Hydrology, WQI, Water pollution, Physicochemical parameters, Watershed management, Riparian zones
Abstract :
[en] The Lake Kivu ecosystems are of great contributions to the economy and livelihoods of the riparian communities in Rwanda and the Democratic Republic of Congo. However, the lake’s biodiversity and its riparian zones are increasingly threatened by anthropogenic activities. This study aimed at assessing the water quality of the major tributaries in the eastern catchment of the lake. The samples were collected from seventeen rivers during rainy and dry seasons annually from 2018 to 2021. A total of 15 physicochemical parameters were tested, including pH, electrical conductivity, turbidity, Total Dissolved Solids (TDS), nitrates, nitrites, ammonia, phosphate, chloride, copper, manganese, total iron, zinc, and total hardness. The analysed parameters were used to determine the water quality index (WQI). A correlation between different parameters were calculated to determine the co-occurrence among pollutants and understand their causes and related effects. The results indicated that the primary contributors to high pollution levels were turbidity, ammonia, and nitrate content in most rivers, with moderate contributions from nitrites and phosphates. River Sebeya had the highest turbidity level with an average of 1 267.75 NTU (Neplelometric Turbidity Unit), while the concentration of nitrate averaged 22.38 mg l-1. Significant correlation between turbidity and Total Suspended Solids (TSS) on one hand and phosphates and ammonia on the other hand were recognized. Nickel showed the highest concentrations among the heavy metals analysed in different rivers with an average concentration of 4.5 mg l-1. From the obtained results, the WQI was deduced and an average of 284.37 indicated a very poor water quality in all analysed rivers. The poor water quality can be attributed to increased human activities including intensive agriculture, mining, industrial water uses, and effluent discharge into the lake’s tributaries. Existing policies on environmental protection for the riparian zones of the lake should be reinforced.
Disciplines :
Physical, chemical, mathematical & earth Sciences: Multidisciplinary, general & others
GLOW10 is part of an ongoing series of symposia organized by the GLOW (Great Lakes of the World) Chapter of the Aquatic Ecosystem Health & Management Society (AEHMS). It is the silver jubilee event celebrating 25 years of GLOW. The first GLOW symposium was organized more than 1996 in Victoria Falls, Zimbabwe. Since then the AEHMS has launched a continuing series of GLOW symposia regularly in order to promote interaction and communication amongst various Great Lakes/Large Lakes researchers across the world. The purpose of GLOW is to establish a global platform where ecosystem-based studies of the structure, function and performance of Great Lake ecosystems are promoted, organized and synthesized. In addition, GLOW propagates ecosystem science-based management from an integrated, multi-trophic and multi-disciplinary perspective.
GLOW10 is the eighth of the series organized in the African continent. The AEHMS always co-organizes GLOW conferences with local hosts with regional knowledge to improve participation of African scientists. The AEHMS is proud to be partnering with the Lake Victoria Fisheries Organization (LVFO), the African Center for Aquatic Research and Education (ACARE) and the Tanzania Fisheries Research Institute (TAFIRI), to promote the health of the African Great Lakes. The AEHMS is delighted to collaborate with its partners in an international exchange of ideas and peer reviewed high quality publications.
We are indeed pleased to report that GLOW10 had overwhelming response. Selected presentations will form the basis of an interesting GLOW program in Dar es Salaam. Later it is planned to publish selected papers in special issues of the journal, Aquatic Ecosystem Health and Management (AEHM) published jointly with Michigan Statue University Press, USA and/or a book under the Ecovision World Monograph Series published by AEHMS and Michigan State University Press.
We greatly appreciate the assistance of Organizing, Scientific and Local Arrangements Committees towards the facilitation of this meeting. Sincere thanks to the AEHMS secretariat (Jennifer Lorimer, Lisa Elder) for their assistance in all aspects of the organization of GLOW10.
We are optimistic that the GLOW10 symposium in the beautiful surroundings of Dar es Salaam, will be a productive, scientific and interesting experience generating new ideas, energy and momentum for the continued success of the AEHMS-GLOW Chapter and its future activities.
