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Scientists at KU Leuven, University of Lubumbashi reveal the health risks of cobalt mining in DR Congo

Demand for cobalt has been on the increase due to its many applications. The metal is a crucial component of rechargeable lithium-ion batteries for smartphones and electric cars. Around 60% of the world’s cobalt supply comes from the mineral-rich Katanga Copper belt, in the Democratic Republic of the Congo.

Researchers at KU Leuven and the University of Lubumbashi have now shown that cobalt mining takes a high toll on both the creuseurs—the ‘diggers’ who work in the mines, often by hand—and on the environment. Their paper is published in the journal Nature Sustainability.

Previous research by KU Leuven and the University of Lubumbashi (2009) had already found high concentrations of trace metals in the urine of people living close to mines. The new works confirms the health risks of cobalt mining.

The researchers conducted a case study in Kasulo, an urban neighborhood in Kolwezi, in the heart of the Congolese mining area. When cobalt ore was discovered under one of the houses there, the entire area quickly became an artisanal mine. The houses are now interspersed with dozens of mine pits where hundreds of creuseurs hunt for cobalt. Most residents remained in the area.

The major problem is the dust containing cobalt and many other metals, including uranium that is released during the mining process and settles on the ground.

The houses in Kasulo are now interspersed with dozens of mine pits where hundreds of creuseurs hunt for cobalt. Most residents remained in the area.

The researchers collected blood and urine samples from 72 Kasulo residents, including 32 children. A control group with a similar composition was selected in a neighboring district.

Children living in the mining district had ten times as much cobalt in their urine as children living elsewhere. Their values were much higher than what we’d accept for European factory workers. This study may be limited in scope, but the results are crystal-clear. The differences cannot be attributed to coincidence.

—Professor Benoit Nemery, doctor-toxicologist at the KU Leuven Department of Public Health and Primary Care

The long-term consequences of this increased exposure to cobalt are not yet clear, but Professor Nemery is not optimistic.

Cobalt is less toxic than other metals such as lead, cadmium, or arsenic. But we found increased concentrations of several other metals as well. Furthermore, we found more DNA damage in children living in the mining area than in those from the control group. And the preliminary results of an ongoing study suggest that miners’ new-born babies have an increased risk of birth defects.

—Benoit Nemery

Simply banning artisanal mining in the DRC is not a good option because the industrial mines usually leave a lot to be desired as well.

This field study provides novel and robust empirical evidence that the artisanal extraction of cobalt that prevails in the DR Congo may cause toxic harm to vulnerable communities. This strengthens the conclusion that the currently existing cobalt supply chain is not sustainable.

—Nkulu et al.


  • Célestin Banza Lubaba Nkulu, Lidia Casas, Vincent Haufroid, Thierry De Putter, Nelly D. Saenen, Tony Kayembe-Kitenge, Paul Musa Obadia, Daniel Kyanika Wa Mukoma, Jean-Marie Lunda Ilunga, Tim S. Nawrot, Oscar Luboya Numbi, Erik Smolders & Benoit Nemery (2018) “Sustainability of artisanal mining of cobalt in DR Congo” Nature Sustainability volume 1, pages 495–504 doi: 10.1038/s41893-018-0139-4



Nissan batteries from AESC use manganese and nickel, no cobalt.
If you thermally manage them they retain range.

Thomas Pedersen

The added cost of an electrical car to ensure acceptable working conditions in the cobalt mines are probably less than a dollar and certainly ten dollars.

End users of Cobalt, i.e. the battery and car manufacturers cannot turn the blind eye; they have a moral responsibility to pursue this issue, once they become aware about it. Private consumers cannot take care of this, since they cannot, and should not be required to, ask questions about the chemistry of their battery and its origins.

Big buyers have the purchasing power to instigate changes.

There is nothing wrong with cobalt, or any other substance, as long as it is produced and used in a responsible manner.

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