Pollution takes toll on Lake Victoria

Efforts. Researchers collecting samples of water from Kisumu Resort on the shores of Lake Victoria in Kisumu, Kenya. PHOTOS BY RACHEL MABALA

What you need to know:

  • For three months, Nation Media Group and scientists from University of Nairobi combed different parts of the lake from Tanzania, Kenya, and Uganda. In Part One of the series, their findings
    indicate that heavy metals, pesticide and faecal matter threaten the lake.

As you sit at home or in a hotel, drinking that glass of water, you could be putting your life at risk since some of it, whose source is Lake Victoria, may be contaminated.

For more than three months, a combined team of NMG journalists from Uganda and Kenya, accompanied by scientists from University of Nairobi, combed different parts of the lake right from the border with Tanzania down at Rakai where Kagera River pours it dirty waters into the lake, to Kenya where the lake faces stark reality of rotting from the deep. A total of 52 samples were picked from 28 spots across the two countries.

Led by Prof James Mbaria, the chairperson of the Department of Public Health and Pharmacology Technology at University of Nairobi, the team found out that Lake Victoria and a number of rivers that either drain their waters from the lake or pour it into the lake are heavily contaminated with heavy metals, pesticides and other microbial organisms that have adverse effects on human and aquatic life.

Fish, water and sediment samples taken from different spots both in Uganda and Kenya showed that they contained pesticides and other pollutants that are hazardous to human beings. In Uganda, fish samples were taken from Ggaba in Kampala and Masese Landing Site in Jinja.

Water and sediment samples were taken from Nakivubo Channel that drains into the lake and from the Source of the Nile in Jinja. The rest of the samples were taken from the Kenyan side of the lake and the rivers that drain water into the lake.

The results of the analysis showed the presence of microbiological and chemical contaminants at the various sampling points across the lake.

According to the results, total coliforms and Escherichia coli counts, which are useful in determining the bacterial quantity of effluent discharged to the environment, were present.
Their presence in water is, therefore, an indication of the possibility of there being other highly pathogenic micro-organisms transmittable through faecal contaminated water.

The presence of coliforms and Escherichia coli could be explained by the fact that many of the islands and landing sites on Lake Victoria have very poor sanitation, with dwellers discharging raw sewage in the lake.

Various factories and other facilities near the lake are also known for discharging effluent from their facilities right into the lake, further polluting the waters. The situation has not been helped by degradation of wetlands, mostly by investors who set up factories and other businesses in the wetlands that used to act as natural filters.

When our reporters visited different landing sites, the sanitary facilities were wanting. At Luzira and Ggaba, dirty refuse from the city ends up in the lake through Nakivubo channel, with all the impurities from the city.

At Kasensero Landing Site in Rakai District, dirty water pours into Lake Victoria from Kagera River. There is a clearly visible difference in colour of the water from Kagera pouring into the lake.

Residents at the landing site say huge deposits of impurities brought to the lake by the river pose great health risks to them. Across the Lake at Lukunyu Landing Site, residents deposit faecal matter in the water. Fishermen who spend days in the lake defecate in the lake. Even water borne toilets on the island discharge faeces in the lake when it rains.

Effects. A man fetches water at Kasensero Landing Site in Rakai District. Study.

Mr Joshua Mununuzi, a businessman at the landing site, say the situation is horrible. He says the locals are not sensitised about sanitation and all they know is defecating in the lake, which pollutes the waters.

“People defecate in the polythene bags and throw them in the water, which causes pollution. On top of that, the fishermen who go into the lake spend days in the water and just defecate in the lake. Even people use condoms and throw them in the lake. Those toilets are water toilets and these people open them when it is raining and release the raw sewage into the lake,” he said.

Prof Mbaria says the findings show that both the water and fish from the lake may not be safe for human consumption and the aquatic life.

“Lake Victoria is contaminated with both the living organisms that cause disease and chemicals that cause poisoning, they can cause acute and chronic problems. The water in the lake is not safe; the fish is also not safe in most areas but that can be improved through control of pollution,” Prof Mbaria says.

He says now is the time to act. According to him, a number of interventions, including review of policies and attitude change, can save the situation.

“What we can do is to first have behaviour change and then even the policies that are there need to be revised,” Prof Mbaria says.

“For example, if you are to treat the effluent before it goes into the lake, I am sure there are some organisations charged with doing that. Are they sleeping on their jobs? We need to find out what is the root cause, then people need to take up their responsibilities,” he adds.

In Namayingo District where artisanal mining is taking place, local veterinary officials have reported strange diseases in livestock. The miners there use mercury to purify gold, which eventually ends in the lake.

Mr Peter Wambuzi, who has lived in the area for more than 50 years treating animals, says animals that drink from the lake near the point where artisanal miners operate are affected by strange diseases. He attributes this to use of mercury that eventually finds its way into Lake Victoria. “What I am seeing this time is different. The animals start rotting when they are still alive and it only stated after gold mining started in the area,” Mr Wambuzi says.

Heavy metals
According to the findings, there were traces of heavy metals detected in all the five fish samples tested during phase one and two both in Uganda and Kenya, including lead detected at levels above CODEX (FAO/WHO) permitted maximum residue levels. The heavy metals include lead, cadmium, chromium, zinc, iron, copper and manganese.

The report notes that while all the fish samples tested had at least six different types of heavy metals detected at levels lower than the WHO recommendation, those sampled in the second phase from Uganda, Kenya and China had lead at levels far above the CODEX recommended residue levels of 0.1ppm.

The same fish samples had relatively high levels of zinc though below the CODEX of 30ppm. Sediments, on the other hand, had seven heavy metals, with none having mercury. There are no guidelines available for concentrations in sediment.

Up to 21 different pesticides, including organochlorines, organophosphates and pyrethroids, were detected at different concentrations and frequencies in the water samples.

While the World Health Organisation evaluation scheme programme approves pesticides for direct application to drinking water for control of insects, the report says some of the pesticides found in the samples from the Lake Victoria basin and its catchment rivers are of known toxicity to both humans and aquatic life.

The samples include Fenitrothion, an organophosphate used as insecticide and is toxic to aquatic life; chlorofenvinphos, which affects the respiratory system in humans; and cyhalothrin, which has been shown to cause irritation of the mucous membrane.

Others are bifenthrin, which is harmful to aquatic life and has been classified as a human carcinogen, capable of causing cancer. Also found is Oxyfluoren, which is used to kill broad leaf and grassy weeds.

The results also show that some of the globally banned pesticides with advance effects on humans and aquatic animals, including DDT and its metabolite, endosulfan and mirex, were detected in some of the water samples. In sediments, 25 different pesticides were detected at varying concentrations and frequency.

“A few of the pesticides detected in the water and other samples have been globally banned due to their toxicity and environmental persistence. These include DDT, which is highly persistent in the environment, is very soluble in water, affects reproduction in humans and has been classified as a possible human carcinogen,” the report says.

Endosulfan, which was globally banned in 2012, is an insecticide and a known neurotoxic that causes birth defects. Another banned pesticide detected was mirex, which is also a bio accumulator and persists in the environment as a persistent organic pollutant thus affecting aquatic life. It is carcinogenic with potential to cause cancer and an endocrine disruptor.

Study. Researchers collect samples from a sugar factory in Kisumu on the shores of Lake Victoria in Kenya.

The research findings showed that 25 different types of pesticides were detected in sediments at varying concentrations and frequencies in the study area, though mostly on the Kenyan side.
The most frequent pesticide detected in fish was pyridaphenthion at 4/5 (80 per cent) while linuron, pyrazophos and cypermethrin were each detected in three out of five (60 per cent) fish samples.
Homa Bay in western Kenya had the highest level of pesticides 10/19 (53 per cent) contaminating the fish samples, followed by fish obtained at Ggaba Landing Site in Kampala at 11/22 (50 per cent) while fish from Sondu in Kisumu had 42 per cent (8/19) pesticides. Officials from the Ministry of Water and Environment that are charged with responsibility of protecting Uganda’s environment refused to offer interview on the implications of the findings of the research. The same was with the National Environment Management Authority (Nema), whose officials also refused to respond to the issues in the research findings.
Our team of reporters spent the whole of January trying to fix interviews but all the officials declined, even after the management presented official requests for information to the Nema Executive Director, who said he was on leave. A source at the authority, who spoke on condition of anonymity, said there was a decree that it should only be the executive director to respond to the media inquiries.

Govt speaks out
At the Ministry of Agriculture, Animals Industries and Fisheries, officials dismissed the findings and said they have been carrying regular tests on the fish from Lake Victoria and their findings show that Uganda’s fish is still safe.

Ms Joyce Ikwaput, the assistant commissioner for fisheries, told NMG Uganda that they have carried out a number of tests both on the fish and waters and found no risks. She also said another report is expected next week, confirming the safety of Ugandan fish for consumption.

“The fish in Lake Victoria is still safe, it is still safe as far as human consumption is concerned. We have been carrying out tests for more than 10 years on our fish. We test on the water, we do tests on the fish and sediments and we have not found the levels,” she said.

Ms Ikwaput, however, said while small portions of metals and other dangerous chemicals and pesticides have been found in the sediments, they are below the WHO permissible levels.

“There were some levels on the sediments but still below the maximum risk levels but on the fish, it was still safe. Even our factories are doing tests every two months and the fish is safe,” she said.

“We have picked samples from those areas and we have submitted them and we expect the results next week or the other week to reconfirm because we have to submit this to EU also to show that our fish is safe for human consumption,” Ms Ikwaput added.

In the second part of the series tomorrow, we delve into the cost of making water from Lake Victoria safe for human consumption as pollution takes toll.