Statistical analysis of water quality parameters in the basin of the Nišava River (Serbia) in the period 2009–2018

This paper analyzes water quality from four hydrological stations in the Nišava river basin 2009–2018 based on following parameters: pH, conductivity, O 2 saturation, BOD 5 , suspended solids, total oxidized nitrogen, phosphates, turbidity and coliform bacteria. Authors have applied WQI (water index) as most reliable indicator of watercourses pollution for setting surface flow quality. Statistical analysis variance (ANOVA) using t-test inferential statistical post-hoc Tukey test were to evaluate statistically significant differences between specific data groups. The results show that bad was registered all profiles an annual basis (WQI = 65–71). pH decreases downstream, while values turbidity, TON, phosphates bacteria gradually increase. waters at station Niš belong third class they are mostly loaded with organic matter originating waste sewage industrial both urban rural areas.