Assessment of ecological state of watercourses of the Rybinsk water reservoir

The Rybinsk water reservoir refers to the major sources of drinking water supply, so the assessment of the ecological state of watercourses is very urgent. This work contains the assessment of the ecological status of the Rybinsk water reservoir (the rivers Yagorba, Koshta, Mologa) based on the data of physico-chemical analysis and biotesting results. The biotesting was carried out with Paramecium Caudatum in automatic mode of the soft-hardware complex “BioLAT”. The growth of infusorium was determined in 72 hours of their stay in the sample, the degrees of toxicity were determined due to results. The analysis of chemistry dynamics from 2006 till 2014 showed a modest improvement of the water state of the river Koshta and deterioration of the water states of the rivers Yagorba and Mologa. The priority water pollutants of investigated rivers are organic substances, iron, zinc and copper. The compounds of these substances are caused by natural factors. High levels of sulphate ions, nitrite and ammonium nitrogen were found in the river Koshta. The waters of investigated watercourses showed tolerance and moderate toxicity levels. The study found that the watercourses of the Rybinsk water reservoir subjected to human impacts are amplified. The main sources of pollution of watercourses are housing and agriculture, metallurgical and chemical production.