Lake Tanganyika, Africa’s deepest lake, is facing a high risk of pollution and significant decrease in water levels as authorities call for urgent action to save its ecosystem.
Located in the western branch of the great African Rift Valley, the lake divided among four countries: Tanzania, the Democratic Republic of Congo, Burundi, and Zambia. It is one of the oldest lakes in the world, probably dating back about 10 million years.
The lake, shared by four countries – Burundi, Democratic Republic of Congo (DRC), Tanzania and Zambia — is a source of food, drinking water, transport and many other amenities to millions of people who live around the lake basin and beyond.
However, the lake has been affected by the industrial pollution that has been given little or no attention.
“The Burundi institute in charge of treatment of waste water is facing a serious technical problem, currently the pump that is to pump waste water from the industries to the treatment station before being released to the lake sometimes doesn’t function forcing the water from the industries to go directly to the lake before being detoxicated,” said Emmanuel Ndorimana, the general director, water and sanitation, in Burundi’s Ministry of Environment.
One of the many factories surrounding Lake Tanganyika is the African Tannery.
The director-general, Bede Bedetse, however said that the company is under the government Setemu institution, responsible for treating waste water before it is released into the lake.
“The problem is the Setemu pump that doesn’t function, so when we release the waste water it diverts straight to the lake before being detoxicated,” said Mr Bedetse.
Residents around the lake complained about the unprotected trench which produces an unpleasant smell all day.
“We raise the issue with the local administrators during the local meetings but nothing is done,” said a resident.
Bucumi Masumbuko, a fisherman, said: “There is scarcity of fish in the lake two years ago we used to get three 20-litre basins full of fish but now we only get one and sometimes half a basin,” he said.
However, the government of Burundi introduced a law that protects water bodies and allows the construction of private buildings only beyond 150 metres away from the lake.
“The space of 150 metres is used for the plantation of trees, but only those who got special authorisation can build near the lake,” said Mr Ndorimana.
Standing on the steep rocky shores of Lake Tanganyika at sunset, looking out at fishermen heading out for their nightly lamp-boat fishing trips, it’s easy to imagine this immense 32,900 square kilometres of water as serene and unchanging.
That expanse of geological time has permitted literally hundreds of unusual species of fish and invertebrates to evolve in isolation — organisms that are unique among the world’s lakes. Every day millions of people rely on the lake’s riches.
But despite being a world class reservoir of biodiversity, food and economic activity, the lake is changing rapidly and may be facing a turbulent future.
Threatened lake of 2017
Lake Tanganyika was recently declared the “Threatened Lake of 2017” — adversely affected by human activity in the form of climate change, deforestation, overfishing and hydrocarbon exploitation.
Beginning in the late 1980s, scientists studying the lake began to notice significant and concerning changes caused by human activity.
But at the time, worldwide attention was focused on their other African Great Lakes, particularly Lake Victoria, where evidence was beginning to emerge of the enormous impact the Nile Perch — an introduced species — was having.
The problems in Tanganyika were somewhat different.
Fortunately, no major exotic species introductions have occurred up to now. Instead, evidence shows that underwater habitat degradation is taking place adjacent to hill slopes. They are being rapidly deforested – converted to agricultural lands or for urban expansion — in the fast growing population centres around the lake. This activity has led to a rapid increase in the amount of loose sand and mud being washed into the water, is smothering the lake floor.
The biodiversity of Lake Tanganyika can be imagined like a thin bathtub ring. It hugs the shallow zones around a deep and steep bottomed lake, up to 1,470 metres in its deepest parts. The hundreds of species that inhabit the sunlit shallows give way to a dark expanse of water lacking oxygen and, so, animal life.
This narrow strip of extraordinary biodiversity is on the frontline. Eroded sediments are being carried into the lake, affecting this strip.
Researchers have begun to document where the impact is being felt. They are also looking back in time by collecting sediment cores with fossils of the many endemic animals to see when the impact was first felt.
They have found that some heavily populated regions lost much of their diversity more than 150 years ago. Other regions, particularly in the more southerly past of the lake, are seeing these effects unfold only in recent decades.