The Tanzanian territory embraces a wide variety of landscapes, including mountains, savanna, bushlands and forests. Some 53,000 square kilometres of the country comprises lakes, being Lake Victoria the biggest one. With an area of 69,490 square kilometres Lake Victoria is the world's second largest freshwater lake. It is an essential resource for the life of the surrounding region, which has one of Africa's highest population densities. Farming, fishing and boatbuilding are the most significant economic activities that directly depend on the lake.
The ecological health of Lake Victoria has been deeply affected by a combination of degrading processes of different nature, such as the clearance of natural vegetation along the shores, a booming fish-export industry, the disappearance of several fish species, the eutrophication of the water body, and the dumping of untreated effluents by several industries. Traditional lifestyles of lakeshore communities have been disrupted and it is feared that together with the degradation of the lake they could disappear.
This sad story goes back to the first decades of the 20th century, when the British colonialists started to exploit Lake Victoria's watershed, and continued after the political independence of the country in 1963. During colonial times the surrounding forests were cut down, and the swamps that were part of this complex hydrologic system drained. Cash crops, such as tea, coffee and sugar, were planted instead. Over the years they have grown in size and number. Since these crops are based on Green Revolution agriculture, a significant portion of the chemicals used are washed into rivers during the rainy season, and end up in the lake, causing eutrophication and providing nutrients for algae bloom, which completely alters the dynamics of the whole water body.
The exagerated growth of the economic activities in the lake and its surrounding area has overcome the carrying capacity of the ecosystem. Not only the surrounding lands but also the water body in itself is subject to overexploitation. With the introduction of modern fishing methods, overfishing has become a problem and catch sizes have dropped. A survey of the lake carried out in 1980 revealed a total reverse in biomass composition. As a consequence the populations of smaller fish, which traditionally have been the source of livelihood for nearby communities, have been decimated by larger predators and overfishing.
Polluting industries --from textile and leather-tanning to paper mills and breweries-- located near the lake, constitute another cause for the present situation. A recent study shows that industrial plants located in the Tanzanian territory produce daily two million litres of untreated sewage and industrial waste that flow into the lake.
To add to the problem, last June a new and extremely polluting activity began in the region: gold mining. The companies involved are Ashanti Goldfields of Ghana and AngloGold of South Africa. Tanzanian President Benjamin Mkapa himself, who inaugurated the Geita Gold Mine, the biggest one in East Africa, located 20 kilometres away from the southern shore of Lake Victoria, even pledged more incentives for investments in the sector.
Environmentalists from Tanzania and Uganda have clearly expressed their opposition to gold mining, and warned that there is a high risk that sodium cyanide, a strong poison used to extract gold from ore, might leak into the lake through the rivers and cause an additional negative effect to the already affected water system. Concerned voices from the academic sector in both countries have also harshly criticized the Tanzanian government for supporting a project that would jeopardize the environment of the lake and the lives of communities living around it. I has been underscored that mining in the region will also bring negative consequences for the region and the country's economy, since the European Union is about to ban all fish imports from East Africa because of the presence of toxic elements in the fishes' bodies.
Article based on information obtained from: Drillbits & Tailings, Volume 5, Number 15, 19/9/2000; "Lake Victoria: a sick giant" by Nancy Chege, The Worldwatch Institute