A new research has established that at 47.8 per cent household waste is the leading cause of pollution in Nyabarongo River.

Household waste mainly comprised of rubbish, garbage and sewage enter Nyabarongo River through the ravine Nyabugogo swamp that connects to it.

With a length of 351 km, Nyabarongo is Rwanda’s major and longest river.

The research carried out from April to October 2021 and commissioned by Democratic Green Party also found out that the absence of soil erosion control accounts for 24.4 per cent of the factors that pollute the river.

At a rate of 10 per cent, industrial waste is ranked 3rd in polluting Nyabugogo swamp

The industrial effluents and by-products are discharged in the water bodies by a number of industries in the Kigali City wetland system including a textile industry, the iron industry which manufactures iron sheets, paint factories and the Kabuye sugar factory among others, the report says.

High levels of zinc, researchers say, were detected in the river—which can potentially cause a wide range of medical problems to the human body including birth defects, loss of smell and organ damage.

The quality of Nyabarongo River was also found to be deteriorating due to washing of minerals, mining activities in rivers that feed it, dumping mineral waste left-over soil and discharging wastewater into the river.

Apart from the poisonous chemicals, the report shows, mining companies are also aiding the massive loss of topsoil which is channelled into Nyabarongo River, which is partly why the river has a distinct brown colour.

Car garages waste and waste from livestock are among the sources of pollution in the water body

Effects of pollution on Nyabarongo River

According to the study, many respondents during the research confirmed that diseases arise due to polluted water from the Nyabarongo River. 

Researchers also said that the pollution may cause diseases such as cancer due to heavy metals that are found in the river. In addition, the microbes in the river cause water-borne diseases like diarrhoea and cholera.

However, they said that there is no assessment yet done in the clinics or hospitals showing the extent to which people are being affected or sick because of using contaminated polluted water of Nyabarongo River.

The contamination has also endangered the biodiversity of the river, killing birds, fish, and plants.

Damascene Gashumba, a researcher said: "Some species such as birds are no longer visible yet we used to observe them in nature around the rivers. Waste discharged into Nyabarongo and Akagera Rivers have led to the loss of biodiversity such as fish and frogs among many others.”

Challenges hampering protection of Nyabarongo River

At least 51per cent of the people in the local community, the study found, are not involved in the protection of the river. 24 per cent said they were financially constrained while 23 per cent lacked the skills in river protection.

The study recommends the establishment of a catchment management plan, more terraces and planting trees, law enforcement in protecting the buffer zone as well as increased inspections to fight encroachment.

It also recommends education and awareness about conservation in the community and further research to provide more data about the pollution of Nyabarongo based on each causal agent for its pollution.

The river begins its course at the confluence of Mbirurume and Mwogo Rivers in southwestern part of the country.

The river serves as the boundary between the Northern and Southern Provinces, then between the City of Kigali and the Southern Province as well as between the City of Kigali and the Eastern Province.