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Toxic spill at Angola diamond mine pollutes Congo River tributary in DRC

Pirogues on the Kasai River with forests on the far bank. Image by Terese Hart via Flickr.

Pirogues on the Kasai River in DRC. Image by Terese Hart via Flickr (CC-BY-NC-SA-2.0).

  • In early August, toxic substances from three diamond-processing facilities in neighboring Angola polluted the Kasai River, a major tributary of the Congo.
  • Researchers fear there could be severe and lasting consequences for the environment and people’s health in affected areas in the Democratic Republic of Congo.
  • The polluted water is moving toward Kinshasa, the capital, according to the DRC’s minister for the environment and sustainable development.

On Aug. 12, authorities in the Democratic Republic of Congo’s Kasaï province noticed the Kasai River had turned red. Witnesses said the bodies of hippos and dead fish were seen floating in the river.

“We have taken samples of water, fish, and bones from dead aquatic animals and sent them to the veterinary lab of Kinshasa to determine what substance is threatening the ecosystem,” said the governor of Kasaï, Dieudonné Piemé.

The pollution was first detected in a tributary of the Kasai River, the Tshikapa, which rises from headwaters in Angola before flowing through the provincial capital that bears its name. The Kasai itself is a tributary of the Congo River.
According to Governor Piemé, the pollution originates from a major spill at three mining facilities across the border in Angola: Camaxia-Camagico, Luo et Catoca.

“We were concerned to trace the source of this problem and we were able to go back towards the province of Lunda Sul in Angola,” the governor said. “A facility for processing diamonds suffered an operational failure serious enough to spill toxic materials into the river on that side [of the border]. This led me to contact my colleague, Ernest Muangala [governor of Lunda Norte] in Angola, and we discussed the situation with him and discovered that there had been an operational accident at a well-known business, and this led to the pollution of the river and the threat to aquatic animals.”

Researchers at the University of Kinshasa’s Congo Basin Water Resources Research Center (CRREBaC) are concerned about major consequences, particularly the potential for lasting contamination of groundwater.

“There is a fear of the possible consequences, notably the poisoning and loss of aquatic plants and animals, of waterborne illnesses for communities in the area, disturbance of fishing activities and navigation, and a lack of access to water for domestic use and recreation,” said Raphaël Tshimanga, director of CRREBaC.

Tshimanga said that thorough studies would be carried out as soon as possible to better understand the situation with the water table after this pollution incident.

The health of people living on the banks of these rivers is also in danger. Communities were using this water right until the announcement of the contamination. Some also ate dead fish and animals that were floating in the river.

The environment ministry reported that more than 400 people had reported diarrhea after using contaminated water. The ministry said 13 of the province’s 18 health districts have been affected, potentially exposing more than 950,000 people.

According to Ève Bazaiba Masudi, the DRC’s minister of the environment and sustainable development, the pollution in the river is moving toward Kinshasa, the country’s capital.

“It’s no longer in Kasaï alone. Tomorrow or the day after, we will find these substances here in Kinshasa, in the Congo River,” she said.

The government is planning both humanitarian and diplomatic action. The foreign affairs and environment ministers are expected to visit Angola shortly to determine precisely the source of the pollution and establish who was responsible. This followed a formal diplomatic note verbale from the Congolese government to the authorities in Luanda.

“Humanitarian aid is needed for communities along the river,” Bazaiba said. “A high-level team will soon be on the ground on a solidarity mission, a humanitarian mission covering the entire region.”

Congolese experts believe the Congo River itself could play a “self-purifying” role. But traces of the toxic spill have already been seen several kilometers from Kasaï, according to hydroclimatologist Modeste Kisangala Moke.

This story was reported by Mongabay’s French team and first published here on our French site on Aug. 28, 2021.

Banner image: Pirogues on the Kasai River with forests on the far bank. Image by Terese Hart via Flickr (CC-BY-NC-SA-2.0).