The Assessment of Heavy Metals Pollution in the Nyabarongo River Sediments – Case Study: Mageragere Sector

Abstract

The accumulation of heavy metals in rivers’ sediments near industrial wastes and mining activities has been a serious issue in developing countries including Rwanda and it has caused different environmental impacts on aquatic and terrestrial lives. Environmental studies have reported heavy metals pollution (lead, manganese, copper, zinc, nickel, iron, and cadmium) in major Rwandese rivers such as Mpazi, Rusine, and Nyabugogo.  The increase in heavy metal concentrations in the environment results in abnormal enrichment, which in turn, affects the surrounding environment. This study aimed to investigate the heavy metals in Nyabarongo sediments, Mageragere sector using both X-ray fluorescence (XRF) and Atomic Absorption Spectrometer (AAS) instruments. Sediments samples were collected systematically on four sampling stations and the results showed that the Cadmium (Cd), Lead (Pb), and Manganese (Mn) concentrations among the investigated heavy metals are above the Rwanda Standard Board (RSB) and World Health Organization (WHO) guidelines for soils and sediments, meaning that those metals are the measure pollutants in the sediments of Nyabarongo River and the study has recommended the people around the river to reinforce the erosion control measures and not to use Nyabarongo water for domestic use and animal farming activities because of the concentration of heavy metals it contains that are toxic to animals, plants and micro-organisms.

Keywords: Heavy metals; Nyabarongo River; Pollution; River sediments; World Health Organization (WHO).