- In July 2021, an Angolan diamond mine leaked large amounts of polluted water into the Kasai River Basin which stretches across Angola and the Democratic Republic of Congo.
- Twelve people were killed, a further 4,400 fell ill and an estimated 1 million more were affected by the polluted water.
- Fourteen months later, the DRC government has not released full results of tests conducted on the rivers, but a ban on drinking the water from the Kasai and Tshikapa rivers remains in place.
- An independent report published in September 2022 has found that the leak killed off much of the rivers’ aquatic life, with severe and ongoing impacts on river-dependent communities.
The July 2021 rupture of a tailings dam at a diamond mine in Angola killed off much of the aquatic life in the Lova, Tshikapa and Kasai rivers. Twelve people are known to have died after exposure to the polluted water. A new report by the International Peace Information Service (IPIS), an independent research institute, says the spill at the Sociedade Mineira de Catoca mine has had long-lasting negative impacts on river-dependent communities downstream in Angola and the Democratic Republic of Congo.
When the dam ruptured on July 27, 2021, it sent large volumes of mining waste into the Lova River, which spread quickly into the Tshikapa and Kasai rivers, turning them red for hundreds of kilometers downstream.
IPIS analyzed media coverage and official statements by Catoca and the Angolan and DRC governments, as well as reports from local nonprofit organizations, members of parliament, and academic researchers. It concluded that the mine and both governments have kept the public in the dark about what exactly leaked into the rivers, killing thousands of fish and leading to a ban on fishing in the rivers and extracting water that is still in place 14 months later.
Catoca took water samples in 2021 and said the water that escaped its dam contained only natural rocks and clay. “To the layman, this does not seem to be a problem. However, the determination ‘sand and clay’ says nothing about the chemical composition of such particles,” the IPIS report says.
While the DRC government ran its own tests of water quality, it hasn’t published the full findings, with the country’s environment minister, Ève Bazaiba, only announcing initially that preliminary results of tests in the Kasai River showed the presence of iron and nickel, IPIS says.
It was left to the Unit of Toxicology and Environment at the University of Lubumbashi in the DRC and the Department of Public Health and Primary Care at the Catholic University in Leuven, Belgium, to independently test the water quality. Their tests also found iron and nickel, but revealed that the rivers were additionally contaminated with uranium, according to the IPIS report.
![The Mayi Munene waterfall](https://imgs.mongabay.com/wp-content/uploads/sites/20/2022/10/04120855/Mayi-Munene-waterfall.jpg)
The DRC government initially demanded reparations from the mine, but these do not seem to have been paid or even seriously discussed, IPIS says. Although an announcement was made by both the DRC and Angolan governments that bilateral meetings would be held to get to the bottom of the spill, these consultations “were never heard of again.” The IPIS report says the Angolan government stymied an investigation into Catoca at the behest of the DRC.
In the more than a year since the incident, the DRC government has also failed to fulfill a promise to construct 30 new water wells for the communities living on the banks of the Kasai and Tshikapa rivers. The report adds that 200 villages and almost 1 million inhabitants in the DRC have been affected because they rely on the rivers for 80% of their total water supply.
“Nothing has been done up till now,” DRC MP Guy Mafuta told Mongabay in a phone interview. “People [affected by the pollution of the river basin] have been left to fend for themselves.”
Parliamentary questions from Mafuta asking for environmental impact assessment results and water and sediment analyses have not been answered, and while Mafuta later organized 8,000 affected people to launch a lawsuit against the Angolan government, “it remains to be seen whether a Congolese tribunal can enforce anything against an Angolan company” the IPIS report says.
Indifference follows negligence
The Catoca mine is the fourth-largest diamond mine in the world, majority owned by a joint venture between Angolan state-owned Endiama and Russian state-owned Alrosa.
Neither the mine nor the Angolan government immediately disclosed the tailings dam rupture when it happened in July 2021. It was only thanks to satellite photos that the pollution was tracked from the DRC back to the SMC tailings dam in Angola.
The University of Kinshasa-based Congo Basin Water Resources Research Center described the leak at the time as an “unprecedented environmental catastrophe.”
At the time, the center urged extensive sampling of water quality, sediment, and aquatic biodiversity to determine if the damage from the pollution had spread beyond the immediately visible areas. However, a shortage of funding meant it couldn’t visit the site to see if the governments had carried out any testing or remediation.
Both Endiama and Alrosa told Reuters a few days after last year’s leak was spotted that it was not their responsibility to inform the public that the tailings dam had ruptured.
![The Kasai River in DRC.](https://imgs.mongabay.com/wp-content/uploads/sites/20/2022/10/04121151/Sunset_view_from_Kalonda-2.jpg)
Alrosa also has a deal with the Zimbabwean government to prospect for diamonds in that country. In late September this year it announced that it had discovered 22 new diamond deposits in Zimbabwe, two of which it will be given to mine itself.
“Angola does not have a convincing track record when it comes to protecting the rights of communities affected by diamond mining,” the IPIS report says. “The Angolan government and the Sociedade Mineira de Catoca are unlikely to assume any responsibility towards the Congolese victims, while the Congolese government is culpably negligent.
“The only response the hundreds of thousands of Congolese affected by the Catoca mine pollution have felt to date, is the still prevailing prohibition on consuming water and fish from the Tshikapa and Kasai rivers. The inaction by Congolese authorities and failure to provide clean water supplies and relief measures makes the Kasaian population twice a victim. Meanwhile, the world has forgotten yet another crisis in a remote and impoverished area of Congo,” the report concludes.
“I have initiated a legal action,” Mafuta said, but added it has faced complications. The legislator said he’s spent $15,000 of his own money to bring the lawsuit against Catoca, but in addition to uncertainty about prosecuting a foreign company in the DRC’s court system, a series of delays due to clumsy management of court processes has effectively forced Mafuta to launch the lawsuit afresh.
“We have to start from zero, which also means new costs, all while the victims have not received any support,” he said.
Contacted by Mongabay, the environment minister said she could only comment on this matter after the conclusion of the pre-COP 27 meeting she is hosting in Kinshasa from Oct. 3-5.
Sylvain-Gauthier Kabemba contributed to this report from Kinshasa.
Toxic spill at Angola diamond mine pollutes Congo River tributary in DRC
Banner image: People wait on the Kasai bank to cross the river. Image by Terese Hart via Flickr (CC BY-NC-SA 2.0).
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