The thesis investigates the ecological state of the upper reaches tributaries of the Prypyat River and the adaptation of European approaches to phytoindication in the system of surface water quality monitoring. Scientific analysis of objectivity and official recognition of indicative criteria for assessing the state of aquatic ecosystems has been conducted. The belonging of the upper reaches tributaries of the Prypyat River has been established according to the descriptors of the EU Water Framework Directive and the general natural conditions of the rivers’ basins (Turia, Vyzhivka, and Tsyr) have been characterized.
According to the studies of the surface water quality changes in terms of hydrochemical parameters in spatial and temporal dynamics in representative observation sites mainly II–III quality classes have been revealed – the state of “good-satisfactory”, the degree of purity “clean-polluted”. It was noticed that the substances of the tropho-saprobiological block have a strong impact on the water quality formation, and the temporal dynamics of hydrochemical parameters indicate the spring self-cleaning ability and deterioration of environmental conditions in the summer and autumn period.
The analysis of the aquatic and coastal-vascular plants of the rivers Turia, Vyzhivka, and Tsyr revealed 69 species belonging to 44 genera, 25 families, 4 classes, 3 divisions, which are representatives of five ecotypes: hydrophytes, gelophytes, hygrohelophytes, hygrophytes, and hygromeso- and mesophytes. According to the results of the phytoindication assessment, based on the European MMOR method, there is a change in the ecological state of surface waters in the test sites of the studied rivers from class II (MIR = 35,4-42,7 31.2-34.8) – good quality, mesotrophic state to class III (MIR = 31.2-34.8) – satisfactory quality, eutrophic state.
Mathematical relations between the obtained results of the ecological status assessment of the surface waters of the above-mentioned rivers indicate a significant effect size between them (η2 = 0.973-0.997), with relatively higher values comparing the worst values results. Equations, based on the multifactorial dependence results, are offered. It allows using the Macrophyte Index as a prognostic criterion in the monitoring system of the seasonal dynamics of the surface water quality of the upper reaches tributaries of the Prypyat River.
