Quantitative assessment of water quality in the Vidsichne reservoir (Zhytomyr, Ukraine)

Abstract

The modern approach to the implementation of water management activities is based on a quantitative assessment of the quality of water resources, which includes a certain set of indicators to reflect the needs of users in the composition and properties of water, to assess their condition, etc. Ecological assessment is a preliminary stage and a condition for ecological standardization of surface water quality. To analyze the compliance of water quality with ecological standards, the obtained results are compared with the values of ecological standards for the corresponding water body. The study carried out a quantitative assessment of water quality in the Vidsichne reservoir, near Zhytomyr (Ukraine). This assessment is based on the introduction of risk weighting factors from certain types of pollutants to the calculation formula of the integral indicator. Monitoring studies on hydrochemical indicators in the reservoir showed an increase in manganese content to 0.40 mg/dm3. To calculate the integral indicator of water quality, manganese and the related level of oxygen dissolved in water, biological oxygen consumption (BOC) were selected. It was established that the water in the reservoir belongs to the fourth quality class, that is, it is polluted. A model map of manganese concentration was built and the ecological coefficient of water quality was calculated, which indicates a 5-fold excess of ecological standards. The use of a graphic method of comprehensive assessment of the state of water in any reservoir is substantiated. The increase in manganese content is due to the seasonal increase in air temperature. The constructed mathematical model of the dependence of manganese content on temperature makes it possible to predict the state of the water body depending on climatic conditions and indicates an increase in the value of this indicator from 12°C and above. Quantitative assessment of water quality in the reservoir based on the sum of ecological indicators reflects the needs of users in the composition and properties of water and makes it possible to assess their condition.