Impact Determination of Municipal Wastwaters on Neretva River Water Quality During Low Level Season by Using Water Quality Indices (WQI) Comparison

River ecosystems receiving wastewater discharges are exposed to pollution by various chemical, microbiological and physical substances. The aim of this study is to assess the water quality of the Neretva River, impacted by wastewaters from the municipality of Jablanica. Water samples collected over a three-year period (2017, 2018 and 2019) during the low-water season were analyzed at sites upstream and downstream from wastewater effluents. Values of a range of chemical and microbiological parameters were determined and the water quality index (WQI) was calculated based on these parameters. In addition to WQI, the biological water quality index (bWQI) was also determined in this study. Data analysis confirms a statistically significant chemical impact on the water quality of the Neretva River, while the bacteriological impact was not statistically significant.