TAILIEUCHUNG - Assessment of Water Pollution Levels in the Nyabugogo Catchment, Rwanda

Congestion charging schemes such as those introduced in Singapore and London, which have lead to a decrease of 40% and 30%, respectively, in traffic in the central business districts of both cities [27], have the potential to transform urban cities into more sustainable and liveable environments. In urban cities where people prefer using private modes of transport (cars) for commuting, as is the case in Auckland, work is needed to change people’s perception of public transport and thereby lead to changes in behaviour. This can be achieved by informing both the public and policymakers about the environment and health implications. | 40 The Open Environmental Engineering Journal 2011 4 40-53 Open Access Assessment of Water Pollution Levels in the Nyabugogo Catchment Rwanda I. Nhapi1 2 . Wali1 B. K. Uwonkunda1 H. Nsengimana3 N. Banadda4 and R. Kimwaga5 Faculty of Applied Sciences National University of Rwanda . Box 117 Butare Rwanda 2Department of Civil Engineering University of Zimbabwe Box MP167 Mt. Pleasant Harare Zimbabwe 3Faculty of Sciences National University of Rwanda . Box 117 Butare Rwanda 4College of Agricultural and Environmental Sciences Makerere University . Box 7062 Kampala Uganda 5College of Engineering University of Dar-es-Salaam . Box 35131 Dar-es-Salaam Tanzania Abstract This study aims to develop a comprehensive system of pollution monitoring and control in the Nyabugogo catchment of Rwanda which also includes the capital city Kigali through locating and highlighting pollution and its sources. Pollution hotspots were identified covering areas of both anthropogenic and natural pollution. The study focused on water quality assessment especially the identification of the critical points of pollution hotspots by measuring selected physico-chemical parameters in the Nyabugogo River system. An extensive monthly water quality monitoring study was conducted from October 2008 to May 2009 and covered nutrients organic and heavy metal pollutants. The parameters covered are Ammonium-Nitrogen NH4 -N Nitric-Nitrogen NO2 N Nitrate-Nitrogen NO3 N Sulphates SO4 Phosphates PO4-P Chemical Oxygen Demand COD Biological Oxygen Demand BOD5 Dissolved Oxygen DO Total Dissolved Solids TDS Chromium Cr Iron Fe Lead Pb Manganese Mn Zinc Zn Conductivity EC pH and Turbidity. The samples were collected preserved and analyzed in the laboratory using standard methods whilst TDS conductivity turbidity and pH were measured in the field using HACH field kits. The water quality study revealed that both urbanized and rural sub-catchments have serious but different types of pollution. For example the

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