Assessment of Water Pollution Levels in the Nyabugogo Catchment, Rwanda

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 , 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 water from rural areas is heavily contaminated with nutrients, suspended sediments (due to a lot of erosion upstream) and organic materials whilst from urban areas the predominant pollutants are heavy metals and some nutrients. It was therefore concluded that the Nyabugogo River system is very heavily polluted and urgent action to control both rural and urban pollution is required. Further studies are required to isolate and quantify the sources of this pollution.

Physicochemical Quality of Water and Health Risks Associated with the Consumption of the Extant African Lung Fish (<i>Protopterus annectens</i>) from Nyabarongo and Nyabugogo Rivers, Rwanda

“…It is later fed by other rivers from the urbanized parts of Kigali such as Rwanzekuma, Ruganwa, Mpazi and Yanze. Floriculture, sugar processing at Kabuye works sugar industry, sugar cane plantations, agrarian and mining activities along this river are the major sources of anthropogenic pollution [8].…”

“…The pH values recorded in this study agreed well with those recorded by previous reports. Nhapi et al [8] reported a pH of 7.24 ± 0.18 at Rwesero, the first point after Nyabugogo river flows out of Lake Muhazi. Further, a more or less constant pH in Nyabugogo swamp was reported [11] and the author implicated this to be the effect of high pH of water in Rwanzekuma and Ruganwa rivers which receive alkaline reagents from Usine Textile Du Rwanda (UTEXRWA) textile industry and other factories in Kigali city.…”

“…Several industries have sprung up and are causing pollution of water bodies due to discharge of untreated industrial wastes as well as sewages into surrounding rivers [8]. Thus, conservation and efficient utilization of water to meet the ever-growing requirement by the population and industries is necessary and this can only be achieved through constant monitoring of these water resources [9].…”

“…Environmental studies have reported pollution of major Rwandese rivers such as Mpazi, Nyabarongo, Rusine and Nyabugogo [8,[10][11][12][13]. Nyabugogo river, a tributary of Nyabarongo river (a tributary of Akagera transboundary river) pour its water into Lake Victoria, the life artery of East African countries [14].…”

Review on Water Resources Management and Key Threats in Rwanda, East Africa

“…This however, affects the municipal wastes management due to informal settlements, expansion of the city and industrialization whose final results is water quality degradation and pollution as well (Mohammed et al, 2017;Uwimbabazi, Lawrence, 2011). Despite the present Governmental initiative (which is not yet fully completed) of re-allocating industries from or near watersheds to appropriate and well equipped location (Rwanda Special Economic Zone), their former location led to immense wetland and biodiversity degradation (Etale, Drake, 2013;Nhapi et al, 2011). In addition, the report of the Kigali City Conceptual Master Plan (Kigali…, 2007) indicates that the city will keep expanding in size and its inhabitants will almost triple in the next 25 years.…”