The Role Water Content in the Forming of the Ecological Condition of the Rivers of Siverskyi Donets Basin

Aims: The aim of the study is to determine the impact of the water content in the forming of the ecological condition of the rivers of Siverskyi Donets Basin (Ukraine) based on chemical and physico-chemical observations.

Study Design: The ecological condition of rivers is determined by their water contents and anthropogenic loading. Therefore, this study focused on the identification of the main trends in the changes of the quality of river water in the conditions of global warming impact.

Place and Duration of Study: The study addressed the industrial Chuhuiv, Zmiiv, Lysychansk cities located along the main river, the Udy River (discharges of municipal and industrial wastewater of the Kharkiv City), Kazennyi Torets, Kryvyi Torets, Bakhmutka (discharges of mine water from Donetsk coal basin) and Luhan (industrial and agricultural waste water) for 26 years from 1990 to 2015.

Methodology: Relationships between the indicators of water quality and the characteristics of water content were established from regression analysis. Determination of the ecological condition of the rivers was in the form estimated as a complex index of the ecological condition of their water, that based on the chemical and physico-chemical variations generated from many years of observations for them in the water.

Results: The study findings show that the indices of mineralization block and sanitary-toxicological block are increasing as the water content decreases, and the indices of toxicological and fishery blocks are increasing. The relationship between the indices of the ecological-sanitary block and water content was not found to be statistically significant. The overall index of the ecological condition of the rivers water steadily increases as the water content increases.

Conclusion: The water quality the rivers of the Siverskyi Donets Basin puts them into the categories of "polluted" and "very polluted" rivers. The analysis of the block indices of water quality generated in this study revealed that the substances of toxicological block (ammonium, nitrites, SSAS, heavy metals) and fishery block (petroleum products, phenols) are the most impacting on the water quality of the rivers of the Siverskyi Donets Catchment.