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.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

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.


  1. 1.

    Harper, E. M., Kavlak, G. & Graedel, T. E. Tracking the metal of the goblins: cobalt’s cycle of use. Environ. Sci. Technol. 46, 1079–1086 (2012).

  2. 2.

    Cobalt uses. Cobalt Institute (2017).

  3. 3.

    Shedd, K. B., Mccullough, E. A. & Bleiwas, D. I. Global trends affecting the supply. Min. Eng. 69, 37–42 (2017).

  4. 4.

    Nelson, E. Digging for blue: electric cars have made this once obscure metal the hottest commodity of 2017. Quartz (18 December 2017).

  5. 5.

    Schmidt, T., Buchert, M. & Schebek, L. Investigation of the primary production routes of nickel and cobalt products used for Li-ion batteries. Resour. Conserv. Recycl. 112, 107–122 (2016).

  6. 6.

    Olivetti, E. A., Ceder, G., Gaustad, G. G. & Fu, X. Lithium-ion battery supply chain considerations: analysis of potential bottlenecks in critical metals. Joule 1, 229–243 (2017).

  7. 7.

    Critical raw materials. European Commission (2017).

  8. 8.

    Final List of Critical Minerals 23295–23296 (Federal Register, 2018);

  9. 9.

    Wilburn, D. R. Cobalt Mineral Exploration and Supply from 1995 Through 2013 Scientific Investigations Report 2011–5084 (US Geological Survey, 2012).

  10. 10.

    World Development Indicators: Congo, Dem. Rep. (World Bank, accessed 22 February 2018);

  11. 11.

    Worldwide Governance Indicators (World Bank, accessed 22 February 2018);

  12. 12.

    Hsu, A. et al. 2016 Environmental Performance Index (Yale Univ., New Haven, CT, 2016);

  13. 13.

    Milesi, J. P. et al. An overview of the geology and major ore deposits of Central Africa: explanatory note for the 1:4,000,000 map ‘Geology and major ore deposits of Central Africa’. J. African Earth Sci. 44, 571–595 (2006).

  14. 14.

    Banza, C. L. N. et al. High human exposure to cobalt and other metals in Katanga, a mining area of the Democratic Republic of Congo. Environ. Res. 109, 745–752 (2009).

  15. 15.

    De Putter, T., Decrée, S., Nkulu, C. B. L. & Nemery, B. Mining the Katanga (DRC) Copperbelt: geological aspects and impacts on public health and the environment — towards a holistic approach. In IGCP/SIDA Project 594, Inaugural Workshop, Kitwe, Zambia (ed. Kribek, B.) 14–17 (Czech Geological Survey, 2011);

  16. 16.

    Cuvelier, J. Work and masculinity in Katanga’s artisanal mines. Afr. Spectr. 49, 3–26 (2014).

  17. 17.

    Elenge, M. M. & De Brouwer, C. Identification of hazards in the workplaces of artisanal mining in Katanga. Int. J. Occup. Med. Environ. Health 24, 57–66 (2011).

  18. 18.

    “This is What We Die For.” Human Rights Abuses in the Democratic Republic of the Congo Power the Global Trade in Cobalt (Amnesty International, 2016);

  19. 19.

    Tsurukawa, N., Prakash, S. & Manhart, A. Social Impacts of Artisanal Cobalt Mining in Katanga, Democratic Republic of Congo (Öko-Institut, 2011);

  20. 20.

    Cobalt from the DRC — Potential, Risks and Significance for the Global Cobalt Market v. 53 (Commodity Top News, BGR, 2017);

  21. 21.

    Frankel, T. C. The cobalt pipeline: tracing the path from deadly hand-dug mines in Congo to consumers’ phones and laptops. The Washington Post (30 September 2016);

  22. 22.

    Soil, Ground Water and Sediment Standards for Use under Part XV.1 of the Environmental Protection Act PIBS#7382e01 (Canadian Ministry of the Environment, 2011);

  23. 23.

    Guidelines for Drinking-water Quality 4th edn (World Health Organization, 2011);

  24. 24.

    Gibb, H. & O’Leary, K. G. Mercury exposure and health impacts among individuals in the artisanal and small-scale gold mining community: a comprehensive review. Environ. Health Perspect. 122, 667–672 (2014).

  25. 25.

    Dooyema, C. A. et al. Outbreak of fatal childhood lead poisoning related to artisanal gold mining in northwestern Nigeria, 2010. Environ. Health Perspect. 120, 601–607 (2012).

  26. 26.

    2015 TLVs and BEIs. Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices (American Conference of Governmental Industrial Hygienists, 2015).

  27. 27.

    Lison, D. in Handbook on the Toxicology of Metals 4th edn, Vol. II (eds. Nordberg, G. F., Fowler, B. A. & Nordberg, M.) 743–763 (Academic Press, Elsevier, 2015).

  28. 28.

    Lison, D., Buchet, J. P., Swennen, B., Molders, J. & Lauwerys, R. Biological monitoring of workers exposed to cobalt metal, salt, oxides, and hard metal dust. Occup. Environ. Med. 51, 447–450 (1994).

  29. 29.

    Fourth National Report on Human Exposure to Environmental Chemicals, 2009: Updated tables, February 2015 (Centers for Disease Control and Prevention, 2015).

  30. 30.

    Hoet, P., Jacquerye, C., Deumer, G., Lison, D. & Haufroid, V. Reference values and upper reference limits for 26 trace elements in the urine of adults living in Belgium. Clin. Chem. Lab. Med. 51, 839–849 (2013).

  31. 31.

    Nisse, C. et al. Blood and urinary levels of metals and metalloids in the general adult population of Northern France: the IMEPOGE study, 2008–2010. Int. J. Hyg. Environ. Health 220, 341–363 (2017).

  32. 32.

    Mees, F. et al. Concentrations and forms of heavy metals around two ore processing sites in Katanga, Democratic Republic of Congo. J. Afr. Earth Sci. 77, 22–30 (2013).

  33. 33.

    André, G. & Godin, M. Child labour, agency and family dynamics: the case of mining in Katanga (DRC). Childhood. 21, 161–174 (2014).

  34. 34.

    Landrigan, P. J., Kimmel, C. A., Correa, A. & Eskenazi, B. Children’s health and the environment: public health issues and challenges for risk assessment. Environ. Health Perspect. 112, 257–265 (2004).

  35. 35.

    Cheyns, K. et al. Pathways of human exposure to cobalt in Katanga, a mining area of the D.R. Congo. Sci. Total Environ. 490, 313–321 (2014).

  36. 36.

    US EPA Exposure Factors Handbook 2011 Edition (Final Report) (US Environmental Protection Agency, Washington DC, 2011).

  37. 37.

    Orloff, K. G. et al. Human exposure to uranium in groundwater. Environ. Res. 94, 319–326 (2004).

  38. 38.

    Hao, Z. et al. Levels of rare earth elements, heavy metals and uranium in a population living in Baiyun Obo, Inner Mongolia, China: a pilot study. Chemosphere 128, 161–170 (2015).

  39. 39.

    Lourenço, J. et al. Biomonitoring a human population inhabiting nearby a deactivated uranium mine. Toxicology 305, 89–98 (2013).

  40. 40.

    Baker, M. G. et al. Blood manganese as an exposure biomarker: state of the evidence. J. Occup. Environ. Hyg. 11, 210–217 (2014).

  41. 41.

    Loft, S., Fischer-Nielsen, A., Jeding, I. B., Vistisen, K. & Poulsen, H. E. 8-Hydroxydeoxyguanosine as a urinary biomarker of oxidative DNA damage. J. Toxicol. Environ. Health 40, 391–404 (1993).

  42. 42.

    Barregard, L. et al. Human and methodological sources of variability in the measurement of urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine. Antioxid. Redox. Signal. 18, 2377–2391 (2013).

  43. 43.

    Paustenbach, D. J., Tvermoes, B. E., Unice, K. M., Finley, B. L. & Kerger, B. D. A review of the health hazards posed by cobalt. Crit. Rev. Toxicol. 43, 316–362 (2013).

  44. 44.

    Grandjean, P. & Landrigan, P. J. Neurobehavioural effects of developmental toxicity. Lancet Neurol. 13, 330–338 (2014).

  45. 45.

    Dinocourt, C., Legrand, M., Dublineau, I. & Lestaevel, P. The neurotoxicology of uranium. Toxicology 337, 58–71 (2015).

  46. 46.

    Faber, B., Krause, B. & Sánchez De LaSierra, R. Artisanal Mining, Livelihoods, and Child Labor in the Cobalt Supply Chain of the Democratic Republic of Congo Policy Report (Center for Effective Global Action, 2017);

  47. 47.

    Squadrone, S. et al. Human exposure to metals due to consumption of fish from an artificial lake basin close to an active mining area in Katanga (D.R. Congo). Sci. Total Environ. 568, 679–684 (2016).

  48. 48.

    Bridge, G. Contested terrain: mining and the environment. Annu. Rev. Environ. Resour. 29, 205–259 (2004).

  49. 49.

    De Putter, T. & Decrée, S. Le potentiel minier de la République démocratique du Congo (RDC): mythes et composantes d’une dynamique minière. In Conjonctures Congolaises 2012: Politique, Secteur Minier et Gestion des Ressources Naturelles en RDC (eds. Marysse, S. & Omasombo, J.) 47–62 (MRAC, L’Harmattan, 2013).

  50. 50.

    Trefon, T. Congo’s Environmental Paradox — Potential and Predation in a Land of Plenty (Zed Books, London, 2016).

  51. 51.

    Geenen, S. A dangerous bet: the challenges of formalizing artisanal mining in the Democratic Republic of Congo. Resour. Policy 37, 322–330 (2012).

  52. 52.

    Hilson, G., Hilson, A., Maconachie, R., McQuilken, J. & Goumandakoye, H. Artisanal and small-scale mining (ASM) in sub-Saharan Africa: re-conceptualizing formalization and ‘illegal’ activity. Geoforum 83, 80–90 (2017).

  53. 53.

    De Putter, T. & Delvaux, C. Certifier les ressources minérales critiques dans la région des Grands lacs. Polit. Etrang. 78, 99–112 (2013).

  54. 54.

    Trefon, T. & De Putter, T. Ressources Naturelles et Développement: le Paradoxe Congolais (MRAC, L’Harmattan, Belgium, 2017).

  55. 55.

    Cocker, J., Mason, H. J., Warren, N. D. & Cotton, R. J. Creatinine adjustment of biological monitoring results. Occup. Med. 61, 349–353 (2011).

  56. 56.

    Sughis, M., Nawrot, T. S., Haufroid, V. & Nemery, B. Adverse health effects of child labor: high exposure to chromium and oxidative DNA damage in children manufacturing surgical instruments. Environ. Health Perspect. 120, 1469–1474 (2012).

Download references


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.

Correspondence to Benoit Nemery.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Supplementary Information

Supplementary Figures 1–2, Supplementary Tables 1–6

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Further reading