What's causing the foul smell coming from Lake Victoria?

For a waterbody that serves millions of people, an unbearably foul smell coming from Lake Victoria lately has undoubtedly cringed noses and raised eyebrows.

Amid mounting concerns over the unpleasant smell, the water and environment ministry has spoken out on what's happening to Africa's largest freshwater lake.

In a statement released on Friday (April 4), water and environment minister Sam Cheptoris said the government is actively addressing the awful odour coming from the lake.

It is being pointed to increased pollution, particularly the dumping of waste along the lake’s shoreline.

A vital resource for Uganda and the region, Lake Victoria serves over 38 million people by providing drinking water, facilitating transportation, and supporting local trade and businesses.

The Lake Victoria basin is home to key natural resources, including fish, water, biodiversity, land, and minerals.

Murchison Bay, the most heavily used shoreline area of the Ugandan part of the lake, is particularly shallow (mostly under 10 metres) and sheltered from the open lake. 

However, this bay also receives a high volume of pollution from various sources, including silt-heavy surface runoff, human and plastic waste, municipal wastewater from Kampala and nearby suburbs, and industrial waste. 

The ministry said the degradation of wetlands, which would typically filter out these contaminants, has only worsened the situation.

Hydrogen sulfide gases

The ministry said it operates a water quality monitoring network in Murchison Bay, with 21 monitoring stations in Kampala and 10 in Entebbe. 

This network tracks water quality to assess the lake’s capacity to support aquatic life. 
Quarterly data collected from these stations informs policy decisions and helps direct remedial actions aimed at mitigating water resource degradation.

The ministry said the research has shown a "troubling, persistent increase in nutrient levels in the bay", which creates ideal conditions for algae growth. 

Algae thrive on these nutrients, leading to the greenish coloration of the water. 
"When algae die and decompose, they release ammonia and hydrogen sulfide gases, which contribute to the foul odour (akin to a rotten egg smell) and create hypoxic conditions that harm aquatic life. 

These odours intensify during windy conditions and high temperatures.

Way forward

The water and environment ministry outlined immediate actions to combat the issue.
One of them is restoration of degraded wetlands.

It said the restoration of wetlands and the protection of a 200-metre buffer zone around the lake, as stipulated by the Environment Management Act, is critical to preventing pollutants from entering the water.

Improved waste management will also help.

Effective solid waste management, wastewater treatment, and better agricultural practices are essential to limit the influx of nutrients into the lake, the ministry said.

Additionally, industries must adopt cleaner production methods to minimize wastewater discharge into the lake.

The ministry also said urban authorities need to enforce environmental and public health regulations to control waste entering the lake.

"There is a need to increase civic education among communities living along the lake to foster a sense of ownership and responsibility in protecting Lake Victoria from further pollution," the ministry added.

These actions, the ministry said, require coordinated efforts from local communities, government ministries, urban authorities, and environmental organizations "to restore and maintain the ecological balance of Lake Victoria".

Minister Cheptoris urged all Ugandans to take part in efforts to protect the lake and its valuable ecosystem.