DOI: 10.36347/sajb.2023.v11i12.001

Pages: 414-427

Rivers often play a vital role in the transport of major natural chemicals entering through a variety of pathways, including atmospheric inputs, chemical weathering of minerals, mechanical erosion of rocks and soil particles, and soil leaching. Increased anthropogenic activities on the shoreline of Lake Kivu combined with existing land use practices may increase changes in river water quality and composition. Knowing the physico-chemical and biological contribution of each tributary of the lake is vital for the management of its biodiversity. This study aimed at determining the physico-chemical characteristics, water quality indices and identifying the polluted tributary rivers that feed Lake Kivu on the Congo side. The physicochemical characteristics were determined for each water sample following water quantity protocol for each analysis at the Malacology Laboratory of the Biology Department of Lwiro Research Center. Two pollution level indices were used to determine the level of organic pollution in watercourses. The physico-chemical characteristics of rivers vary from one river to another depending on the anthropogenic activities around the different sub-basins of these rivers. The state of the rivers presented here reveals that the majority of them are moderately polluted and others slightly polluted. No rivers were very heavily polluted or good in the Lake Kivu basin on the DR Congo side. There is a strong or moderate correlation between certain parameters and the water quality indices used in this study (LISEC and OPI). Due to increase in anthropogenic activities near watercourses, further research is needed and the combination of several complex analytical methods should be used in the future to better characterize these waters.