THE WATER POLLUTION DEGREE INTEGRATED ASSESSMENT OF THE LOWER SECTION OF THE DNIESTER RIVER

Abstract

Surface fresh water resources ensure the viability of human society and biota, they are limited and vulnerable. Intensive use of river water resources for the needs of society leads to changes in the hydroecological state of water bodies, so monitoring the degree of pollution of the aquatic environment remains relevant. Modern water use in the Dniester River basin demonstrates a different combination of changes in water intake and discharges of polluted water over time. The problem of deterioration of river water quality after the Dniester River leaves the territory of the Republic of Moldova is especially acute. The purpose of the paper was to conduct the water pollution degree integrated assessment of the Lower Section of the Dniester River for the period 2011–2020. The article presents the temporal dynamics of changes in the degree of pollution of the aquatic environment in the Dniester River – village Mayaky (16 km from the river mouth) by hydrochemical parameters. During 2011–2020, there was a steady decrease in the average annual concentrations of Chlorides, Sulphates and Suspended solids. In 2020, there is an excess of monthly concentrations of total nitrogen and an increase above the maximum permissible concentrations of Nitrites. The water pollution degree integrated assessment of the Lower Section of the Dniester River for 2011–2020 in accordance with the quality standards of surface water bodies intended for fishery needs, according to the coefficient of water pollution, which takes into account the effect of summation of pollutants. Emphasis is placed on the directly proportional dependence of the coefficient of water pollution on the amount of return polluted water discharged into surface water bodies (2017–2019). The necessity of carrying out environmental protection measures by economic entities aimed at reducing the inflow of surface return waters into the surface waters of the Dniester River, containing substances that have the effect of summation, has been proved.