The main disadvantage of tap water is the excess of sulfites and bicarbonates, magnesium and calcium salts, as well as iron. In everyday life, water that has an unpleasant taste is called hard. You can tell whether water is hard or not by taking just one sip. If we add to this the residual chlorine content after mandatory disinfection, then the liquid entering the apartment will hardly quench your thirst.
In addition to the unpleasant taste and smell, tap water also has other unpleasant properties. The impurities contained in it can accumulate in the body and negatively affect the performance of internal organs; traces of salts are noticeable on the dishes, and even on household appliances a limescale deposit is formed that disables it.
Water settling - sequence of actions
To obtain water of decent quality, many use methods available at home. The simplest of these methods is settling tap water, which helps, under the influence of natural gravity, to settle suspended particles and get rid of chlorine dissolved in the liquid.
The essence of the settling method is expressed as follows:
- fill a clean container with tap water;
- the vessel is closed and left alone for several hours;
- within five or six hours, fairly large impurities, some heavy metal salts, particles of oxides and other contaminants, settle at the bottom of the container, and some of the chlorine evaporates;
- It is reasonable to use only the upper two-thirds of the settled water; it is better to pour out the rest, getting rid of harmful substances that have not had time to settle.
It is not worth allowing tap water to settle for longer than this period, since it will inevitably begin to multiply pathogenic flora, including bacteria dangerous to humans.
Safety of settled water
The undeniable advantage of this method is its simplicity and accessibility, but there are much more disadvantages.
The water entering the network centrally passes through mechanical purification filters and a disinfection system, part of which is chlorination. But the path to the water tap does not end there. Water does long journey through pipes whose condition is not always ideal. Therefore, when you open a water tap, instead of a clear stream of water you see, for example, a brown liquid. This is due to excess iron content, but this is only visible part iceberg of problems.
From the walls of dilapidated pipes, the flow of water washes away not only rust particles, but also other dangerous compounds, as well as viruses, bacteria and pathogenic microorganisms. In addition, not all impurities are capable of forming sediment. An example of this is colloidal iron, which looks like a brown jelly-like mass on inner surface water pipes. Simple settling of tap water is no longer effective against such contaminants.
Increasing efficiency when settling water
Activated carbon will help make water purification more effective by absorbing harmful substances, including pesticides and heavy metals, radon and chlorine compounds. Such filters with activated carbon increase the cleaning efficiency, and within a few hours the water becomes suitable for drinking.
But the low settling efficiency does not allow satisfying all human needs for clean water:
- the process takes too long;
- a large proportion of unused liquid;
- there is no guarantee that all sources of danger will be neutralized.
Therefore, if it is necessary to use tap water as drinking water, it is much more effective to use more productive methods, for example, pre-treatment, rather than settling.
Opting for pre-cleaning instead of settling
Leading manufacturers of water treatment equipment, including BWT, offer effective water treatment systems involving modern multi-stage treatment.
- Initial filtration of tap water allows you to remove mechanical impurities from it and thereby protect the equipment in the house, plumbing equipment and shut-off elements on pipelines.
- The second stage of water treatment ensures dosing and prevents massive lime deposits on the heating elements of home appliances and heaters.
- The third stage is a fine purification of tap water, turning it into drinking water of the highest quality.
Only the consistent use of all types of filters makes it possible to obtain the amount of completely safe drinking water necessary for a comfortable life.
An enterprise called Gorvodokanal, which provides water supply, guarantees its quality. The water supplied to our homes as drinking water is regularly tested by Rospotrebnadzor and actually meets the standards and requirements, being completely harmless. Why do we avoid drinking tap water if it is not harmful to our health?
The whole point is that water enters the water distribution system, where it can be subject to secondary contamination. It is there that clean water, that is, having gone through a full purification cycle, becomes cloudy, acquires an unpleasant tint, begins to give off chlorine, sulfur or metallic odors, and acquires an off-flavour. That is, it becomes not only unpleasant to drink, but also harmful to health.
There is a way out - this is high-quality water treatment, that is, the use of a set of measures for water purification. This improves its safety to some extent, but does not make household water healthy.
Advantages and disadvantages of drinking boiled water
This means that tap water must be boiled before it can be safely used for drinking? Of course, the boiling process will purify water from pathogenic microorganisms, significantly reduce the amount of volatile substances that worsen the properties of water, but at the same time increase the concentration of non-volatile substances. Indeed, during the boiling process, the volume of water decreases, but the amount of salts and other chemical compounds remains the same.
How dangerous chlorine is in general depends on the amount of it. In small concentrations, which are typical for tap water, chlorine is not dangerous. In fact, chlorine is always added, it is necessary to purify water, then some part evaporates, and some remains in dissolved form. However, in solution, combining with organic substances that may be present in water, chlorine forms the carcinogenic substance trichloromethane (chloroform). Thus, boiling water does not make water healthy, it only slightly reduces the danger of drinking it.
What water is most beneficial for drinking?
Then perhaps you should drink distilled water? There is an opinion that it is she who is the purest, but this is not entirely true. The distillation method that produces the distillate strips the water of mineral salts and other minerals, but it may contain harmful organic matter. The absence of mineral salts (in particular, potassium salts) also does not make such water healthy.
It is reliably known that regular consumption of distilled water has an adverse effect on health, disrupting water-salt metabolism in the human body. Distilled water, among other things, is tasteless, inferior and does not quench thirst at all.
Do you think it's safe to drink tap water? Many will call this question rhetorical, and they will be right, since even children know that tap water should not be drunk. But you have no idea how dangerous tap water can be.
The use of chlorine in the disinfection of drinking water was one of the major breakthroughs of the 20th century, this discovery significantly reduced mortality from infections that were contained in drinking water.
But at that moment, no one thought that when chlorine and other disinfectants react with microorganisms that are present in water, new chemical compounds are formed, and they are very dangerous.
Chlorine is added to tap water for disinfection. Even if you don’t smell bleach, it’s still present in the water, it’s just that now in Moscow and other major cities For disinfection, a less toxic reagent is used - sodium hypochlorite. It is impossible without it, otherwise the pipeline will simply be teeming with bacteria.
As you know, any water from reservoirs contains organic matter (bacteria, viruses, fungi). To make water safe, water treatment plants purify it using various methods.
The most effective water purifier is chlorine and ozone. 99% of bacteria die when combined with chlorine (Cl) or ozone (O3). Ozonation of water is the safest and effective way water purification. The advantage of ozone is that, when added to water, it is quickly destroyed and does not remain in the water, which is why it began to be used at water treatment stations. But another problem arises: how to deliver clean purified water to the consumer through dirty, worn-out pipes?
This is where chlorine comes to the rescue. Water containing a disinfectant in the form of sodium hypochlorite prevents bacteria that live on the walls of pipes from penetrating into the water; once bacteria enter chlorinated water, they die. But then it appears new problem. When chlorine combines with organic matter, byproducts are formed - various types organochlorine substances, and they, in turn, are extremely dangerous because they are toxic to our body.
There are several types of organochlorines that transform into one another depending on water temperature and other factors.
The most toxic compounds - chloroform, trihalomethane (THM) and others - can cause problems over the years for those suffering from respiratory diseases, gastrointestinal tract and genitourinary system.
Large organic compounds, which are 90% carcinogenic, are especially dangerous for humans, that is, they cause cancer.
Russian and American scientists, after conducting special studies, believe that these dangerous compounds or mutagens cause bladder and intestinal cancer in 7 people out of 100,000 who regularly drink chlorinated water.
Many factors influence the formation and quantity of disinfection byproducts. These include the characteristics of the water in a particular area, the amount of organic substances that are initially present in the water, even the temperature of the water matters. And, of course, the type of disinfectant has an effect chemicals and stages of the purification process.
The level will be higher if the chlorine interacts with organic matter in the water long enough. Therefore, higher levels of chloroform are recorded in homes that are far from a water treatment plant than in structures located nearby.
The level of organochlorine substances is also affected by the season - in summer and autumn the water contains more organic substances.
Pipes where bacteria live
No matter how much one would like to believe that chlorine killed everything living and harmful in the water, this is not so. Before reaching your apartment, water passes through kilometers of rusty pipes. Want to make sure there are bacteria in your water pipes? Just try to stick your finger inside the faucet, and you will feel the mucus - these are the very microorganisms.
Of course, chlorine kills most of the microbes living in pipes, but it cannot cope with all microorganisms, since in order to clean pipes of organic matter, shock doses of chlorine are needed, as well as acids and alkalis, but, of course, no one will poison us bleach and especially acid.
Other methods are also used to purify water - for example, ozonation and ultraviolet light. But they do not exclude the use of chlorine (since they do not have a sufficient disinfecting effect), and, therefore, do not protect against the formation of disinfection by-products. In Russia, all stations that use ozonation of drinking water additionally use chlorination. Reports on the safety of tap water are increasingly appearing in the media. In this way, the state seeks to calm already restless citizens, while keeping silent about problems. After all, on one side of the scale is the danger of an epidemic and infection of the population with viruses and bacteria if the water is not chlorinated, and on the other is the danger of developing cancer in a certain relatively small percentage of consumers. Choose the lesser of two evils. This problem exists not only in Russia; in the USA, back in the 70s, hundreds of studies were carried out at institutes studying cancer, which were the first to sound the alarm about the dangers of water chlorination.
Tap water causes cancer in rodents and more
In 1976, the National Institute of Cancer Research in the United States published data showing that chloroform and chlorination byproducts cause cancer in rodents. It was later proven that disinfection byproducts caused by the presence of chlorine in drinking water cause other diseases.
Special animal studies have established that disinfection byproducts present in drinking water cause reproductive problems.
Since the ongoing research revealed only a weak connection between problems of reproductive function and the use of chlorinated tap water, the problem continued to be studied without particularly publicizing it, limiting itself only to publications in specialized literature for scientists and oncologists. But when it comes to cancer and diseases of the reproductive organs, even a small risk can lead to serious consequences.
Why is tap water dangerous for children?
Tap water is also dangerous for children. It does not meet the requirements for drinking water and exceeds some indicators by 10 times, for example, for magnesium - 2 times, for calcium - 3 times, for fluorine - 2-3 times, and for iodine - 20 times.
Studies have shown that disinfection by-products are dangerous for children already during intrauterine development. During the monitoring, the following data was obtained.
In Italy, newborns whose mothers drank chlorinated water during pregnancy had small stature and skull circumference at birth.
In the US state of Iowa, a link was found between intrauterine growth retardation and women's consumption of chlorinated tap water during pregnancy.
Various studies have identified other factors. For example, it has been proven that the frequency of miscarriages is associated with the THM content in the water that a woman drank during pregnancy. Drinking water containing high levels of THMs increases the risk of stillbirth.
Scientists from the National Center for Birth and Developmental Defects in the United States have established a link between THM levels in drinking water and birth defects in children, in particular neural tube defects.
Why is everyone silent
No one says out loud that chlorinated water is dangerous. Why? No other method of water purification has yet been invented. Moreover, in large cities of Russia there are “Clean Water” and other similar campaigns, and under this slogan several kilometers of water pipes are replaced. But it is necessary to change the entire system of existing pipelines, which have been in operation since Soviet times in all cities, and these are thousands and millions of kilometers of old rusty pipes. It is clear that the municipal authorities do not have that kind of money, so everyone is stubbornly silent about the problem, and simply chlorinate the water, in the hope that such cleaning will protect against epidemics and mass diseases. And, of course, no one says that drinking tap water is associated with the occurrence of malignant neoplasms.
We must admit that not everyone can afford to buy bottled water. What can you do to reduce the risk of health problems from tap water?
Some install filters on drinking water taps and purchase filter jugs in the hope of purifying the water from harmful substances, but the use of household filters does not provide clean drinking water.
We have already written about the shortcomings of each a separate type filters. Once again briefly, why filters should be treated with caution.
Almost all filters are based on carbon cassettes and inserts. After 3-5 days of using such filters, their surface is covered with a layer of filtered substances - suspended dust and organochlorines. Room temperature promotes the proliferation of bacteria and microorganisms in such an environment; they can at any time get into the water, which is considered purified. Filter manufacturers do not consider it necessary to inform customers about this fact; it is clear that such information will not arouse the desire to purchase their products. They also don’t say that carbon inserts and cassettes need to be changed regularly, much more often than the manufacturer recommends, since the carbon becomes clogged and loses its cleaning ability. As a rule, none of the consumers do this.
Water obtained as a result of purification using reverse osmosis is also not safe. As a result of such purification, the water becomes practically distilled, its pH level decreases, and it differs significantly in its chemical composition from natural water. But main reason, according to which it is not recommended to drink drinking water purified by reverse osmosis - direct harm to the body. Natural water contains easily digestible calcium, magnesium, and 20 other equally important substances. In water they are in the most bioavailable form for the body. With the constant use of reverse osmosis water, noticeable changes occur - teeth crumble and fall out, skin and hair suffer, and less noticeable changes also occur with internal organs, immunity decreases.
It has been scientifically proven that distilled water leaches calcium from bones and teeth, can unbalance the functioning of the body, and is not suitable for daily use. For example, astronauts on the ISS, having only distilled water at their disposal, artificially saturate it useful minerals to maintain your health. The astronauts have no other choice. Recently, manufacturers of reverse osmosis filters have begun to offer additional flow-through mineralizers for condensing water with calcium and magnesium, but as studies of such water have shown, this is more of a marketing ploy than the truth. Filter sellers are active on the Internet, convincing people to buy their filters, showing electrolysis tricks at home, and supposedly debunking myths about filters. There is only one way out - not to believe the “revelations” and filter the information received.
So why does everyone use filters?
Human nature is designed in such a way that we need a feeling of security. Let it be illusory, illusory, but safe. A fence at the dacha does not in any way protect against robbers, but it is installed because it creates a feeling of security. iron door with three locks it will be useless if there is a window nearby and so on. Also with filters, the consumer trusts advertising, does not delve into all the details and acts on the set-it-and-forget-it principle, and things won’t get any worse.
There are, of course, effective filtration systems. For example, columns with coal bed and a three-way automatic valve for backwashing. But the cost of such columns will be well over 2 thousand euros, which is beyond the means of most consumers, and they take up a lot of space. IN ordinary apartment There is simply nowhere to put such an installation, especially since, as a rule, one column is not enough; manufacturers recommend industrial multi-stage purification and for this they install three or more columns plus micron filters and ultraviolet units.
Everyone's social responsibility. What can you do to reduce the risk of drinking chlorinated water?
The situation with the disinfection of drinking water is of serious concern throughout the world. WHO has developed a number of regulatory documents that indicate the need to control the content of by-product organochlorine compounds in treated water and recommends timely measures to reduce their concentration.
You yourself can take some steps to change the situation and protect yourself, your family and friends.
Find out how water is treated in your area by sending a written request to your local water utility.
Ask representatives of the water utility a question: have tests been done to determine the content of disinfection by-products in drinking water? If not, try to get research done.
Tell your friends and acquaintances what chlorination of water leads to. Encourage them not to drink chlorinated tap water and to reduce shower time to avoid prolonged exposure to chlorinated water and inhalation of fumes.
Water is the most abundant element on Earth, and in our bodies too. Let's figure out what you drink, buy or filter every day. All questions are answered by the head of the artesian water laboratory, Chernova E.I.
Natural or purified?
Artesian water is taken from a well. Tap water - from natural reservoirs and then purified.
The mineralization of artesian water is much higher than tap water, so when boiled it sometimes produces sediment.
Experts believe that artesian water is much healthier. There are no microorganisms or bacteria in it. It is impossible to become infected with anything by consuming it.
Does artesian water require purification?
Quite often, artesian water contains impurities that require filtration. This kind of cleaning is much more easier to clean tap water. And after this, artesian water becomes much more useful.
The most common impurity in artesian water is salt. It accumulated there for thousands of years. This water needs to be filtered.
The filter is selected for each case separately after a water examination. The operation of wells requires significant costs for equipment and cleaning.
Laboratory for the production of artesin water “Khvalovskaya”.
Tap water sources
The water that comes from our tap is taken from natural water sources. They are replenished by precipitation. So the environmental situation in the region directly affects water quality
After collection, the water is filtered and chlorinated. Chlorine negatively affects the gastric mucosa. To remove chlorine from tap water, it is recommended to boil it or leave it in an open container for a while.
However, some chlorine still remains in the water consumed and can be converted into harmful carcinogens. Also, do not forget that the pipeline is not the cleanest place.
Tap water filtration
One of the most popular filters is carbon. It cleans water well from contaminants and chlorine, but is not able to do anything with microbes.
The use of such a filter makes the water cleaner. But do not forget to change the filter on time, otherwise it will not clean, but contaminate the water.
Industrial filters have 5-7 degrees of purification. The water after them will be completely purified, but devoid of all minerals. Bottled water production plants additionally mineralize the water after filtration.
Features of mineral water
Any natural water is mineralized to one degree or another. But not all natural water is safe to drink. And you can’t use medicinal mineral water drink daily.
Mineral water is extracted from aquifers. The deeper the well, the higher the mineralization. Its composition depends on the occurrence of rocks.
Artesian water
Artesian water is called water lying at a depth of 100-1000 meters. Such water does not come into contact with the surface and is not contaminated with impurities. But still, such water must be tested and purified before use.
We distinguish between artesian purified and tap purified water
- The packaging must indicate the production date.
- Drinking water should be free of impurities and sediments
- Company name
- Well number
- Degree of mineralization
- Composition of nutrients
- GOST or TU
For example, Khvalovskaya Premium artesian water is extracted from a depth of 230 meters, purified and bottled near the village of Agalatovo, Leningrad Region.
How to check the composition of the water yourself
There are three standards for water composition:
- GOST RF
- US and EU Standards
GOST is being developed by the Chief Sanitary Doctor of the Russian Federation, in accordance with SanPiN. It means:
- The water is clear and odorless
- pH 7-7.5
- Useful mineralization no more than 1g/l
- There are no or almost no harmful chemical impurities
- Free from bacteria and viruses
Home methods for testing water quality:
Experience with glass
Place a drop of water on the glass. Wait until it dries. White stripes or circles indicate excessive salt content, white coating indicates chlorine.
Experience with a jar
Fill a three-liter jar with water and put it in a dark place for 3 days. If there is sediment, these are salts and impurities. Swamp smell - bacteria. Oil film is a dangerous chemical. components.
Boiling
Fill a saucepan with dark sides with water. Boil the water for 20 minutes. If there is plaque, it is better to purchase an additional filter.
Only a laboratory can make an accurate analysis of the composition of soda. Carefully read the information on the packaging when purchasing water. When in doubt, it is better to change the supplier.
Skin rashes and stains on teeth are the most innocent things that bad tap water can give us. In every region of Russia, tap water has its own disadvantages: it does not hurt citizens to learn more about them.
Text: Ruslan Bazhenov
WITH sulfates
Exceeding the maximum permissible concentration (hereinafter referred to as MPC) of sulfates in drinking water leads to a decrease in the acidity of gastric juice and diarrhea. When the norm is five times higher (MPC - up to 500 mg/l), they accelerate significantly. It is this excess that is typical for tap water in the Rostov, Samara, Kurgan regions and Altai Territory.
In regions with even a twofold excess of sulfates (for example, in Central Asia), the local population gets used to them, while visitors immediately experience “interruptions” in the functioning of the gastrointestinal tract.
Nitrates and nitrites
In the human body, nitrates are reduced to nitrites, and they, in turn, interact with hemoglobin, forming a stable compound - methemoglobin. As you know, hemoglobin carries oxygen, but methemoglobin does not have this ability. As a result, tissues begin to experience oxygen starvation, and a disease develops - nitrate methemoglobinemia. Outbreaks of this disease, mostly among children, have been reported around the world in regions with high levels of nitrates in water. All sick children drank water containing nitrates from 18 to 257 mg/l (in Russia, the maximum permissible concentration for nitrates is 45 mg/l). The content of nitrates in drinking water, three or more times higher than the norm, occurs in the Rostov, Lipetsk, Bryansk, Tula and Voronezh regions.
F torides
For Russia, the problem is exactly the opposite - an excess of fluorine. Studies have shown that when the fluorine content in water is 5-7 mg/l, pronounced osteosclerosis (bone tissue thickening) develops, and at 10-20 mg/l children experience significant
Fluorosis is provided to residents, drinking water with a fluorine content of 2 mg/l, despite the fact that the recommended level of fluoride in drinking water by the World Health Organization (WHO) is 1.5 mg/l. A number of cities and districts of the Moscow, Tver, Penza and Vladimir regions, the Republic of Bashkortostan, Mordovia and the Krasnodar Territory, where the fluoride content in water exceeds the norm, fall into the risk zone. For example, in such cities of the Moscow region as Vidnoye, Podolsk, Yegoryevsk, Odintsovo, Krasnogorsk, fluorosis was detected in 25 percent of the population.
The press, manufacturers of bottled water and fluoride-containing toothpastes willingly exaggerate the alleged problem of lack of fluoride in Russian tap water. But in fact, the amount of fluoride (0.01 mg/l), which, being insufficient, leads to caries, is practically not found in the water sources of our country. This is evidenced by research data from the Gorno-Altaisk state university. To be fair, we would like to add that on the question of how much fluoride is required to prevent caries, the scientific community has not yet reached a consensus.
Iron
Iron in a concentration three times higher than the norm (MPC - 0.3 mg/l) is present in the water supply systems of the Tomsk, Vologda, Tambov, Arkhangelsk, Chelyabinsk, Tver, and Novosibirsk regions. This excess leads to itching, dryness and rashes on the skin; the likelihood of development increases.
Iron of natural origin enters drinking water from underground sources in the central and southern regions of Russia, as well as the Siberian region. In addition, an increased concentration of iron occurs when using steel and cast iron water pipes, which are destroyed due to corrosion. St. Petersburg is especially unfavorable in this regard, where soft water increases corrosion.
Iodine
Sad fact: 65% of the Russian population drinks water with insufficient iodine content. The average iodine consumption in our country is 40-80 micrograms per day per person, which is half the physiological requirement. Lack of iodine leads to the development of Graves' disease, delays in physical and mental health. Water iodization, which they tried to put forward as a countermeasure, turned out to be ineffective, as did iodization of salt.
B rum
The bromine content in the underground springs of the Eastern Trans-Urals exceeds the standards by 40 times (MPC - 0.2 mg/l) - in such concentrations it contributes to the development of pathologies cardiovascular system, . Analysis of statistical data revealed a direct relationship between the overall mortality rate of the population and the bromine content in drinking water in this region.
M arganese
Manganese in concentrations exceeding the norm (maximum concentration limit - 0.1 mg/l) three times is found in tap water in the Tomsk, Vologda, Tambov, Arkhangelsk, Chelyabinsk, Tver, and Novosibirsk regions. A number of scientific studies have found that such an amount of manganese has a negative effect, has a toxic and mutagenic effect on the human body. The manganese content in drinking water directly depends on the activities of nearby industrial enterprises.
Accumulating in brain tissue, mercury leads to severe nerve damage and contributes to disruption of the cardiovascular system. Even small doses are dangerous: the lower limits of mercury content in drinking water, at which it would not accumulate in the body, have not yet been established. One of the main sources (85%) of mercury in environment is the activity of industrial enterprises. Exceeding hygienic standards was revealed in the Belgorod and Vologda regions. However, natural factors also play a role. increased content mercury in the water of some regions, for example in the Altai Mountains.
Lead
Lead is most dangerous for children and pregnant women. In children, it reduces IQ and provokes the development of heart defects. In women, it increases toxicosis and the birth of children with developmental defects, and in addition, leads to infertility.
Exceeding the maximum permissible concentration (norm - 0.03 mg/l) of lead is observed in drinking water in the Kaluga and Ryazan regions. The main source of lead in tap water is the destruction of lead-containing elements of water supply networks (solders, brass alloys).
And aluminum
Has a significant neurotoxic effect causing early attack. In addition, aluminum leaches calcium from the body, which is especially dangerous for a growing body. Exceeding the MPC of aluminum (norm - 0.5 mg/l) was recorded in drinking water in the Arkhangelsk, Samara and Omsk regions. The main source of aluminum in tap water are substances used during water treatment at treatment plants - coagulants.
X loroform
American researchers have established a direct relationship between the content of chloroform in drinking water and the increase in the number of cancer diseases.
During the chlorination of tap water, chloroform is formed, and in fairly high concentrations. WHO sets the maximum permissible concentration for chloroform at 0.03 mg/l, which, according to many researchers, is an outrageous underestimation of the danger of this substance. But the situation is even worse in Russia, where the maximum permissible concentration for chloroform is many times higher than WHO standards - 0.2 mg/l!
Exceeding the maximum permissible concentration of organochlorine compounds was recorded in drinking water in the Kemerovo, Nizhny Novgorod, Perm, Sverdlovsk regions, and St. Petersburg.
P surfactants (surfactants)
They have a lot of negative qualities: from heavy metals; dissolve liquid and solid pollutants, which, if not for surfactants, would settle on the filters; serve as a breeding ground for dangerous microorganisms. An increased level of surfactant content was noted in the rivers: Volga, Oka, Kama, Irtysh, Don, Northern Dvina, Ob, Tom, Tobol, Neva.
