Sustainability of artisanal mining of cobalt in DR Congo


The sustainability of cobalt is an important emerging issue because this critical base metal is an essential component of lithium-ion batteries for electric vehicles. More than half of the world’s cobalt mine production comes from the Katanga Copperbelt in DR Congo, with a substantial proportion (estimated at 15–20%) being extracted by artisanal miners. Here we show, in a case study performed in the town of Kolwezi, that people living in a neighbourhood that had been transformed into an artisanal cobalt mine had much higher levels of cobalt in their urine and blood than people living in a nearby control area. The differences were most pronounced for children, in whom we also found evidence of exposure-related oxidative DNA damage. It was already known that industrial mining and processing of metals has led to severe environmental pollution in the region. 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.

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Fig. 1: Satellite images of Kolwezi and the study area.
Fig. 2: Concentrations of trace elements in surface dust and ore.
Fig. 3: Concentrations of cobalt, uranium and manganese in urine and blood.
Fig. 4: Relation between concentrations of cobalt and 8OHdG in urine.

Data availability

The (fully anonymized) data that support the findings of this study are available from the corresponding author upon reasonable request.


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We thank C. Cime Jinga, former mayor of Kolwezi, other local authorities, A. Makula and other local collaborators for their support and assistance during the surveys, and J. Van Damme for his help and support. We thank G. Deumer, W. Claassen and K. Coorevits for measuring trace elements by ICP-MS. The costs of metal analyses were covered by a VLIR-UOS grant (ZRDC2015PR090 to E.S., C.B.L.N. and B.N.) and by IDEWE (External Service for Prevention and Protection at Work, Heverlee, Belgium). The costs of the 8OHdG measurements were covered by a European Research Council grant to T.S.N. (ERC-2012-StG 310898). B.N. analysed the data and wrote the manuscript during a sabbatical leave (supported by grant K8.004.16N from FWO-Vlaanderen) at the Centre for Research in Environmental Epidemiology (CREAL), now Barcelona Institute for Global Health (ISGlobal).

Author information




C.B.L.N. and B.N. conceived the study, did the fieldwork, collected the samples and wrote the manuscript. T.K.-K., P.M.O. and D.K.W.M. assisted with the processing of samples. L.C. performed the statistical analyses. V.H. was responsible for the analyses of metals in human samples. E.S. was responsible for the analyses of metals in environmental samples. N.D.S. performed the measurements of 8OHdG under the supervision of T.S.N. T.D.P. gave advice on geology and policy issues. J.-M.L.I. gave advice on geology. O.L.N. gave advice on child health. All authors gave input to successive drafts of the manuscript and approved its final version. C.B.L.N. and B.N. had full access to all the data.

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Correspondence to Benoit Nemery.

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Banza Lubaba Nkulu, C., Casas, L., Haufroid, V. et al. Sustainability of artisanal mining of cobalt in DR Congo. Nat Sustain 1, 495–504 (2018).

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