Integrated Assessment of the Southern Bug River Basin Water Quality and Calculation of their Self-Cleaning Capacity

Purpose. To carry out the surface water quality assessment of Southern Bug river basin and to investigate ability self-purify. Methods. Statistical calculations, system analysis. Results. The long-term dynamic integrated index values during 2000-2016 was heterogeneous, but general trend indicated a slight increase due sanitary-ecological pollution index. highest level observed in Khmelnytsky city Alexandrovka settlement. assess self-purification capacity waters, hydrological zoning taken. According it three regions were identified by types intra-annual runoff distribution: Verkhnyobuzky, Serednyobuzky Nizhnobuzsky. obtained results EC coefficient calculations for mineral nitrogen compounds show inability rivers self-purify Verkhnyobuzky regions. Instead, is preserved phosphorus compounds.Using nonparametric Mann - Kendall test allowed estimate long term nutrients Nizhnobuzsky region. Trends N-NO3-, N NH4+and Р-РО43- are characterized positive statistical parameter, which means increasing these elements’ concentrations. Conclusions. Rivers classified as "good, clean enough". main ecological hydrochemical problems indicators toxic action. criterion indicate their (in upper middle parts basin) self-purification. Using Mann-Kendall determining changes nutrient shows an upward trend, that