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Abstract

Content

INTRODUCTION

Water management is an integral part of the economy. Its main task is to provide consumers with water in the necessary quantity and quality. In the conditions of the low-water climate of the Donetsk steppe, water supply to the population and enterprises is of strategic importance. The basis of water management is the resources of surface and underground water. Their rational use and protection from pollution and depletion is regulated by legislation and determines the management of water resources as a single mechanism. Of particular importance is the problem of rational use and protection of water resources in the conditions of the low-water region of the Donetsk People's Republic. All waters (water bodies) on the territory of the DPR are the property of the people and can only be transferred for use. Reservoirs are of great importance not only for the life support of the population, industry, agriculture, but also for recreation, tourism, and sports. In the conditions of anthropogenic loads on the natural environment, there is a need to develop and comply with the rules for the use of water resources, their rational use and environmentally directed protection. The subject of this work is the surface waters of Donetsk. The purpose of the work is: to investigate the state and problems of surface waters, to consider the prospects for solving these problems. Tasks of the work: o characterize the characteristics of the water resources of the region; to study the use of water resources in Donetsk; study the problem of water pollution; consider the main directions for improving the state of water resources. To write the work, the following methods were used: literary; cartographic; statistical; comparative; program-target. In this work, numerous sources were used: textbooks and textbooks; statistical materials; reference books; booklets; Internet sites.

1. THE STATE AND RATIONAL USE OF WATER RESOURCES IN THE TERRITORY OF DONETSK

All water bodies of the city of Donetsk and the temporarily annexed territories are objects of national significance. The watershed of the Dnieper basin and the basin of the Azov Sea rivers runs through the territory of the city of Donetsk and the temporarily annexed territories. Of the 120 water bodies of the city and temporarily attached territories, 8 reservoirs and 112 ponds should be allocated. The total area of reservoirs is 864.7 ha, the volume of water resources is 28.1 million cubic meters. Kalmius is the main river that flows through the city center in five districts: Kievsky, Voroshilovsky, Kalininsky, Leninsky and Budennovsky. Its tributaries within the city limits are the Shirokaya, Bogodukhova, Durnaya, Ignatyevskaya, and untitled gullies. On the Kalmius River within the Kiev and Voroshilovsky districts there are two reservoirs – Kalmius and Nizhne-Kalmius. The Gruzskaya River, a left tributary of the Kalmius River, flows within the city of Mospino in the Proletarsky District. The north-western part of the city is divided by gullies and the Osykovaya and Lozovaya rivers (the basin of the Volchya River). Water resources of the rivers and gullies of Donetsk are presented: natural, unregulated surface runoff generated by precipitation and groundwater drainage; wastewater and mine water; regulated runoff-ponds and reservoirs. The main consumers of water resources are mines and enterprises of Donetsk. In the current year, 104 special water users were registered on the state register in Donetsk. In 2019, the total volume of wastewater discharged into surface water bodies amounted to 103.5 million cubic meters, of which 41.1 million cubic meters or 40% of the gross discharge was insufficiently treated. Due to the high anthropogenic and technogenic load for a long time, many water bodies of the city are extremely shallow, have a significant level of bacterial and chemical pollution. Monitoring of water quality in them shows that at different phases of the hydrological regime, the concentrations of pollutants practically do not change, which indicates a loss of the self-cleaning ability of water bodies. The main subjects of the discharge of insufficiently treated wastewater into water bodies on the territory of Donetsk are the existing enterprises of the coal industry: the State Enterprise "Donetsk Coal Energy Company "(the mine named after him). Chelyuskintsev, the mine named after him. Skochinsky – work for coal mining, mine 17-17 bis, mine Abakumov, mine Lidiyevka-work in the mode of drainage) and the State Enterprise "Mine them. Zasyadko" , and DD "Donbassugleavtomatika", which includes including the "Donetsk Directorate on execution of projects of liquidation and preparation for the elimination of mines" (mine them. M. Gorky, Capital mine No. 9, Zaperevalnaya mine No. 2). The results of the water quality study carried out by environmental monitoring subjects indicate deviations of water quality indicators from the accepted sanitary standards for the protection of surface waters from pollution in terms of sulfates, suspended substances, salinity and petroleum products. In the summer, there is an excess of the current norms for the biochemical consumption of oxygen and the enrichment of water with mineral forms of nitrogen, which indicates an increased content of easily oxidized organic substances in the water of surface reservoirs and a significant share of mine water discharges. The quality of the discharged mine water is evaluated according to the standards of water composition and properties provided for by the sanitary rules and norms for the protection of surface water from pollution SanPiN 4630-88 for surface water objects of cultural and domestic water use. Deviations in the quality indicators of mine water discharged into water bodies are mainly noted for dry residue, chlorides, and sulfates. These substances, according to the sanitary classification, are classified as hazard class 4-moderately dangerous substances. Water in surface water bodies located on the territory of Donetsk city does not meet the water quality standards for water bodies of economic and drinking purposes, and, accordingly, is not used for drinking water supply. According to the results of laboratory studies, the water quality of the reservoirs does not meet the sanitary standards for bathing. However, there are reservoirs in the city, which in the summer are spontaneously used by the population for recreation and swimming. The main sources of pollution of reservoirs of Donetsk: discharge of waste water from industrial enterprises with an inefficient treatment system; mine water discharge; leakage of sewers; spontaneous landfills of solid household waste, the arrangement of vegetable gardens within the boundaries of coastal protective strips of reservoirs; storm/surface runoff from urban areas.

2. THE MERCURY CONTENT IN THE WATER BODIES OF DONETSK

Mercury is present in very small amounts in surface natural waters, and its main storage in water systems is bottom sediments. The presence of a particular form of mercury in the aquatic environment is influenced by the acidity of the aquatic environment and its oxidative potential. In water, mercury migrates in two main phase states – in water solution (dissolved forms) and in suspension (suspended forms). In turn, in the water solution, it can be in the form of a divalent ion, mercury hydroxide, complex compounds (with chlorine, organic matter, etc.). Among the Hg (II) compounds, according to their environmental and toxicological significance, organomercury compounds play a special role. The most important accumulators of mercury, especially in conditions of pollution, are suspended matter and bottom sediments of water bodies. The highest concentrations of mercury are characterized by man-made silts that actively accumulate in rivers and reservoirs where industrial wastewater enters. The levels of mercury in them reach 100-300 mg / kg and more (with a background of up to 0.1 mg/kg). There are cases when the amount of mercury received from wastewater and accumulated in such silts amounted to tens and hundreds of tons. The normal functioning of such rivers and reservoirs, their practical use is possible only with the removal of contaminated sediments. The use of mercury-contaminated water for irrigation of agricultural land led to its accumulation in agricultural products to levels exceeding the MPC. The presence of mercury in the surface water bodies of Donetsk is largely due to the technogenic supply of this element. The chemical composition of river waters is directly dependent not only on the chemical composition of surface runoff and groundwater, but also on the chemical composition and quantity of discharged water. A significant contribution is made by the waste water of coal enterprises (mine water). The mercury content in mine waters is determined by their amount in the underground waters of coal-bearing deposits and the processes associated with the migration of this element from rocks to mine waters. Under certain conditions, mercury can accumulate in surface and ground waters in quantities that do not allow them to be used in the national economy, often negatively affecting water bodies for drinking and fishing purposes.

3. METHODS OF CHEMICAL ANALYSIS

3.1 Determination of dissolved gases in water

The amount of oxygen dissolved in the water is of great importance for assessing the state of the reservoir. Its content in water is affected by two groups of opposite processes: one increases the concentration of oxygen, the other reduces it. The first group of processes that enrich water with oxygen should include: the process of oxygen absorption from the atmosphere; release of oxygen by aquatic vegetation during photosynthesis; entering reservoirs with rain and snow water, which are usually supersaturated with oxygen. The absorption of oxygen from the atmosphere occurs on the surface of the water body, its rate increases with a decrease in temperature, with an increase in pressure and a decrease in mineralization. The photosynthetic release of oxygen by attached, floating plants and phytoplankton occurs the more strongly, the higher the water temperature, the intensity of sunlight and the more nutrients in the water. The dissolved oxygen content is subject to seasonal and diurnal fluctuations. Its decrease indicates a sharp change in biological processes in water bodies, as well as pollution of water bodies. The method is based on the ability of manganese nitrous hydrate to oxidize in an alkaline medium into compounds of higher valence, quantitatively binding oxygen dissolved in water, and then again pass in an acidic medium to divalent compounds, while oxidizing an equivalent (bound oxygen) amount of iodine. The iodine released in this case is determined by titration with thiosulfate.

3.2 Determination of iron in surface waters

Iron is constantly present in surface and underground waters; its concentration in these waters depends on the geological structure and hydrological conditions of the basin. The high iron content in surface waters indicates that they are polluted by mining or industrial wastewater, especially by the waters of metallurgical, metalworking, textile, paint and varnish industries, with agricultural effluents. Iron compounds do not have pronounced toxic properties, but they worsen the quality of water, giving it an unpleasant ferrous taste at a concentration of more than 0.3 mg/dm3. After washing in such water, rusty spots appear on the fabrics. The same stains appear on dishes, in the sink and in the baths. The permissible concentration of iron in drinking water is 0.3 mg / dm3. The total iron content in water is determined photocolorimetrically based on the reaction of Fe3+ ions with a rhodanide ion, sulfosalicylic acid, or o-phenanthroline. Colorimetric analysis of iron with sulfosalicylic acid is based on the reaction of sulfosalicylic acid with iron salts in an alkaline medium to form a yellow iron complex. This method can be set to 0.1-10 mg / dm3, iron with an accuracy of 0.1 mg/dm3. The reaction of o-phenanthroline with iron (III) ions in the pH range from 3 to 9 produces a red-violet complex compound. Direct determination is possible with an iron content of 0.05-2 mg in 1 dm3 of water, and no preliminary preservation of the sample is required.

3.3 Determination of the concentration of hydrogen ions (pH)

The potentiometric (electrometric) method for determining the pH value of water with a glass electrode is more versatile and accurate. Most serial pH meters allow measurements with an accuracy of 0.05—0.02 pH units. It is suitable for the analysis of waters with a wide range of mineralization and containing colored and suspended substances. The method is based on measuring the potential difference that occurs at the boundaries between the outer surface of the glass membrane of the electrode and the test solution, on the one hand, and between the inner surface of the membrane and the standard acid solution, on the other. Since the internal standard solution of the glass electrode has a constant activity of hydrogen ions, the potential on the inner surface of the membrane does not change and the measured potential difference is determined by the potential arising at the boundary of the outer surface of the electrode and the test solution. The measurements are made relative to the potential of another electrode, called the reference electrode. As the last one. choose such an electrode, the potential of which is practically independent of the activity of hydrogen ions, for example, calomel, silver chloride. The electromotive force that occurs in the measuring cells composed of an indicator (glass) electrode, reference electrodes (calomel, silver chloride) - the test solution and solutions with constant activity of hydrogen ions is a function of the activity of hydrogen ions (pH) in the test solution (and temperature). Content in surface waters. The value of the concentration of hydrogen ions (pH) in river waters usually ranges from 6.5-6.0, the ocean 7.9-8.3 pH. The pH of the water of mines and mines sometimes reaches one, and soda lakes and thermal springs ten. The concentration of hydrogen ions is subject to seasonal fluctuations. In winter, the pH value for most river waters is 6.8-7.4, in summer 7.4-8.2.

3.4 Determination of physical indicators of water quality

Physical indicators of water quality are its temperature, smell and taste, turbidity, transparency, color. Water temperature The temperature of the water depends on the location of the source, the time of year, and the temperature of the soils with which it comes into contact. The surface water temperature is subject to significant fluctuations, while the seasonal temperature fluctuations have little effect on the waters of underground sources. The most favorable temperature of drinking water is in the range of 7-12°C, it has the most pleasant and refreshing taste. Water with a high temperature contains little dissolved gases, so it does not quench thirst well and is unpleasant to the taste. The temperature is determined exclusively at the time of sampling by a mercury thermometer with a division price of 0.1-0.5°C, which is lowered to a given depth and kept for 3-10 minutes. Smell and taste The smell and taste of natural waters depend on the water temperature, water-soluble gases and the chemical composition of the impurities. The smell of water is determined by volatile odorous substances. Important role in the formation of the odor and taste of natural waters plays the vital activity of hydrobionts, especially the biochemical decomposition of organic matter by microorganisms, the selection of different specific organic compounds by some algae and microorganisms, particularly in mass their development, for example, at flowering of the reservoir, the nature of the chemical components flowing into the reservoir as a result of natural causes or wastewater enterprises. According to the nature of the smells are divided into two groups: odors of natural origin, caused by living and dead organisms in the water, surrounding soils, decaying plant remains, etc. The definition of such odors is given in accordance with the classification artificial odors caused by the impurities of some industrial wastewater, reagents for the treatment of tap water, etc. These odors are named after the corresponding substance: phenolic, gasoline, chlorine, etc. There are four types of water taste: salty, bitter, sweet and sour. Other types of taste sensations are called tastes. The reason for the taste of water may be the presence of hydrogen sulfide, petroleum products, in particular, phenol, and some salts. Thus, the salts of iron (II) and manganese (II) give the water a ferruginous taste, calcium sulfate –astringent, magnesium sulfate – bitter, sodium chloride – salty taste. The nature and intensity of the smell and taste of water are determined organoleptically: they give an expert qualitative characteristic and evaluate the intensity in points according to a five-point system. The colour of water Pure water in thin layers is colorless. In the thick layer, it has a bluish tint. Other shades indicate the presence of various dissolved and suspended impurities in the water. The color of natural waters of open reservoirs is most often due to the presence of humic substances that color the water in various shades of yellow and brown. The amount of these substances depends on the geological conditions, the nature of the soil, the presence of swamps and peatlands in the river basin, etc. Colloidal ferruginous compounds give the water shades from yellowish to green. When waste from various industries enters the water, its color may change depending on the color of the pollutants. Chromaticity is determined colorimetrically or photometrically by comparing the color of the water under study with a reference scale that simulates the color of natural waters. To do this, use the platinum-cobalt or dichromate-cobalt scale. The results are expressed in conventional units – degrees of color. The color of natural waters varies from a few units to several thousand degrees. Transparency and turbidity Transparency (or light transmission) water turbidity and turbidity are physical characteristics of water, depending on the presence of colored and suspended organic and mineral substances in the water. The measure of transparency is the height of the water column, at which you can observe a white plate of certain sizes lowered into the reservoir (Secchi disk) or distinguish a standard font of a certain size and type on white paper (as a rule, a medium-fat font with a height of 3.5 mm). With regular monitoring of the operation of water treatment plants and when determining the quality of water in the water supply network, the transparency of water is determined by the cross method. The results are expressed in centimeters with an indication of the measurement method. When the content of suspended substances in water is more than 3 mg / dm3, the inverse value of transparency is found – the turbidity of the water. The turbidity of the water is determined by comparing the turbidity of the test water with the standards, and is expressed in mg/dm3. Determining the transparency (turbidity) of water is a mandatory component of monitoring programs for the state of water bodies. The increase in water turbidity may be due to the presence of humic substances, colloidal iron compounds, suspended and colored substances that are waste products, as well as the mass development of algae, which is characteristic of polluted and atrophied reservoirs.

3.5 Definition of heavy metals

Heavy metals are distinguished from the general group of metals by their specific harmfulness to living organisms. The concept of "heavy metals" is not strictly defined. Different authors indicate different chemical elements in the heavy metal group. In environmental publications, this group includes about 40 elements with an atomic mass of more than 50 atomic units. N. F. Reimers refers to heavy metals with a density of more than 8 g / cm3, while distinguishing a subgroup of noble metals. Thus, copper, nickel, cadmium, cobalt, bismuth, mercury, and lead are classified as "heavy". The group of specialists working under the auspices of the United Nations Economic Commission for Europe and monitoring emissions of heavy metals into the environment also includes zinc, arsenic, selenium, and antimony.

3.6 Determination of chlorides and sulfates

The concentration of chlorides in reservoirs - sources of water supply is allowed up to 350 mg/l. In surface waters, the amount of chlorides depends on the nature of the rocks composing the basins, and varies significantly - from tenths to 1000 milligrams per liter. The concentration of chlorides in surface waters is subject to noticeable seasonal fluctuations that correlate with changes in the total salinity of the water. The principle of the method. The chlorides are determined by titrating a sample of the analyzed water with silver nitrate in the presence of potassium chromate as an indicator. Silver nitrate gives a white precipitate with chloride ions, and with potassium chromate - a brick - red precipitate of silver chromate. Of the precipitates formed, silver chloride has a lower solubility. Therefore, only after the chloride ions are bound, the formation of red silver chromate begins. The appearance of an orange-brown color indicates the end of the reaction. Titration can be carried out in a neutral or slightly alkaline medium. If the pH of the test sample is less than 7, the analyzed water is neutralized with 0.01 M sodium bicarbonate solution, and if more than 0.01 M sulfuric acid solution. pH control is carried out using a universal litmus test. The measurement of the mass concentration of sulfates by the titrimetric method is based on the formation of hardly soluble barium sulfate when adding a solution of barium chloride to the analyzed water. After almost complete precipitation of the sulfates, the excess barium ions react with the indicator to form a complex compound. In this case, the color of the solution changes from blue-violet (violet) to blue. To reduce the solubility of the barium sulfate precipitate, titration is carried out in an aqueous-alcohol or aqueous-acetone medium. The equations of the reactions write themselves. The measurement range is 30-300 mg

4. RESULTS OF HYDROCHEMICAL ANALYSIS OF WATER

Hydrochemical control of water quality consists of a system of control and observation: monitoring of the chemical composition of water in reservoirs and watercourses of the basin; incoming atmospheric precipitation; anthropogenic sources of pollution. The network of hydrochemical observations is created taking into account wastewater discharges, as well as types of water use. The composition and scope of hydrochemical observations are determined by the requirements imposed by the State administration and supervision bodies and the main water users. In this case, the following parameters are usually determined: mineralization; the oxygen content; Biological oxygen consumption (BOD); Chemical oxygen consumption (COD); content of basic ions, biogenic substances, petroleum products, detergents, phenols, pesticides, heavy metals. Physical parameters are also determined: color, temperature.

4.1 Result of hydrochemical analysis of surface waters

Рисунок 1

Conclusion

As a result of chemical analysis, we found that the indicator of sulfates exceeds the permissible concentration. They are an indicator of the pollution of surface water by industrial wastewater and groundwater by the waters of the overlying aquifers. Atmospheric sulfur dioxide (SO2), which is formed during the combustion of fuel and released in the roasting processes in metallurgy, can contribute to the content of sulfates in surface waters.

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