STATE AND QUALITY OF WATER IN THE DESNA RIVER BASIN (WITHIN THE CHERNIGIV REGION)

The Desna River is a tributary of the Dnieper with a total length of 575 km within Ukraine. 468 km of them flows through the Chernihiv region. The main pollution sources of the water bodies in the Chernihiv region are utilities. Continuous monitoring of the surface water state is relevant and necessary, as it allows to give a reliable water quality assessment, to identify the anthropogenic impact factors and to assess the technogenic loading in order to establish the level of water use and to develop a set of measures to improve the state of water and the environment in general. The materials of monitoring observations of the water quality indicators of the Desna river for a long-term period, as well as the materials of the Ecological passports of the Chernihiv region concerning the water use indicators, were used as the initial data in the work. The analysis of the hydrochemical regime of the Desna River over a long period was performed using a graphical method. The assessment of the technogenic impact on the water bodies of the region was performed using the method of assessing the efficiency of water use based on the water consumption and sewerage efficiency coefficients. The analysis of the content of the water quality indicators showed that constant exceedance of the MPC (Maximum Permissible Concentrations) in the waters of the Desna River within the Chernihiv region was observed in the content of phosphates and nitrites, as well as total iron and manganese. The results of the assessment of the technogenic impact on the water basin of the Desna River showed that the drainage coefficient underwent certain changes with the best indicators in 2015–2016. No sharp fluctuations in the values of the water supply coefficient were observed. The best values of the water use efficiency complex coefficient were noted in 2015–2016. In general, in recent years the efficiency of water using indicators of the Desna River water in the Chernihiv region has corresponded to the average indicators. The results of the assessment of the technogenic impact on all components of the environment in the Chernihiv region showed that in recent years there has been a tendency to reduce the technogenic impact complex indicator. In general, the Chernihiv region can be attributed to the second ecological district with a moderate technogenic loading level.