MPC for drinking water. MPC in water

AT Russian Federation the quality of drinking water must meet certain requirements established by SanPiN 2.1.4.10749-01 "Drinking water". In the European Union (EU), the directive "On the quality of drinking water intended for human consumption" 98/83/EC defines the standards. World Organization(WHO) establishes water quality requirements in the 1992 Guidelines for the Control of Drinking Water Quality. There are also regulations of the Agency for Protection environment United States (U.S.EPA). In the norms there are slight differences in various indicators, but only water of the corresponding chemical composition ensures human health. The presence of inorganic, organic, biological contaminants, as well as an increased content of non-toxic salts in amounts exceeding those specified in the requirements presented, leads to the development of various diseases.
Basic requirements for drinking water are that it should have favorable organoleptic characteristics, be harmless in its chemical composition and safe in epidemiological and radiation terms. Before water is supplied to distribution networks, at water intake points, external and internal water supply networks, the quality of drinking water must comply with hygienic standards.

Table 1. Requirements for the quality of drinking water

s.-t. – sanitary-toxicological; org. – organoleptic.

Chemical properties of water

Oxidability

Oxidability indicates the amount of oxygen in milligrams required for oxidation. organic matter contained in 1 dm³ of water.

The waters of surface and underground sources have different oxidizability - in groundwater the value of oxidizability is insignificant, with the exception of marsh waters and waters of oil fields. Oxidability mountain rivers lower than the plains. The highest value of oxidizability (up to tens of mg/dm³) is found in rivers fed by swamp waters.

The value of oxidizability naturally changes throughout the year. Oxidability is characterized by several values ​​- permanganate, dichromate, iodate oxidizability (depending on which oxidizing agent is used).

MPC oxidizability of water have the following meanings: chemical oxygen demand or bichromate oxidizability (COD) of drinking water bodies should not exceed 15 mg O₂ / dm³. For reservoirs in recreation areas, the COD value should not exceed 30 mg O₂ /dm³.

pH value

The hydrogen index (pH) of natural water shows the quantitative content of carbonic acid and its ions in it.

Sanitary and hygienic standards for reservoirs of various types of water use (drinking, fisheries, recreational zones) are established MPC pH in the range of 6.5-8.5.

The concentration of hydrogen ions, expressed as a pH value, is one of the most important indicators of water quality. The pH value is of decisive importance in the course of numerous chemical and biological processes in natural water. It is the pH value that determines which plants and organisms will develop in a given water, how elements will migrate, and the degree of corrosiveness of water to metal and concrete structures also depends on this value.

The pH value determines the pathways for the conversion of biogenic elements and the degree of toxicity of pollutants.

Hardness of water

The hardness of natural water is manifested due to the content of dissolved calcium and magnesium salts in it. The total content of calcium and magnesium ions is the total hardness. Rigidity can be expressed in several units of measurement; in practice, the value of mg-eq / dm³ is more often used.

High hardness impairs household characteristics and taste properties of water, and has an adverse effect on human health.

MPC for hardness drinking water is normalized by the value of 10.0 mg-eq / dm³.

The technical water of heating systems is subject to more stringent requirements for their rigidity due to the likelihood of scale formation in pipelines.

Ammonia

The presence of ammonia in natural water is due to the decomposition of nitrogen-containing organic substances. If ammonia in water is formed during the decomposition of organic residues (faecal contamination), then such water is unsuitable for drinking. Ammonia is determined in water by the content of ammonium ions NH₄⁺.

MPC for ammonia in water is 2.0 mg/dm³.

Nitrites

Nitrite NO₂⁻ is an intermediate product of the biological oxidation of ammonia to nitrate. Nitrification processes are possible only under aerobic conditions, otherwise natural processes follow the path of denitrification - the reduction of nitrates to nitrogen and ammonia.

Nitrites in surface waters are in the form of nitrite ions, in acidic waters they can partially be in the form of undissociated nitrous acid (HN0₂).

MAC of nitrites in water is 3.3 mg / dm³ (according to the nitrite ion), or 1 mg / dm³ in terms of ammonium nitrogen. For fishery reservoirs, the norms are 0.08 mg / dm³ for nitrite ion or 0.02 mg / dm³ in terms of nitrogen.

Nitrates

Nitrates, compared with other nitrogen compounds, are the least toxic, but in significant concentrations cause harmful effects on organisms. The main danger of nitrates is their ability to accumulate in the body and oxidize there to nitrites and nitrosamines, which are much more toxic and can cause the so-called secondary and tertiary nitrate poisoning.

The accumulation of large amounts of nitrates in the body contributes to the development of methemoglobinemia. Nitrates react with blood hemoglobin and form methemoglobin, which does not carry oxygen and thus causes oxygen starvation of tissues and organs.

The subthreshold concentration of ammonium nitrate, which does not have harmful effects on the sanitary regime of the reservoir, is 10 mg/dm³.

For fishery reservoirs, damaging concentrations of ammonium nitrates for various kinds fish start at values ​​on the order of hundreds of milligrams per litre.

MPC nitrates for drinking water is 45 mg / dm³, for fishery reservoirs - 40 mg / dm³ for nitrates or 9.1 mg / dm³ for nitrogen.

chlorides

Chlorides in high concentration worsen taste qualities water, and at high concentrations make the water unsuitable for drinking purposes. For technical and economic purposes, the content of chlorides is also strictly regulated. Water containing a lot of chlorides is unsuitable for irrigation of agricultural plantations.

MPC chlorides in drinking water should not exceed 350 mg / dm³, in the water of fishery reservoirs - 300 mg / dm³.

sulfates

Sulfates in drinking water worsen its organoleptic characteristics, at high concentrations they have a physiological effect on the human body. Sulfates are used in medicine as a laxative, so their content in drinking water is strictly regulated.

Magnesium sulfate is determined in water by taste at a content of 400 to 600 mg / dm³, calcium sulfate - from 250 to 800 mg / dm³.

MPC sulfates for drinking water - 500 mg / dm³, for waters of fishery reservoirs - 100 mg / dm³.

There is no reliable data on the effect of sulfates on corrosion processes, but it is noted that when the sulfate content in water exceeds 200 mg/dm³, lead is washed out of lead pipes.

Iron

Iron compounds enter natural water from natural and anthropogenic sources. Significant amounts of iron enter water bodies along with wastewater from metallurgical, chemical, textile and agricultural enterprises.

At an iron concentration of more than 2 mg/dm³, the organoleptic properties of water worsen - in particular, an astringent aftertaste appears.

MPC iron in drinking water 0.3 mg / dm³, with limiting hazard indicators - organoleptic. For the waters of fishery reservoirs - 0.1 mg / dm³, the limiting indicator of harmfulness is toxicological.

Fluorine

High concentrations of fluorine are observed in wastewater from glass, metallurgical and chemical industries (in the production of fertilizers, steel, aluminum, etc.), as well as at mining enterprises.

MPC for fluorine in drinking water is 1.5 mg / dm³, with a limiting sanitary-toxicological hazard indicator.

Alkalinity

Alkalinity is the logical opposite of acidity. The alkalinity of natural and industrial waters is the ability of the ions contained in them to neutralize an equivalent amount of strong acids.

Indicators of water alkalinity must be taken into account in the reagent treatment of water, in the processes of water supply, when dosing chemical reagents.

If the concentration of alkaline earth metals is elevated, knowledge of the alkalinity of the water is essential in determining the suitability of the water for irrigation systems.

Water alkalinity and pH are used to calculate the carbonic acid balance and determine the concentration of carbonate ions.

Calcium

The intake of calcium into natural waters comes from natural and anthropogenic sources. A large number of Calcium enters natural water bodies with effluents from metallurgical, chemical, glass and silicate industries, as well as with runoff from the surface of agricultural land where mineral fertilizers were used.

MPC calcium in the water of fishery reservoirs is 180 mg/dm³.

Calcium ions are hardness ions that form hard scale in the presence of sulfates, carbonates and some other ions. Therefore, the calcium content in industrial waters supplying steam power plants is strictly controlled.

The quantitative content of calcium ions in water must be taken into account when studying the carbonate-calcium balance, as well as when analyzing the origin and chemical composition of natural waters.

Aluminum

Aluminum is known as a light silvery metal. In natural waters, it is present in residual quantities in the form of ions or insoluble salts. Sources of aluminum entering natural waters - wastewater metallurgical industries, bauxite processing. In water treatment processes, aluminum compounds are used as coagulants.

Dissolved aluminum compounds are highly toxic, can accumulate in the body and lead to severe damage to the nervous system.

MPC aluminum in drinking water should not exceed 0.5 mg/dm³.

Magnesium

Magnesium is one of the most important biogenic elements that play big role in the life of living organisms.

Anthropogenic sources of magnesium in natural waters - wastewater from metallurgy, textile, silicate industries.

MPC magnesium in drinking water - 40 mg/dm³.

Sodium

Sodium - alkali metal and biogenic element. In small amounts, sodium ions perform important physiological functions in a living organism; in high concentrations, sodium causes disruption of the kidneys.

In wastewater, sodium enters natural waters mainly from irrigated agricultural lands.

MPC sodium in drinking water is 200 mg/dm³.

Manganese

The element manganese is found in nature in the form of mineral compounds, and for living organisms it is a trace element, that is, in small quantities it is necessary for their life.

A significant flow of manganese into natural water bodies occurs with the effluents of metallurgical and chemical enterprises, mining and processing plants and mine production.

MPC of manganese ions in drinking water -0.1 mg / dm³, with a limiting organoleptic hazard indicator.

Excessive intake of manganese in the human body disrupts the metabolism of iron; in case of severe poisoning, serious mental disorders. Manganese is able to gradually accumulate in body tissues, causing specific diseases.

Residual chlorine

Sodium hypochlorite used for water disinfection is present in water in the form of hypochlorous acid or hypochlorite ion. The use of chlorine for the disinfection of drinking and waste water, despite criticism of the method, is still widely used.

Chlorination is also used in the production of paper, cotton wool, for the disinfestation of refrigeration plants.

Active chlorine should not be present in natural reservoirs.

MPC free chlorine in drinking water 0.3 - 0.5 mg/dm³.

Hydrocarbons (petroleum products)

Oil products are one of the most dangerous pollutants of natural water bodies. Petroleum products get into natural waters in several ways: as a result of oil spills during accidents of oil tankers; with wastewater from the oil and gas industry; with wastewater from chemical, metallurgical and other heavy industries; with household waste.

Small amounts of hydrocarbons are formed as a result of the biological decomposition of living organisms.

For sanitary and hygienic control, indicators of the content of dissolved, emulsified and sorbed oil are determined, since each of the listed species affects living organisms in a different way.

Dissolved and emulsified petroleum products have a diverse adverse effect on the plant and animal world reservoirs, on human health, on the general physical and chemical state of biogeocenosis.

MPC for oil products for drinking water -0.3 mg / dm³, with limiting organoleptic hazard indicators. For reservoirs for fishery purposes, MPC for oil products is 0.05 mg/dm³.

Polyphosphates

Polyphosphate salts are used in water treatment processes to soften industrial water, as a component of household chemicals, as a catalyst or inhibitor chemical reactions as a dietary supplement.

MPC for polyphosphates for drinking water - 3.5 mg / dm³, with limiting organoleptic hazard indicators.

Silicon

Silicon is a common element in the earth's crust, it is part of many minerals. For the human body is a trace element.

A significant content of silicon is observed in the wastewater of ceramic, cement, glass and silicate industries, in the production of binders.

MPC silicon in drinking water - 10 mg/dm³.

Sulfides and hydrogen sulfide

Sulfides are sulfur-containing compounds, salts of hydrosulfide acid H₂S. In natural waters, the content of hydrogen sulfide makes it possible to judge organic pollution, since hydrogen sulfide is formed during protein decay.

Anthropogenic sources of hydrogen sulfide and sulfides are household wastewater, wastewater from metallurgical, chemical and pulp industries.

A high concentration of hydrogen sulfide gives the water a characteristic unpleasant odor (rotten eggs) and toxic properties, the water becomes unsuitable for technical and household purposes.

MPC for sulfides - in reservoirs for fishery purposes, the content of hydrogen sulfide and sulfides is unacceptable.

Strontium

Reactive metal, in its natural form, is a trace element of plant and animal organisms.

Increased intake of strontium in the body changes the metabolism of calcium in the body. Perhaps the development of strontium rickets or "Urov's disease", in which growth retardation and curvature of the joints are observed.

Radioactive isotopes of strontium cause a carcinogenic effect or radiation sickness in humans.

MAC of natural strontium in drinking water is 7 mg / dm³, with a limiting sanitary-toxicological hazard indicator.

PEEP - the maximum permissible concentration of a substance in the water of a reservoir for drinking and domestic water use, mg / l. This concentration should not have a direct or indirect effect on the human body throughout life, as well as on the health of subsequent generations, and should not worsen the hygienic conditions for water use. PEEP.r. - The maximum permissible concentration of a substance in the water of a reservoir used for fishery purposes, mg/l.
The assessment of the quality of aquatic ecosystems is based on normative and directive documents using direct hydrogeochemical assessments. In table. 2.4, as an example, the criteria for assessing the chemical pollution of surface waters are given.
For water, maximum allowable concentrations of more than 960 chemical compounds, which are combined into three groups according to the following limiting indicators of harmfulness (LPV): sanitary-toxicological (s.-t.); general sanitary (gen.); organoleptic (org.).
MPC of some harmful substances in aquatic environment are presented in table. 2.1.4.
The highest requirements are placed on drinking water. State standard on water used for drinking and Food Industry(SanPiN 2.1.4.1074-01), determines the organoleptic indicators of water that are favorable for humans: taste, smell, color, transparency, as well as the harmlessness of its chemical composition and epidemiological safety.
Table 2.1.4
MPC of harmful substances in water bodies household and drinking and
cultural and household water use, mg/l
(GN 2.1.5.689-98)

MAXIMUM PERMISSIBLE CONCENTRATION (MPC) OF HARMFUL SUBSTANCES- this is the maximum concentration of a harmful substance, which for a certain time of exposure does not affect human health and its offspring, as well as the components of the ecosystem and natural community generally.

Many pollutants enter the atmosphere from various industrial productions and vehicles. To control their content in the air, well-defined standardized environmental standards are needed, and therefore the concept of the maximum permissible concentration was introduced. MPC values ​​for air are measured in mg/m 3 . MPCs have been developed not only for air, but also for food products, water (drinking water, water of reservoirs, sewage), soil.

Limit concentration for working area consider such a concentration of a harmful substance that, during daily work during the entire working period, cannot cause disease in the process of work or in the long-term life of this and subsequent generations.

Limit concentrations for atmospheric air are measured in settlements and refer to a specific time period. For air, a maximum single dose and an average daily dose are distinguished.

Depending on the MPC value chemical substances in the air are classified according to the degree of danger. For extremely hazardous substances (mercury vapor, hydrogen sulfide, chlorine) MPC in the air of the working area should not exceed 0.1 mg/m 3 . If the MPC is more than 10 mg/m 3, then the substance is considered to be of low hazard. Examples of such substances include ammonia.

MPCs are set for the average person, however, people weakened by disease and other factors may feel uncomfortable at concentrations of harmful substances that are lower than the MPC. This, for example, applies to heavy smokers.

The values ​​of the maximum permissible concentrations of certain substances in a number of countries differ significantly. Thus, the MPC of hydrogen sulfide in the atmospheric air with a 24-hour exposure in Spain is 0.004 mg/m 3, and in Hungary - 0.15 mg/m 3 (in Russia - 0.008 mg/m 3).

In our country, the standards for the maximum permissible concentration are developed and approved by the sanitary and epidemiological service and state bodies in the field of environmental protection. Environmental quality standards are the same for the entire territory of the Russian Federation. Taking into account natural and climatic features, as well as increased social value separate territories for them, standards of maximum permissible concentration may be established, reflecting special conditions.

With the simultaneous presence in the atmosphere of several harmful substances of unidirectional action, the sum of the ratios of their concentrations to the MPC should not exceed one, but this is far from always the case. According to some estimates, 67% of the Russian population lives in regions where the content of harmful substances in the air is above the established maximum permissible concentration. In 2000, the content of harmful substances in the atmosphere in 40 cities with a total population of about 23 million people from time to time exceeded the maximum permissible concentration by more than ten times.

When assessing the risk of pollution, studies carried out in biosphere reserves. But in major cities natural environment far from ideal. So, according to the content of harmful substances, the Moscow River within the city is considered a “dirty river” and a “very dirty river”. At the exit of the Moskva River from Moscow, the content of oil products is 20 times higher than the maximum permissible concentrations, iron - 5 times, phosphates - 6 times, copper - 40 times, ammonium nitrogen - 10 times. The content of silver, zinc, bismuth, vanadium, nickel, boron, mercury and arsenic in the bottom sediments of the Moskva River exceeds the norm by 10–100 times. Heavy metals and other toxic substances from the water enter the soil (for example, during floods), plants, fish, agricultural products, drinking water, both in Moscow and downstream in the Moscow region.

Chemical methods for assessing the quality of the environment are very important, but they do not provide direct information about the biological hazard of pollutants - this is the task of biological methods. Maximum allowable concentrations are certain standards for the sparing effect of pollutants on human health and the natural environment.

Elena Savinkina