Water Quality Estimation in the Kotorosl' River Basin Based on Zoobenthos Composition

Water quality and the levels of pollution in biological communities of the Kotorosl' River and its major tributaries (the Sara, Lakhost', Mogza, and Pakhma rivers) are estimated by using a considerable body of hydrobiological characteristics (the Pantle–Buck saprobity index and its modifications by Rotshain and the indices of species diversity developed by Shannon; Balushkina; Woodiwiss; Parele; Toderash; Goodnight and Whitley; and Carr, Hiltunenn, and Wright) from the data on the seasonal dynamics of macrozoobenthos. An ecological and sanitary classification of water quality that was developed for this type of rivers is presented. Indices based on the characteristics of oligochaetes, as well as on the taxonomic composition of communities and characteristics of the most indicative species, are shown to be the best choice for characterization of organic pollution prevailing in the Kotorosl' River basin.