. The life of aquatic vertebrates and invertebrates depends on these algae.

Certain types of blue-green algae, in addition, emit toxic substances that kill fish and other aquatic organisms.

As a result, during the summer months, many recreational activities near the water are banned due to toxicity and algae growth.

Algae blooms in water bodies and lakes can also be caused by fertilization of forest soil and deforestation - nutrients in both cases enter the water.

In northwestern Europe, the United States (more on this country) and Canada, a series of major environmental disasters have caused acid rain.

In 16,000 of the 85,000 lakes in Sweden, the water has oxidized, and in 5,000 of them, the fish have completely disappeared. Lime has been added to the water of 4,000 lakes since 1976 to restore the chemical balance and neutralize the acid.

Norway and Scotland resorted to the same measures, where fish stocks were reduced by 40% for a similar reason.

In the eastern United States, the loss of trout caused by the acidification of sport fisheries has cost $1 billion annually.

However, other communities are paying for the liming of the lakes. So, for example, an excess of calcium led to the death of 90% of the moss growing near moss, cuckoo flax and peat moss.

A significant part of acid rain comes to Scandinavia from the west, where the British industry produces about 3.7 million tons of sulfur dioxide per year.

Pollution of water bodies, as a rule, leads to the death of wildlife, fish in the first place. But re-colonization and restoration of populations is possible, especially with human help.

Some invertebrates migrate to affected areas from upstream areas; others fly here in a matter of hours.

Some organisms are sensitive to ecological imbalance (such as river limpets, whose gills become clogged with silt), while other species are unaffected by rather high levels of pollution.

Tubeworms eat bacteria and larvae different types bells, and leeches easily tolerate eutrophication and low oxygen content.

Heavy metals.

Lead is found in dissolved form in fresh water. Fishing weights are one source of lead pollution. These sinkers are constantly thrown away when entangling the fishing line.

Swans suffer greatly from lead, swallowing weights along with algae. It remains in the muscular stomach of birds, gradually dissolving and causing their death.

A "broken neck" (when the muscles cannot support the bird's long neck and as a result it slowly starves to death) is a sign of lead poisoning.

Cadmium, other heavy metal, penetrating into the freshwater environment, affects fish, and through them enters the human body.

Purification of the waters of the Thames.

One of the dirtiest rivers in the world has long been the Thames, and for most of the 20th century it was free of fish.

As a result of long-term efforts, about 100 species of fish, including salmon, have reappeared here. Success was ensured by the control of industrial effluents at the places of their discharge and the prosecution of violators.

In tidal rivers such as the Thames, a solid mass of runoff can remain in their waters for weeks, going downstream 16 km at low tide and returning 15.3 km at high tide.

Drinking water is taken from the Thames along the entire channel. Water is each time brought to drinking standards, used, polluted, purified and dumped back into the Thames.

This cycle repeats itself all the time. And it can be said with certainty that a significant part of the waters that flow past the Houses of Parliament has passed through the kidneys of many people.

Immediately, the cleaning of the rivers of the Thames was crowned with great success, in contrast to the rivers of the USA and Germany (more on this country). In the United States, one of the bridges in Ohio burned down once, as a result of a fire on the surface of the water, contaminated with a large amount of oil products.

Legislation.

An effective means of preventing pollution is laws. But it is very difficult to enforce them.

Therefore, a new international initiative -“the party responsible for the pollution pays” is ideal in essence, but rarely bears fruit.

The European Community issues directives on water quality, but the governments of European countries are in no hurry to comply with these requirements.

In 1992, 9 out of 12 EU member states exceeded the level of nitrate in their water bodies.

All EU members were required, under new legislation, to set up by 2002 special treatment plants for the treatment of water for industrial and municipal consumption in order to prevent river pollution.

This work has been completed in most countries.

So we got acquainted with fresh water pollution and now, I hope, we will try to take environmental measures 🙂

Water pollution

Any actions performed by a person with water lead to a change in how it physical properties(for example, when heated), and chemical composition (in places of industrial effluents). Over time, the substances that have fallen into the water are grouped and remain in it already in the same state. The first category includes domestic and most industrial effluents. The second group includes various types of salts, pesticides, dyes. Let's take a closer look at some of the polluting factors.

Settlements

This is one of the main factors affecting the state of water. Liquid consumption per person per day in America is 750 liters. Of course, this is not the amount that you need to drink. A person consumes water when washing, using it for cooking, using the toilet. The main drain goes to the sewer. At the same time, water pollution increases depending on the number of inhabitants living in the settlement. Each city has its own treatment facilities, in which sewage is cleaned from bacteria and viruses that can seriously harm the human body. The purified liquid is dumped into the rivers. Pollution of water with domestic wastewater is also enhanced because, in addition to bacteria, it contains food residues, soap, paper and other substances that negatively affect its condition.

Industry

Any developed state should have its own plants and factories. This is the largest factor in water pollution. The liquid is used in technological processes, it serves both for cooling and for heating the product, various aqueous solutions are used in chemical reactions. More than 50% of all discharges come from the four main liquid consumers: oil refineries, steel and blast furnace shops, and the pulp and paper industry. Due to the fact that the disposal of hazardous waste is often an order of magnitude more expensive than their primary treatment, in most cases, along with industrial effluents, a large amount of a wide variety of substances is discharged into water bodies. Chemical pollution of water leads to a violation of the entire ecological situation in the whole region.

thermal effect

Most power plants operate using steam energy. Water in this case acts as a coolant, after passing through the process, it is simply discharged back into the river. The temperature of the current in such places can rise by several degrees. Such an impact is called thermal water pollution, but there are a number of objections to this term, since in some cases an increase in temperature can lead to an improvement in the environmental situation.

Oil pollution of water

Hydrocarbons are one of the main sources of energy on the entire planet. The collapse of tankers, gusts on oil pipelines form a film on the water surface through which air cannot enter. Spilled substances envelop marine life, which often leads to their death. Both volunteers and special equipment are involved in the elimination of pollution. Water is a life-giving resource. It is she who gives life to almost every creature on our planet. A negligent and irresponsible attitude towards it will lead to the fact that the Earth will simply turn into a desert scorched by the sun. Already, some countries are experiencing water shortages. Of course, there are projects to use arctic ice, but the best solution to the problem is to reduce the overall water pollution.