ARUSHA: THE effect of chemical flow in Lake Victoria poses a great threat to its biodiversity, affecting aquatic life and the ecosystems around it, according to the latest study conducted by Bethany International.
Bethany International Director Jimmy Pamba said recently in Arusha that the study focused on checking the effects of chemical flow in Lake Victoria on biodiversity.
The study revealed that such chemicals originate from agricultural activities, industrial waste disposal, unregulated sewage and the growth of cities and villages along the shores of Lake Victoria.
These chemicals, including fertilisers, pesticides, heavy metals such as iron, zinc, lead and mercury which are part of industrial pollution, adversely affect the lake’s water quality and ecological balance.
Runoff from agricultural fields often carries high levels of nitrogen and phosphorus from manure and animal waste. When these nutrients enter Lake Victoria, they can cause the decomposition of nutrient-rich fertilisers, where many nutrients contribute to the rapid growth of algae (algae).
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The study explains that when the algae die and decay, they consume a large amount of oxygen, resulting in a low oxygen level that cannot satisfy fish and other aquatic organisms and thus slip the effects of life in the Lake Victoria.
“Some species of algae produce toxins that can poison fish, other marine life and even humans. These blooms reduce the quality of water and can cause death of aquatic life,” he said.
Mr Pamba noted that agricultural and industrial runoff can introduce harmful substances such as pesticides like DDT and heavy metals like Mercury and Lead into the lake. These chemicals accumulate in the food chain and can be toxic to aquatic life.
The study explains that over time, toxins like mercury accumulate in the tissues of fish and other organisms, thus affecting their reproduction, growth and survival and the situation can lead to a decrease in the number of fish, which is the main source of food and income for the local communities.
Chemical pollutants can alter the physical and chemical characteristics of lake habitats. For example, the introduction of toxic chemicals can change the acidity and alkalinity of water, affecting their evolution.
A combination of factors such as toxic chemicals, decreased oxygen levels and habitat destruction can lead to the decline or even extinction of certain species, especially those that are endemic to Lake Victoria, such as cichlid fish and create vulnerability or threat to tilapia, Nile perch, African lung fish, Lake Victoria snails and Oysters and endemic plants.
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Chemical poisoning can cause a decline in fish populations, which affects local fisheries. More than 30 million people depend on Lake Victoria for fish and depletion of fish stocks can have significant economic and social impacts.
Chemical pollutants, especially heavy metals and pesticides, can make fish unsafe for human consumption, posing a risk to public health.
The study says people who depend on the lake for drinking water, agriculture, or fishing can face serious health problems due to drinking or eating contaminated water or fish respectively. Pesticides and industrial chemicals can cause long-term health effects, such as cancer and neurological diseases.
Damage to the lake’s ecosystem can lead to loss of livelihood for those who depend on the lake’s resources. Depletion of fish stocks and polluted water can affect the local economy and food security.
In order to reduce the risks, several measures can be taken as shown in the study which are to promote sustainable agriculture with the correct use of fertilisers and pesticides, along with agroforestry methods, which can help reduce the flow of nutrients.
The study emphasised that strengthening industrial regulations and improving the management of urban waste and sewage can help prevent harmful chemicals from reaching the lake as well as protecting and restoring wetlands around the lake which can act as natural filters, reducing the flow of harmful chemicals into the water.
Thus, chemical runoff in Lake Victoria poses a serious threat to biodiversity, endangering aquatic life, local livelihoods and human health. Urgent measures are needed to reduce environmental pollution and restore ecological balance.
