Tolochyk I. Еcological state of the Styr river in conditions of anthropogenic loading within Rivnenska oblast

The dynamics of ecological assessment of water quality for 2011-2016 was investigated. The optimal and permissible water quality loss in the Styr river in Volyn Highland and Volyn Polissya region was determined. For the first time, the classification of water quality loss was proposed for the studied region. The calculations of the magnitude of the anthropogenic load and the estimation of the overall ecological status of the river basin have been made, anthropogenic component of water quality has been calculated. The hydrophilic flora, plankton groups and production-destructive processes of the Styr river was determined. 125 species, 75 genera and 38 families of hydrophilic flora were identified in the surveyed plots of the Styr River, of which 8 were adventitious and 6 were rare species. For the first time in Rivnenska oblast Batrachium rionii was found, which belongs to the Red List of aquatic macrophytes of Ukraine and is a highly perceptible species. In all of the studied sites plankton species were always present with the species of the Bacillariophyta division. The primary gross, net production of organic matter was calculated, destructive processes were studied, production and destructive coefficients were calculated. At the present stage of the functioning of the Styr river ecosystem its trophic state is ensured by the predominance of primary gross output over the destruction of organic matter. According to the results of the research, a program to improve the environmental situation in the Styr river within Rivnenska oblast has been proposed.