Tendency of Change in Water Quality of the Main Shirvan Collector Over a Long Period

The article examines the tendency of changes in the hydrochemical regime of the water of the Main Shirvan collector over a long period of time and the suitability of the collector water for irrigation. Continuous laboratory analyzes performed between 2004 and 2019 were compared to 1986. According to experimental data, it was determined that the hydrochemical regime of the collector water is gradually improving, and the salt content is decreasing. The degree of mineralization of the collector water decreased by 2.3 times, the total hardness by 2.2 times, the number of chloride ions by 10.5 times, the number of calcium ions by 1.3 times, the number of magnesium ions by 2.8 times, the total number of cations sodium and potassium decreased by 3.9 times. For 2004–2019 biochemical oxygen consumption in collector water increased 7.9 times, chemical oxygen demand increased 7.5 times, and the number of suspended particles increased 9 times. The amount of iron ions in water decreased by 2 times, while the amount of aluminum and zinc did not change. The suitability of collector water for irrigation was determined according to 7 internationally accepted assessment criteria. Collector water is considered suitable for irrigation in accordance with 6 assessment criteria — the degree of salinity, irrigation coefficient, sodium sorption coefficient, potential salinity, water alkalinity index and percentage of sodium, as well as 1 criterion not suitable for irrigation — the percentage of magnesium. Collector water can be used to irrigate crops.

ON MONITORING THE HYDROLOGICAL AND HYDROCHEMICAL REGIME OF THE BLACK SEA WATERS

The article briefly describes the main facts and milestones in the development of methods for monitoring the hydrological and hydrochemical state of the Black Sea waters from the 19th century to the present day. It is shown that the modern understanding of the hydrological and hydrochemical processes of this unique sea basin resulted from the intensive work of many oceanographers over the past centuries. Par-ticular attention is paid to the oxygen regime of the Black Sea.

Long-term changes in the chemical composition of the water of the Inhulets and Saksahan rivers within the Kryvorizkyi Iron Ore Basin (1980–2020)

The article presents the generalized results of chemical composition research of waters from Inhulets and Saksahan rivers on the territory adjacent to the Northern and Inhulets with pumping of underground waters (mine and quarry), which have an abnormal chemical composition, high mineralization and contain high concentrations of microcomponents. The following scheme of mine water utilization is used in the Kryvyi Rih iron ore basin: the mines of the northern part of Kryvbas discharge water into the tailings dam of Northern Iron Ore Dressing works (Northern GZK); mines of the southern part discharge mine waters into the storage pond of the Svistunov creek during the year, and in the winter its waters are discharged into the Inhulets River with subsequent washing of the river in the spring-summer period. Such treatment of mine and quarry waters has led to the formation of a hydrochemical anomaly on the territory of Northern GZK with the center in the tailings. The mineralization of water in the pond reaches 23 g / l (2020). There is a high content of microcomponents: lead, cadmium, vanadium, manganese, boron, bromine, nickel, mercury, thiocyanates. As a result, the mineralization of the Saksahan River water increases over time (up to 5.4 g / l), the content of microcomponents also increases and becomes quite high. Prolonged use of the Inhulets River for utilization of mine water from the Svistunov creek storage pond has led to a change in the type of water: instead of type II (river water), Inhulets water belongs to the type III (metamorphosed waters). There are no regularities in the change of chemical composition of water (hydrochemical regime) in Inhulets, which is a consequence of the introduction of the scheme "discharge – flushing" for the disposal of mine water. Among the microcomponents in the water of Inhulets there is an increased content of vanadium, boron and bromine (7–8 times), single excess of lead content. The analysis of equilibria in the carbonate-calcium system of the Inhulets and Saksahan rivers confirmed that the existing hydrochemical regime for the studied rivers is stationary, thus, the environmental measures implemented will not have rapid consequences.

PRACTISE OF ORGANIZING LAKE COMMERCIAL FISH FARMS IN CONDITIONS OF LAKE OZGENT

The article presents the results of the researches conducted on Lake Ozgent (the Kyzylorda region). The data on hydrochemical regime of the lake, ionic composition, composition of biogenous compounds, oxygen and thermal regimes were collected and analysed. There has been done the assessment of food supply and current state of the ichthyofauna. According to the obtained data, the recommendations about using Lake Ozgent were made, the recommended meliorative events (meliorative fishing, repair of hydroconstructions) were held and stocking the fishing material of carp was carried out. Based on the work results it has been established that in the conditions of Lake Ozgent the pure gain in 5 months of cultivation (on extensive technology when using only the natural food supply) made 385.6 g in a carp, 301.4 g in a white silver carp and 428.7 g in a grass carp. In the full catch of commodity fish species, the overall fish productivity of Lake Ozgent will make 101.9 kg/hectare, of them carp will take 43.4 kg/hectare, grass carp - 13.5 kg/hectare and white silver carp - 45 kg/hectare. The growth of the grown-up fish in Lake Ozgent corresponds to biotechnical standards of fish cultivation in the in polyculture of the feeding lakes.

MODERN HYDROMORPHOLOGICAL, HYDROBIOLOGICAL CHARACTERISTICS AND STATE OF FISH POPULATIONS OF LAKE GALICHSKOYE AND LAKE CHUKHLOMSKOYE IN KOSTROMA REGION

Hydrochemical, hydrobiological and ichthyological studies of the two largest lakes in the Kostroma region - Galichskoye and Chukhlomskoye for the period 2005–19 were carried out. Current state of the fish population in comparison with previous periods was analysed. Area of water bodies was updated according to geographic information systems data for 2017–19. The collection and processing of hydrochemical and hydrobiological samples were carried out according to standard methods. The collection of ichthyological materials was carried out by conventional methods using fry drag, small-mesh seines and fixed nets. The boundaries of the lakes were digitized using Landsat satellite images. The hydrochemical indicators of both lakes are within the limits of fishery standards. The hydrochemical regime of Lake Galichskoye is stable. The rise in the water level of Lake Chukhlomskoye had a positive effect on its hydrochemical regime. It has been established that both investigated lakes are currently, as before, highly productive water bodies. According to the concentration of chlorophyll “a” they have a β-eutrophic status, according to quantitative indicators of phytoplankton development they correspond to a high eutrophic level. According to the quantitative indicators of zooplankton, Lake Galichskoye is a low-forage water body (0.37 g/m3), and Chukhlomskoye is a medium-forage water body (2.12 g/m3). Lake Galichskoye is medium-fodder, and Lake Chukhlomskoye is high-forage lakes for benthofagous fish. According to indicator species of zoobenthos, the water of both lakes is classified as an α-mesosaprobic zone, polluted (quality class IV). The species richness of fish on Lake Galich – 16 species, on Lake Chukhloma – 12 species, ichthyomass – 221.9 and 176.5 kg/ha, respectively. It was noted that in the reservoirs over the past two decades, serious changes have occurred in the structure of the fish population. In both lakes, perch fish were replaced by cyprinids, which is associated with the process of eutrophication. In Galichskoye Lake, after a sharp decrease in fishing load since 2005, there has been a significant increase in the number of small-sized fish species caused a corresponding increase in stocks of predatory species (pike and pike perch). In the Lake Chukhlomskoye, the ecological niche of the crucian was occupied by the bream, which was acclimatized in the reservoir almost a century ago. It was determined that during the growing season the average area of Lake Galichskoye is 7124.3 ± 57.5 hectares, of Lake Chukhlomskoye – 4862.7 ± 14.7 hectares.

LINEAR AND WEIGHT GROWTH OF THE WALLEYE IN THE TEREK-CASPIAN FISHERY SUBDISTRICT

The article presents the linear and weight growth of the pikeperch in the coastal and inland waters of the Terek-Caspian fishery subdistrict. The dynamics of the linear and weight growth of the pikeperch on the Daghestan coast of the Caspian Sea and in the inland waters of Daghestan in the long-term aspect is shown. It was revealed that the average length and weight of the same-age pikeperch in different years are at a close level, which indicates stable conditions of living, feeding and food supply in the study period. The formation of the pikeperch populations in the Terek-Caspian region is influenced by the dynamic environmental conditions (sea level, hydrological and hydrochemical regime, water pollution). At the same time, the influence of habitat conditions is not critical and does not lead to significant changes in the qualitative and quantitative characteristics of the pikeperch and its forage objects in modern conditions.

FEATURES OF THE WINTER HYDROCHEMICAL REGIME OF THE IVANKOVO RESERVOIR IN THE LONG-TERM ASPECT

Проведен анализ современного состояния и изменения за многолетний период характеристик зимнего гидрохимического режима Иваньковского водохранилища. Представлены осредненные за период с 2013 по 2019 гг. концентрации главных ионов и биогенных элементов, значений минерализации воды, физико-химических и показателей органического вещества, а также концентраций марганца в различные сезоны года. Показаны отличия характеристик гидрохимического режима водохранилища зимой в сравнении с другими сезонами. Установлена изменчивость значений зимой по плесам водоема и за многолетний период. The analysis of the current state and changes in the characteristics of the winter hydrochemical regime of the Ivankovo reservoir over a long period of time is carried out. The average values for the period from 2013 to 2019 of the concentrations of major ions, biogenic elements, water mineralization values, physico-chemical and organic matter indicators, as well as manganese concentrations in different seasons of the year are presented. The differences in the characteristics of the hydrochemical regime of the reservoir in winter in comparison with other seasons are shown. The variability of the values in winter along the reservoir reaches and over a long-term period is established.

The Lake Pizanets (Republic of Karelia, Russia) – a new site for establishingthe protected area

A survey of the morphological and hydrological characteristics of the lake and analysis of the species composition, abundance, and biomass of phytoplankton, phytoperiphyton, zooplankton, and zoobenthos were carried out as a part of the complex study for establishing a new protected area “Lake Pizanets”. The effect of natural and anthropogenic factors on the hydrochemical regime and structure of aquatic ecosystems of the lake was assessed. The trophic status of the lake, its saprobity, and the significance of particular communities and bioindication indices were estimated. The species composition and dominant species of the studied communities of the lake were quite typical for freshwater bodies of the region. Despite the fact that the abundance and biomass of macrozoobenthos turned out to be lower than in other lakes of Eastern Fennoscandia, generally, the abundance and biomass of phytoplankton, phytoperiphyton, zooplankton, and zoobenthos evidenced on relatively high degree of their development in the lake Pizanets, as well as on their activity and stability. At the same time, the species, forming the communities, differed in size noticeably; therefore, significant discrepancies were found between the lists of taxa dominating by abundance and by biomass. The biotic indices and hydrochemical indicators indicated mainly a low degree of pollution, so the lake waters could be classified as belonging to water purity class II. Nowadays, the lake is not affected by significant anthropogenic load. However, according to the program of establishing new protected areas, further control of the hydrobiological and hydrochemical indicators of the reservoir, as well as its inclusion in the environmental monitoring program is undoubtful.

ASSESSMENT OF THE QUALITY OF THE LAKE KOPA OF THE CITY OF KOKSHETAU BY HYDROCHEMICAL INDICATORS

This article provides a brief description of the Kopa Lake in the Akmola region. The results of the study of the ecological state of the water body for 2018...2020 are presented. The analysis of the hydrochemical regime of water is carried out, the index of water pollution is determined. According to the data we received, the reservoir is exceeding the MPC in some indicators.

Features of the long-term dynamics of development hydro/chemical parameters of the water of the Shershnevsk Reservoir

The article presents an analysis of the long-term dynamics of the hydrochemical conditions of the water of the Shershnevsky reservoir for 1972-2020 during the spring flood and summer low water. The features of the development of water quality indicators over time are determined: pH, mineralization, turbidity, color, suspended solids, the content of dissolved oxygen and organic substances by permanganate oxidability and BPK5, as well as changes in the concentrations of ammonium, nitrite, nitrate nitrogen and phosphates. In the water of the Shershnevsky reservoir for the period 1972-2020, trends of a significant decrease in mineralization, turbidity and permanganate oxidability were noted in both phases of the hydrological mode. In the summer low water period, a significant increase in chromaticity, oxygen content in water and orthophosphates was detected.. The revealed features of changes in the hydrochemical regime indicate an increase in the processes of anthropogenic eutrophication of the Shershnevsky reservoir – the only drinking source of the Chelyabinsk agglomeration and make it possible to predict the state of the aquatic ecosystem. The information obtained can be implemented in the process of making management decisions on environmental protection measures for the Shershnevsky reservoir.