MPC of cobalt in water. MPC in the aquatic environment

MAXIMUM PERMISSIBLE CONCENTRATION (MPC) OF HARMFUL SUBSTANCES is the maximum concentration of a pollutant that certain time impact 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 from reservoirs, wastewater), and soil.

Limit concentration for working area consider such a concentration of a harmful substance, which at daily work during the entire working period cannot cause disease in the process of work or in the long-term life of the present 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, chemicals 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.

Table 1. MAXIMUM PERMISSIBLE CONCENTRATIONS some gaseous substances in atmospheric air and air of industrial premises
Substance	MPC in atmospheric air, mg / m 3	MPC in the air prod. rooms, mg / m 3
nitrogen dioxide	Maximum single 0.085 Average daily 0.04	2,0
sulphur dioxide	Maximum single 0.5 Average daily 0.05	10,0
carbon monoxide	Maximum single 5.0 Average daily 3.0	During the working day 20.0 Within 60 min.* 50.0 Within 30 minutes* 100.0 Within 15 min.* 200.0
Hydrogen fluoride	Maximum single 0.02 Average daily 0.005	0,05
* Repeated work in conditions of high CO content in the air of the working area can be carried out with a break of at least 2 hours

MPCs are set for the average person, however, people weakened by disease and other factors may feel uncomfortable at concentrations harmful substances, lower 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 individual territories for them, standards for the maximum permissible concentration, reflecting special conditions, can be established.

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 serve as a comparison model. But in large cities, the natural environment is 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

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 Evaluation criteria are given as an example chemical pollution surface water.
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 the 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 of domestic and drinking
cultural and household water use, mg/l
(GN 2.1.5.689-98)

Substances	LPV	MPC
1	2	3
/>Bor	S.-t.	0,5
Bromine	S.-t.	0,2
Bismuth	S.-t.	0,1
Hexachlorobenzene	S.-t.	0,05
Dimethylamine	S.-t.	0,1
Difluorodichloromethane (freon)	S.-t.	10
diethyl ether	Org.	0,3
Iron	Org.	0,3
Isoprene	Org.	0,005
Cadmium	S.-t.	0,001
Karbofos	Org.	0,05
Kerosene:
oxidized	Org.	0,01
Lighting (GOST 4753-68)	Org.	0,05
Technical	Org.	0,001
Acid:
benzoic	Tot.	0,6
Diphenylacetic	Tot.	0,5
oily	Tot.	0,7
Formic	Tot.	3,5
Acetic	Tot.	1,2
Synthetic fatty acids	Tot.	0,1
C5-C20
Manganese	Org.	0,1
Copper	Org.	1
methanol	St.	3
Molybdenum	St.	0,25
Urea	Tot.	1
Naphthalene	Org.	0,01
Oil:
polysulphurous	Org.	0,1
durable	Org.	0,3
Nitrates for:
NO3-	St.	45
NO2-	St.	3,3
Polyethyleneamine	St.	0,1
Thiocyanates	St.	0,1
Mercury	St.	0,0005
Lead	St.	0,03
carbon disulfide	Org.	1
Turpentine	Org.	0,2
Sulfides	Tot.	Absence
Tetraethyl lead	St.	Absence
Tributyl Phosphate	Tot.	0,01

Drinking water at any time of the year should not contain less than 4 g / m of oxygen, and the presence of mineral impurities (mg / l) in it should not exceed: sulfates (SO4 -) - 500; chlorides (Cl -) - 350; iron (Fe2+ + Fe3+) - 0.3; manganese (Mn2+) - 0.1; copper (Cu2+) - 1.0; zinc (Zn2+) - 5.0; aluminum (Al) - 0.5; metaphosphates (PO3 ") - 3.5; phosphates (PO4
3") - 3.5; dry residue - 1000. Thus, water is suitable for drinking if its total mineral content does not exceed 1000 mg / l. Very low mineral content of water (below 1000 mg / l) also worsens its taste, and water , generally devoid of salts (distilled), is harmful to health, since its use disrupts digestion and the activity of endocrine glands.Sometimes, in agreement with the sanitary and epidemiological service, a dry residue content of up to 1500 mg / l is allowed.
Indicators characterizing the pollution of reservoirs and drinking water with substances classified as hazard classes 3 and 4, as well as the physicochemical properties and organoleptic characteristics of water, are additional. They are used to confirm the degree of intensity of anthropogenic pollution of water sources, established by priority indicators.
The application of different criteria for assessing water quality should be based on the advantage of the requirements of the water use whose criteria are more stringent. For example, if a water body simultaneously serves drinking and fisheries purposes, then more stringent requirements (environmental and fisheries) may be imposed on the assessment of water quality.
PCP-10 (indicator of chemical pollution). This indicator is especially important for areas where chemical pollution is observed for several substances at once, each of which many times exceeds the MPC. It is calculated only when identifying areas of environmental emergency and areas of environmental disaster.
The calculation is carried out for ten compounds that maximally exceed the MPC, according to the formula:
PKhZ-10 = C1 / MPC1 + C2 / MPC2 + C3 / MPC3 + ​​... C10 / MPC10,
where Cb C2, C3 ... Cb - concentration chemical substances in water: MPC - fisheries.
When determining PCP-10 for chemicals for which there is no relatively satisfactory value of water pollution, the C/MAC ratio is conditionally taken equal to 1.
To establish PCP-10, it is recommended to analyze water according to the maximum possible number of indicators.
Additional indicators include generally accepted physicochemical and biological characteristics that give a general idea of ​​the composition and quality of waters. These indicators are used to additionally characterize the processes occurring in water bodies. In addition, additional characteristics include indicators that take into account the ability of pollutants to accumulate in bottom sediments and hydrobionts.
The coefficient of bottom accumulation of CDA is calculated by the formula:
KDA \u003d Sd.o. / Sv,
where Sd. about. and Sv - the concentration of pollutants in bottom sediments and water, respectively.
Accumulation coefficient in hydrobionts:
Kn \u003d Sg / Sv,
where Cr is the concentration of pollutants in hydrobionts.
Critical concentrations of chemicals (CC) are determined according to the methodology for determining the critical concentrations of pollutants developed by the State Committee for Hydrometeorology in 1983.
The average CC values ​​of some pollutants are, mg/l: copper - 0.001 ... 0.003; cadmium - 0.008 ... 0.020; zinc - 0.05...0.10; PCB - 0.005; benzo(a)pyrene - 0.005.
When assessing the state of aquatic ecosystems, sufficiently reliable indicators are the characteristics of the state and development of all environmental groups water community.
When identifying the zones under consideration, indicators are used for bacterio-, phyto-, and zooplankton, as well as for ichthyofauna. In addition, to determine the degree of toxicity of waters, an integral indicator is used - biotesting (for lower crustaceans). In this case, the corresponding toxicity of the water mass should be observed in all main phases of the hydrological cycle.
The main indicators for phyto- and zooplankton, as well as for zoobenthos, were taken on the basis of data regional services hydrobiological control characterizing the degree of ecological degradation of freshwater ecosystems.
The parameters of the indicators proposed for the allocation of zones in a given territory should be formed on the basis of materials of sufficiently long observations (at least three years).
It should be borne in mind that the indicator values ​​of species may be different in different climatic zones.
When assessing the state of aquatic ecosystems, indicators of ichthyofauna are important, especially for unique, specially protected water bodies and reservoirs of the first and highest fishery category.
BOD - biological oxygen demand - the amount of oxygen used in biochemical processes of oxidation of organic substances (excluding nitrification processes) for a certain time of sample incubation (2, 5, 20, 120 days), mg O2 / l of water (BODp - for 20 days, BOD5 - for 5 days).
The oxidative process under these conditions is carried out by microorganisms that use organic components as food. The BOD method is as follows. After a two-hour settling, the investigated waste water is diluted with clean water, taken in such an amount that the oxygen contained in it is enough to completely oxidize all organic substances in the waste water. Having determined the content of dissolved oxygen in the resulting mixture, it is left in a closed bottle for 2, 3, 5, 10, 15 days, determining the oxygen content after each of the listed time periods (incubation period). The decrease in the amount of oxygen in water shows how much of it was spent during this time on the oxidation of organic substances in the wastewater. This amount, related to 1 liter of waste water, is an indicator of biochemical oxygen consumption. sewage for a given period of time (BOD2, BODz, BOD5, BODcu, BOD15).
It should be noted that biochemical oxygen consumption does not include its consumption for nitrification. Therefore, a complete BOD should be carried out before the start of nitrification, which usually begins after 15-20 days. The BOD of wastewater is calculated using the formula:
BOD = [(a1 ~ b1) ~ (a2 ~ b2)] X 1000
V'
where ai is the oxygen concentration in the sample prepared for determination at the beginning of incubation (on the “zero day”), mg/l; а2 - oxygen concentration in the diluting water at the beginning of incubation, mg/l; b1 - oxygen concentration in the sample at the end of incubation, mg/l; b2 is the oxygen concentration in the dilution water at the end of incubation, mg/l; V is the volume of waste water contained in 1 liter of the sample after all dilutions, ml.
COD is the chemical oxygen demand determined by the bichromate method, i.e. the amount of oxygen equivalent to the amount of consumed oxidant required for the oxidation of all reducing agents contained in water, mg O2/l of water.
Chemical oxygen consumption, expressed as the number of milligrams of oxygen per 1 liter of wastewater, is calculated by the formula:
HPC - 8(a - b)x N1000
V'
where a is the volume of Mohr's salt solution used for titration in a blank experiment, ml; b is the volume of the same solution used for sample titration, ml; N is the normality of the titrated solution of Mohr's salt; V is the volume of analyzed waste water, ml; 8 - oxygen equivalent.
In relation to BODp/COD, the efficiency of biochemical oxidation of substances is judged.

Vladimir Khomutko

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The problem of the presence of oil products in water and how to deal with it

Among the most common and toxically hazardous substances that serve as sources of pollution of the natural aquatic environment, experts include petroleum products (NP).

Oil and its derivatives are unstable mixtures of hydrocarbons of the saturated and unsaturated groups, as well as their derivatives different kind. Hydrochemistry conventionally interprets the concept of "petroleum products", limited only to their hydrocarbon aliphatic, aromatic and acyclic fractions, which make up the main and most common part of the oil and its components released during oil refining. To denote the content of oil products in water, in international practice there is the term Hydrocarbon Oil Index (“hydrocarbon oil index”).

The maximum permissible concentration (MPC) in water of oil and oil products for cultural and domestic and household water use facilities is at around 0.3 milligrams per cubic decimeter, and for fishery water use facilities - 0.05 milligrams per cubic decimeter.

The determination of oil products contained in water is possible using various instruments and methods, which we will briefly discuss in this article.

To date, there are four main methods for determining the concentration of oil and its derivatives in water, which are based on different physical properties determined oil products:

• gravimetry method;
• IR spectrophotometry;
• fluorimetric method;
• gas chromatography technique.

The methodology for applying one or another method of measuring the content of oils and oil products in water, as well as MPC standards for various kinds petroleum products, is regulated by environmental regulations of federal significance (abbreviated as PND F).

gravimetric method

Its use is regulated by PND F number 14.1:2.116-97.

Its essence is the extraction (dehydration) of oil products from samples provided for analysis using an organic solvent, followed by separation from polar compounds using column chromatography on aluminum oxide of other classes of compounds, after which the content of the substance in water is quantified.

In wastewater studies, this method is used at concentrations ranging from 0.30 to 50.0 milligrams per cubic decimeter, which does not allow determining the compliance of water with MPC standards at fisheries water use facilities.

Another significant disadvantage of this method is a long period the time it takes to take measurements. Therefore, it is not used in the current technological control in production, as well as in other cases where the speed of obtaining results is of paramount importance.

Experts attribute the absence of standard calibrations for samples, which are typical for other methods of analysis, to the advantages of this technique.

The error when using this method with a P value of 0.95 (±δ, %) in the analysis of natural waters varies from 25 to 28 percent, and in the analysis of waste water - from 10 to 35.

IR spectrophotometry

The use of this technique is regulated by PND F number 14.1: 2: 4.168, as well as guidelines MUK 4.1.1013-01.

The essence of this technique for determining the content of oil products in water is the isolation of dissolved and emulsified oil contaminants by extracting them with carbon tetrachloride, followed by chromatographic separation of the oil product from other compounds. organic group, on a column filled with aluminum oxide. After that, the determination of the amount of NP in water is carried out according to the intensity of absorption in the infrared region of the spectrum of C-H bonds.

Infrared spectroscopy is currently one of the most powerful analytical techniques, and is widely used in both applied and fundamental research. Its application is also possible for the needs of the current control of the production process.

The most popular technique for such spectral IR analysis today is Fourier IR. Spectrometers based on this technique, even those in the lower and middle price niche, already compete with traditional instruments such as diffraction spectrometers in terms of their parameters. They are now widely used in numerous analytical laboratories.

In addition to optics, the standard package of such devices necessarily includes a control computer, which not only performs the function of controlling the process of obtaining the required spectrum, but also serves for operational processing of the received data. Using such IR spectrometers, it is quite easy to obtain the vibrational spectrum of the compound presented for analysis.

The main advantages of this technique are:

• small quantities of initial samples of analyzed water (from 200 tons to 250 milliliters);
• high sensitivity of the method (determination step - 0.02 milligrams per cubic decimeter, which allows you to determine the compliance of the results with the MPC standards for fishery reservoirs).

The most important disadvantage of this method of analysis (especially when using a photocolorimetric end), experts call a high degree of its dependence on the type of oil product being analyzed. Determination with a photocolorimeter requires the construction of separate calibration curves for each type of oil product. This is due to the fact that the discrepancy between the standard and the analyzed oil product significantly distorts the results.

This method is used at NP concentrations from 0.02 to 10 milligrams per cubic decimeter. The measurement error at P equal to 0.95 (±δ,%) ranges from 25 to 50 percent.

It is regulated by PND F under the number 14.1: 2: 4.128-98.

The essence of this technique is the dehydration of petroleum products, followed by their extraction from water with hexane, then purification of the resulting extract (if necessary) and subsequent measurement of the fluorescent intensity of the extract, which arises from optical excitation. To measure the intensity of fluorescence, a Fluorat-2 liquid analyzer is used.

The undoubted advantages of this method include:

Aromatic hydrocarbons require different conditions for the excitation and subsequent registration of fluorescent radiation. Experts note the dependence of spectral changes in fluorescence on the wavelength possessed by the exciting light. If excitation occurs in the near part of the ultraviolet spectrum, and even more so in its visible region, then fluorescence appears only in polynuclear hydrocarbons.

Since their share is quite small and directly depends on the nature of the studied oil product, there is a high degree of dependence of the obtained analytical signal on a specific type of oil product. When exposed to ultraviolet radiation, only some hydrocarbons luminesce, mainly high molecular weight aromatic hydrocarbons from the group of polycyclic hydrocarbons. Moreover, the intensity of their radiation varies greatly.

In this regard, in order to obtain reliable results, it is necessary to have a standard solution that contains the same luminescent components (and in the same relative proportions) that are present in the analyzed sample. This is most often difficult to achieve, so the fluorimetric method for determining the content of oil products in water, which is based on recording the intensity of fluorescent radiation in the visible part of the spectrum, is unsuitable for mass analyzes.

This method can be applied at oil concentrations ranging from 0.005 to 50.0 milligrams per cubic decimeter.

The error of the results obtained (at P equal to 0.95, (±δ, %)) ranges from 25 to 50 percent.

The use of this technique is regulated by GOST No. 31953-2012.

This technique is used to determine the mass concentration of various petroleum products both in drinking (including packaged in containers) and in natural (both surface and underground) water, as well as in water contained in household and drinking sources. This method is also effective in the analysis of waste water. The main thing is that the mass concentration of oil products should not be less than 0.02 milligrams per cubic decimeter.

The essence of the gas chromatography method is the extraction of NP from the analyzed water sample using an extractant, its subsequent purification from polar compounds using a sorbent, and the final analysis of the resulting substance on a gas chromatograph.

The result is obtained after summing up the areas of the chromatographic peaks of the released hydrocarbons and by subsequent calculation of the NP content in the analyzed water sample using a predetermined calibration dependence.

With the help of gas chromatography, not only the total concentration of oil products in water is determined, but also their specific composition is identified.

Gas chromatography is generally a technique based on the separation of thermostable volatile compounds. Approximately five percent of total number known to science organic compounds. However, they occupy 70-80 percent of the total number of compounds used by man in production and everyday life.

The role of the mobile phase in this technique is played by a carrier gas (usually an inert group), which flows through the stationary phase with much larger area surfaces. As the carrier gas of the mobile phase is used:

• hydrogen;
• nitrogen;
• carbon dioxide;
• helium;
• argon.

Most often, the most accessible and inexpensive nitrogen is used.

It is with the help of the carrier gas that the components to be separated are transported through the chromatographic column. In this case, this gas does not interact either with the separated components themselves, or with or with the substance of the stationary phase.

The main advantages of gas chromatography:

• the relative simplicity of the equipment used;
• a fairly wide field of application;
• the possibility of high-precision determination of sufficiently small concentrations of gases in organic compounds;
• the speed of obtaining the results of the analysis;
• a wide range of both used sorbents and substances for stationary phases;
• a high level of flexibility that allows you to change the separation conditions;
• possibility of chemical reactions in a chromatographic detector or in a chromatographic column, which significantly increases the coverage of chemical compounds subjected to analysis;
• increased information content when used with other instrumental methods of analysis (for example, with mass spectrometry and Fourier-IR spectrometry).

The error of the results of this technique (P equals 0.95 (±δ,%)) ranges from 25 to 50 percent.

It should be noted that only the method of measuring the content of oil products in water using gas chromatography is standardized in the international standardization organization, which we all know under the acronym ISO, since only it makes it possible to identify the types of oil and oil product pollution.

Regardless of the methodology used, constant monitoring of the waters used in production and in the domestic sphere is vital. According to environmental specialists, in some Russian regions more than half of all diseases are somehow related to the quality of drinking water.

High concentration of oil products in water

Moreover, according to the same scientists, improving the quality of drinking water alone can extend life by five to seven years. All these factors indicate the importance of constant monitoring of the state of water near the oil industry, which are the main sources of environmental pollution by oil and its derivatives.

Timely detection of exceeding the MPC of oil products in water will allow avoiding large-scale disturbances of the ecosystem, and timely taking the necessary measures to eliminate the current situation.

However, for effective work environmental scientists need governmental support. And not so much in the form of cash subsidies, but in the creation of a regulatory framework that regulates the responsibility of enterprises National economy for violation of environmental standards, as well as in strict control over the implementation of adopted standards.

Chemical properties of water

Oxidability

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

The waters of surface and underground sources have different oxidizability - in groundwater, the oxidizability value is negligible, with the exception of swamp waters and waters oil fields. The oxidation of mountain rivers is lower than that of lowland rivers. 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 different type water use (drinking, fishery, recreational areas) establish 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 has crucial during 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.

Accumulation large quantities 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, the damaging concentrations of ammonium nitrates for various fish species begin with values ​​of the order of hundreds of milligrams per liter.

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 at high concentrations impair the taste of water, and at high concentrations make 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

Sulphates 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 amount of calcium enters natural water bodies with effluents from metallurgical, chemical, glass and silicate industries, as well as with runoff from the surface of farmland 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 for being lightweight silver metal. In natural waters, it is present in residual quantities in the form of ions or insoluble salts. Sources of aluminum entering natural waters are wastewater from 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 plays an important 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 is an alkali metal and a 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 are possible. 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 of chemical reactions, as a food additive.

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.

The high concentration of hydrogen sulfide gives the water its characteristic bad smell(rotten eggs) and toxic properties, 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.

Maximum allowable concentrations of pollutants in water

are regulated by normative documents ensuring the environmental safety of water resources. In the Republic of Belarus, Ukraine and the Russian Federation, at first the standards adopted earlier in the USSR were used, these are:

« Sanitary rules and norms for the protection of surface waters from pollution”, SanPiN 4630-88, Ministry of Health of the USSR, 06/04/1988 and Additions: No. 1 (N 5311-90, dated 12/28/90), No. 2 (N 5793-91 dated 07/11/91), No. 3 (N 6025 -91 dated 10/21/91).2). "" SanPiN 4631-88, Ministry of Health of the USSR, 6.07.1988.3). " Rules for the protection of surface waters”, Goskompriroda of the USSR, dated February 21, 1991, Maximum permissible concentrations of normalized substances in the water of fishery water bodies (represented by the Glavrybvod of the USSR Ministry of Fisheries).

In addition to these regulations, initial period the formation of new states were guided by the Republican Water Codes that were in force in each republic of the USSR. Subsequently, in the Republic of Belarus, Ukraine and the Russian Federation, their legislative acts were developed and approved on the regulation of the maximum permissible concentrations of pollutants in water (MPC) in order to ensure environmental safety reservoirs and water use.

Regulatory framework in the Republic of Belarus:

Water Code of the Republic of Belarus dated April 30, 2014 No. 149-ZAdopted by the House of Representatives on April 2, 2014 Approved by the Council of the Republic on April 11, 2014

Hygienic standards 2.1.5.10-21-2003. Maximum Permissible Concentrations (MPC) of chemicals in the water of water bodies for drinking and domestic water use. Ministry of Health of the Republic of Belarus, Decree of 12. 12. 2003 No. 163.

On some issues of water quality regulation of fishery water bodies. Ministry Decree natural resources and Environment of the Republic of Belarus and the Ministry of Health of the Republic of Belarus No. 43/42 dated May 8, 2007.

Regulatory framework in Ukraine:

Water Code of Ukraine. Resolution of the Verkhovna Rada No. 214/95-VR dated 06.06.95, VVR, 1995, No. 24, art. 190

The maximum permissible concentrations of harmful substances in the water of reservoirs for sanitary and household water use and the requirements for the composition and properties of water in water bodies for drinking and domestic water use are regulated SanPinom 4630-88 and three Additions to these Sanitary Rules and Norms: No. 1 ( N 5311-90, dated 12/28/90), No. 2 ( N 5793-91 dated 07/11/91), No. 3 ( N 6025-91 from 21.10.91).

« Sanitary rules and norms for the protection of coastal waters of the seas from pollution in places of water use of the population» SanPiN 4631-88, Ministry of Health of the USSR, 07/06/1988.

The maximum permissible concentrations of harmful substances in sea water are specified in the Appendix to " Rules for the protection of internal sea ​​waters and territorial seas of Ukraine from pollution and clogging”, approved by the Resolution of the Cabinet of Ministers of Ukraine No. 431 dated March 29, 2002.

Regulatory framework in the Russian Federation:

"Water Code of the Russian Federation" dated 06/03/2006 N 74-FZ (as amended on 11/28/2015) (with amendments and additions that entered into force on 01/01/2016).

SanPiN 2.1.5.980-00"Hygienic requirements for the protection of surface waters". Decree of the Ministry of Health of the Russian Federation of June 22, 2000

Hygienic standards 2.1.5.1315-03"Maximum Permissible Concentrations (MACs) of Chemicals in the Water of Water Bodies for Domestic Drinking and Cultural and Domestic Water Use", Decree of the Ministry of Health of the Russian Federation, 2003 dated April 30, 2003 N 78 (as amended on September 28, 2007)

Order of the Federal Agency for Fisheries dated January 18, 2010 No. #20"On approval of water quality standards for water bodies of fishery significance, including standards for maximum permissible concentrations of harmful substances in the waters of water bodies of fishery significance"

On approval of the Regulations on measures for the conservation of aquatic biological resources and their habitat. Decree No. 380 of the Government of the Russian Federation of April 29, 2013

Table. MPC of some chemicals in water bodies and reservoirs.

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