Indicators of organic water pollution. Causes and deadly consequences of water pollution. Integral and comprehensive assessment of water quality

For a long time, the problem of water pollution was not acute for most countries. The available resources were sufficient to meet the needs of the local population. With the growth of industry, the increase in the amount of water used by man, the situation has changed dramatically. Now the issues of its purification and preservation of quality are being dealt with at the international level.

Methods for determining the degree of pollution

Water pollution is commonly understood as a change in its chemical or physical composition, biological characteristics. This defines restrictions on further use of the resource. Pollution deserves more attention fresh water because their purity is inextricably linked to the quality of life and human health.

In order to determine the state of water, a number of indicators are measured. Among them:

chromaticity;
degree of turbidity;
smell;
pH level;
content of heavy metals, trace elements and organic matter;
coli titer;
hydrobiological indicators;
the amount of oxygen dissolved in water;
oxidizability;
the presence of pathogenic microflora;
chemical oxygen demand, etc.

In almost all countries, there are supervisory authorities that must determine the quality from the contents at certain intervals, depending on the degree of importance of a pond, lake, river, etc. If deviations are found, the reasons that could provoke water pollution are identified. Then steps are taken to eliminate them.

What causes resource pollution?

There are many reasons that can cause water pollution. It is not always associated with human activity or industrial enterprises. Natural disasters that occur periodically in different areas can also disrupt environmental conditions. The most common reasons are considered to be:

Domestic and industrial waste water. If they do not pass the synthetic cleaning system, chemical elements and organic substances, then, getting into water bodies, they are capable of provoking a water-environmental catastrophe.
Acid rain. This problem is not talked about so often, so as not to provoke social tension. But the exhaust gases that enter the atmosphere after the emissions of road transport, industrial enterprises, along with rains, end up on the ground, polluting the environment.
Solid waste, which can not only change the state of the biological environment in the reservoir, but also the flow itself. Often this leads to flooding of rivers and lakes, obstruction of the flow.
Organic pollution associated with human activities, natural decomposition of dead animals, plants, etc.
Industrial accidents and man-made disasters.
Floods.
Thermal pollution associated with the production of electricity and other energy. In some cases, water is heated up to 7 degrees, which causes the death of microorganisms, plants and fish, which require a different temperature regime.
Avalanches, mudflows, etc.

In some cases, nature itself is able to clean up over time. water resources. But period chemical reactions will be big. Most often, the death of inhabitants of reservoirs and pollution of fresh water cannot be prevented without human intervention.

The process of moving pollutants in water

If we are not talking about solid waste, then in all other cases, pollutants can exist:

in a dissolved state;
in a balanced state.

They may be droplets or small particles. Biocontaminants are observed in the form of live microorganisms or viruses.

If solid particles get into the water, they will not necessarily settle to the bottom. Depending on the current, storm events, they are able to rise to the surface. An additional factor is the composition of the water. In the sea, it is almost impossible for such particles to sink to the bottom. As a result of the current, they easily move over long distances.

Experts draw attention to the fact that due to the change in the direction of the current in coastal areas, the level of pollution is traditionally higher.

Regardless of the type of pollutant, it can enter the body of fish that live in a reservoir, or birds that are looking for food in the water. If this does not lead to the direct death of the creature, then it can affect the further food chain. There is a high probability that this is how water pollution poisons people and worsens their health.

The main results of the impact of pollution on the environment

Regardless of whether the pollutant enters the body of a person, fish, animal, a protective reaction is triggered. Some types of toxins can be neutralized by immune cells. In most cases, a living organism needs help in the form of treatment so that the processes do not become serious and do not lead to death.

Scientists determine, depending on the source of pollution and its influence, the following indicators of poisoning:

Genotoxicity. Heavy metals and other trace elements are ways to damage and change the structure of DNA. As a result, serious problems are observed in the development of a living organism, the risk of diseases increases, etc.
Carcinogenicity. The problems of oncology are closely related to what kind of water a person or animals consumes. The danger lies in the fact that a cell, having turned into a cancer cell, is able to quickly regenerate the rest in the body.
neurotoxicity. Many metals, chemicals can affect nervous system. Everyone knows the phenomenon of the release of whales, which is provoked by such pollution. The behavior of sea and river inhabitants becomes inadequate. They are not only able to kill themselves, but also begin to devour those who were previously uninteresting to them. Getting into the human body with water or food from such fish and animals, chemicals can provoke a slowdown in the reaction of the brain, destruction of nerve cells, etc.
Violation of energy exchange. By acting on mitochondrial cells, pollutants are able to change the processes of energy production. As a result, the body ceases to carry out active actions. Lack of energy can cause death.
reproductive insufficiency. If water pollution causes the death of living organisms not so often, then it can affect the state of health in 100 percent of cases. Scientists are especially concerned that their ability to reproduce a new generation is being lost. Solving this genetic problem is not easy. Requires artificial renewal of the aquatic environment.

How does water control and treatment work?

Realizing that pollution of fresh water endangers human existence, government agencies at the national and international level create requirements for the implementation of enterprises and people's behavior. These frameworks are reflected in the documents regulating the procedures for water control and the operation of purification systems.

There are the following cleaning methods:

Mechanical or primary. Its task is to prevent large objects from entering the reservoirs. To do this, special gratings and filters are installed on the pipes through which the drains go. It is required to clean the pipes in a timely manner, otherwise the blockage can cause an accident.
Specialized. Designed to capture pollutants of a single type. For example, there are traps for fats, oil slicks, flocs, which are deposited with the help of coagulants.
Chemical. It implies that wastewater will be reused in a closed cycle. Therefore, knowing their composition at the outlet, they select chemicals that are able to return water to its original state. Usually this is technical water, not drinking water.
Tertiary cleaning. So that water can be used in everyday life, agriculture, Food Industry, its quality must be impeccable. To do this, it is treated with special compounds or powders that are capable of retaining heavy metals, harmful microorganisms and other substances in the process of multi-stage filtration.

In everyday life, more and more people are trying to install powerful filters that eliminate pollution caused by old communications and pipes.

Diseases that dirty water can provoke

Until it became clear that pathogens and bacteria can enter the body with water, humanity was faced with global issues. After all, epidemics observed periodically in a particular country claimed the lives of hundreds of thousands of people.

The most common diseases that can lead to bad water, relate:

cholera;
enterovirus;
giardiasis;
schistosomiasis;
amoebiasis;
congenital deformities;
mental anomalies;
intestinal disorders;
gastritis;
skin lesions;
mucous burns;
oncological diseases;
decrease in reproductive function;
endocrine disorders.

The purchase of bottled water and the installation of filters is a means of preventing diseases. Some use silver items, which also partially disinfect the water.

Water pollution has the power to change the planet and make the quality of life completely different. That is why the issue of water conservation is constantly raised. environmental organizations and research centers. This makes it possible to draw the attention of enterprises, the public, and government agencies to existing problems and stimulate the start of active actions to prevent a catastrophe.

Toxic emissions into the environment are so massive that pollution of water sources has become natural. Harmful substances from industrial enterprises, waste Agriculture, organic compounds, household waste. Indicators of water pollution make it possible to judge the nature and extent of the danger threatening humanity, wildlife and the environment as a whole.

Chemical and bacteriological indicators

Chemical and bacteriological quantities are used to assess the quality of water resources. In sanitary practice, the first group includes:

BOD. biological oxygen demand.
COD. Chemical oxygen demand.
The amount of dissolved oxygen.
Oxidability.

COD in this list is the main value by which the quality of the liquid is determined. COD is indicated in milligrams of oxygen spent on the oxidation of organic substances in 1 dm 3 of water. According to sanitary standards, it should not exceed 8 mg O / dm 3.

Bacteriological indicators include:

Microbial number (the number of colonies in 1 ml of liquid).
Coli-titer (the smallest volume of liquid in which 1 coli).
Coli index (an indicator of the number of rod-shaped bacteria in 1 liter).

The microbial number indicates the contamination of the water source with saprophytes. The lower the percentage in the sample, the safer the water in epidemiological terms.

Particular attention is paid to the detection of E. coli excreted by human and animal feces. Fresh fecal contamination is determined by the presence and count of all representatives of the microorganism in the water. Gram-negative bacteria of this type provoke various diseases and infections. Through the analysis of water sources, infection with pathogenic microorganisms can be prevented.

organic pollution

Chemical indicators of water pollution by organic substances - nitrogen-containing components. They judge the quality of the resource. Nitrates and ammonia are a sign of periodic discharge of waste into a water source, nitrites - a source of contamination appeared relatively recently.

The root cause of contamination with organic substances are the corpses of animals, organic compounds in the composition of the soil, the discharge of waste from industrial sites, detergents, factory stocks.

Drinking water quality

According to WHO, drinking water contains 13,000 potentially hazardous substances. Among them are salts of heavy metals, organic residues, pesticides. Pollution of drinking water provokes 80% of diseases from which 25 million people die every year. There is only 1% of water left on the planet that can be consumed without prior purification, and humanity itself is to blame for this. According to the UN organization UNICEF and WHO, 800 million people on Earth (of which 40% are Africans) still use polluted water sources.

INDICATORS OF WATER POLLUTION

INDICATORS OF WATER POLLUTION indicators that determine the degree and nature of water pollution. There are physical indicators (degree of turbidity, smell and pH of water), chemical (the amount of oxygen dissolved in water, MIC, COD, oxidizability, the amount of ammonium nitrogen), bacteriological (E. coli titer and the presence of pathogenic microorganisms), hydrobiological (species composition hydrobionts- the ratio of saprobic and oligosaprobic organisms), etc. In sanitary and biological terms, some hydrobionts are taken into account, mainly bacteria, for example, Escherichia coli (indicators of the presence of human and animal secretions), as well as microorganismsgrowing on oil and oil products (indicators of pollution oil), sanitary-chemical - BOD 5 and COD. Biochemical Pollution Index (BPI) is the ratio of BOD for five days to water oxidizability, expressed as a percentage. BPZ, or coefficient of instability of organic matter dissolved in water, is taken as an indicator of water pollution by organic matter introduced into a reservoir or originated in it. In polluted reservoirs, the BPZ reaches 100-500%.

Ecological encyclopedic dictionary. - Chisinau: Main edition of the Moldavian Soviet Encyclopedia. I.I. Grandpa. 1989

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TOXICITY INDICATORS

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Natural water has a slightly alkaline reaction (6.0-9.0). An increase in alkalinity indicates pollution or blooming of the reservoir. The acidic reaction of water is noted in the presence of humic substances or the penetration of industrial Wastewater.

Rigidity. The hardness of water depends on chemical composition the soil through which water passes, the content of carbon monoxide in it, the degree of pollution by its organic substances. It is measured either in mg-eq / l, or in degrees. According to the degree of hardness, water is: soft (up to 3 mg-eq / l); medium hardness (7mg=eq/L); hard (14mg=eq/l); very hard (over 14 mg-eq/L). Very hard water has an unpleasant taste and can worsen the course of kidney stones.

The oxidizability of water is the amount of oxygen in milligrams that is consumed in the chemical oxidation of e organic and inorganic substances contained in 1 liter of water. Increased oxidizability may indicate water pollution.

Sulfates in amounts exceeding 500 mg/l give the water a bitter-salty taste, at a concentration of 1000-1500 mg/l adversely affect gastric secretion and can cause dyspepsia. Sulphates can be an indicator of pollution of surface waters by animal waste.

The increased content of iron causes coloring, turbidity, gives the water the smell of hydrogen sulfide, an unpleasant inky taste, and in combination with ms humic compounds - a swampy taste.

Ammonia in water is regarded as an indicator of epidemiologically dangerous fresh water pollution with organic substances of animal origin. An indicator of older pollution are salts of nitrous acid - nitrates, which are the products of ammonia oxidation under the influence of microorganisms in the process of nitrification. . However, the content of all three components in water - ammonia, nitrites and nitrates - indicates the incompleteness of the mineralization process and epidemiologically dangerous water pollution.

52. Methods for improving water quality .

I.Basic Methods

1. Lightening and bleaching (cleaning): sedimentation, filtration, coagulation.

2. Disinfection: boiling, chlorination, ozonation, irradiation with UV rays, the use of the oligodynamic action of silver, the use of ultrasound, the use of gamma rays.

II. Special treatment methods: deodorization, degassing, iron removal, softening, desalination, defluorination, fluorination, decontamination.

At the first stage of water purification from an open water source, it is clarified and discolored. Under clarification and discoloration is meant the removal of suspended solids and colored colloids (mainly humic substances) from water and is achieved by sedimentation, filtration. These processes are slow and the bleaching efficiency is low. The desire to accelerate the sedimentation of suspended particles, to speed up the filtration process led to the preliminary coagulation of water chemicals(coagulants) that form hydroxides with rapidly settling flakes and accelerate the settling of suspended particles.

Aluminum sulphate - Al2(SO4)3 is used as coagulants; ferric chloride - FeCl3; ferrous sulphate - FeSO4, etc. Coagulants with properly performed water treatment are harmless to the body, since the residual amounts of aluminum and iron are very small (aluminum - 1.5 mg / l, iron - 0.5 - 1.0 mg / l).

After coagulation and settling, the water is filtered on fast or slow filters.

For any scheme final stage water treatment at the water treatment plant should be disinfected. Its task is the destruction of pathogenic microorganisms, i.e. ensuring epidemic water safety. Disinfection can be carried out by chemical and physical (reagentless) methods.

Boiling is a simple and reliable method. Vegetative microorganisms die when heated to 800C in 20-40 seconds, therefore, at the moment of boiling, the water is actually disinfected.

Ultrasound is used to disinfect domestic wastewater. It is effective against all microorganisms, including spore forms, and its use does not lead to foaming when disinfecting domestic wastewater.

Gamma rays are very reliable and effective method, instantly destroying all types of microorganisms.

Ozone is one of the reagents that do not change the chemical composition of water during disinfection.

Currently, the main method used for water disinfection at waterworks due to technical and economic reasons is the chlorination method.

The effectiveness of water disinfection depends on the selected dose of chlorine, the contact time of active chlorine with water, water temperature and many other factors.

Modifications of chlorination include: double chlorination, chlorination with ammoniation, rechlorination.

The conditioning of the mineral composition of water can be divided into the removal of excess salts or gases from the water (softening, desalination and desalination, iron removal, defluorination, degassing, decontamination, etc.) and the addition minerals in order to improve the organoleptic and physiological properties of water (fluorination, partial mineralization after desalination, etc.).

For the disinfection of individual water supplies, tablet forms containing chlorine are used. Aquasept, tablets containing 4 mg of active chlorine monosodium salt of dichloroisocyanuric acid. Pantocid is a preparation from the group of organic chloramines, solubility is 15-30 minutes. It releases 3 mg of active chlorine.

If the water has an unpleasant odor or a brownish color, organic contamination of the water can be suspected. This can be caused by natural factors or human activities. Regardless of the cause, the presence of organic matter in drinking water can lead to health problems. By what indicators you can determine the degree of water pollution, what it is fraught with for the body and how to purify water - read in our article.

Sources of water pollution

Sources of water pollution with organic substances can be divided into two groups:

sources of natural origin
sources related to human economic activity

The former include organic compounds that make up the soil, as well as those formed during the decomposition of plant and animal residues, etc.

The fact that synthetic organic substances end up in drinking water is a direct result of human activity. The main pollutants are:

enterprise discharges

Of particular danger are oil refineries, factories for the production of fur and leather products, where tannins are used.

fertilizer residues
animal waste
detergents
domestic waste

Water pollution with organic substances also contributes to the reproduction of pathogenic microorganisms there. Therefore, such water is unsuitable for drinking and cooking.

How to determine the amount of organic matter in water?

How can the degree of water pollution by organic substances be determined in the laboratory? Conclusions can be drawn on such an important water quality parameter as chemical oxygen demand (COD). The more oxygen is required for the complete oxidation of organic substances, the greater their concentration in water. That is why it defines COD as one of the main criteria for water quality. There are two more indicators that determine the content of organic substances in water. These are permanganate oxidizability and organic carbon.

If the COD norm is exceeded, then this indicates the unsuitability of water for drinking. When choosing a source of water supply, this indicator is controlled first of all. According to the State Sanitary Standards, COD should not exceed 8 mgO2 / dm3. The higher the COD index, the more oxygen goes to the oxidation of organic matter. Not only vegetation and inhabitants of water bodies suffer from oxygen deficiency. Anaerobic bacteria thrive in an oxygen-free environment, as a result of which toxic hydrogen sulfide is formed from sulfur compounds. ABOUT serious problems with water, the fact of non-compliance of some other indicators in combination with the excess of COD may also indicate.

Oxidability tends to be higher in surface water supplies. And this is not surprising: organic matter of plant origin and organic matter from the soil more easily enter surface sources. Although there are exceptions. For example, groundwater in areas rich in peat has a very high oxidizability.

Impact of organic pollutants on human health

When it comes to water pollution with organic substances, not everyone understands the real danger of such a situation. Of course, if you are told that toxic substances have entered the water, you will immediately begin to sound the alarm. But in fact, the presence of organic substances in drinking water can provoke serious health problems. And non-compliance with the standards for this indicator may indicate, among other things, the presence of harmful chemical compounds.