The Ministry of Water and Environment has explained that the foul smell recently reported along parts of Lake Victoria is caused by persistent algal blooms resulting from increased pollution in the lake’s bays, particularly the Inner Murchison Bay.
“The foul smell is a result of excessive algal growth driven by high pollution levels in the bays,” the Ministry said in a statement, noting that Inner Murchison Bay has been the most affected.
Several members of the public have complained of an unsual smell coming from Lake Victoria, with many raising their fears about safety of the water anf fish from the lake.
In a statement on Tuesday, the Ministry of Water explained that the Inner Murchison Bay is one of the most heavily utilised sections of the lake in Uganda.
“The bay is shallow, less than 10 metres deep, and sheltered from the open lake, which makes it especially vulnerable to pollution,” it explained.
Other bays experiencing similar pressure include Kitubulu and Nakiwogo in Entebbe, as well as Napoleon Gulf in Jinja.
According to the Ministry, these bays receive heavy pollution loads from their surrounding catchments.
“The pollution comes from surface runoff carrying silt, human and plastic waste, municipal wastewater from nearby suburbs, industrial effluent, and runoff from agricultural fields,” the Ministry said.
It added that the situation has been worsened by wetland degradation, noting that “wetlands previously played a critical role in filtering nutrients and trapping suspended organic matter before water entered the open lake.”
To track changes in water quality, the ministry said it operates a dedicated Water Quality Monitoring Network with 23 monitoring stations in Inner Murchison Bay and 10 in Entebbe Bay, "with samples collected quarterly to guide policy decisions and remedial actions."
According to the ministry, data from the monitoring network shows a persistent increase in nutrient concentrations, particularly nitrogen and phosphorus.
“These nutrients are essential for algal growth, and their increasing levels have led to frequent algal blooms in the bays. The recent dry season and high temperatures intensified the blooms when water mixing occurred.”
The ministry explained that the unpleasant odour arises when algae die and decompose.
“During decomposition, algae consume oxygen and release gases such as hydrogen sulphide and ammonia, which cause the foul smell,” it said.
"Reduced oxygen levels in the water are harmful to aquatic life and can lead to fish kills,” adding that decomposing algae also release nutrients back into the lake, “creating a vicious cycle of recurring algal growth.”
The stench, it noted, has been most pronounced around Inner Murchison Bay in Luzira and parts of Entebbe.
They however said, several interventions are already underway to address the problem.
“We are restoring degraded wetlands, enforcing the 200-metre buffer zone around the lake, strengthening water quality monitoring, and scaling up enforcement of effluent discharge standards,” the ministry said.
The ministry also noted that industries are being supported to adopt cleaner production techniques and that public awareness campaigns on lake protection are ongoing.
However, they acknowledged that these efforts must be intensified.
“Solid waste management around the lake and its catchment needs to be prioritised to reduce nutrient inflows,” it said, while also calling for “stronger enforcement of environmental and public health regulations by urban authorities.”
"Environmentally friendly land-use and agricultural practices must be promoted, and more industries must adopt cleaner production methods.”
They noted that algal blooms will persist unless pollution entering the lake is significantly reduced.
“Protecting Lake Victoria requires coordinated action among local communities, government institutions, urban authorities, and environmental organisations. The protection of Lake Victoria is a shared responsibility, and saving this vital resource requires the commitment of every Ugandan."
