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Identifying human health risks from precious metal mining in Sierra Leone

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Water pollution results in more than two million human deaths every year, with a disproportionate amount of mortality occurring in developing countries. Tracing how and where water-borne pollutants enter the human body during everyday practices, and estimating the potential risks of these interactions, is critical to effective mitigation or adaptive practices to reduce health impacts. To understand these local processes, we worked with human communities along the Pampana River in Sierra Leone, Africa, from its headwaters at Lake Sonfon in the northeast—an area with both active and abandoned gold mining sites—to its confluence with the Jong River in the center of the country. We first measured the concentrations of heavy metals in fish that people eat and in riverbank soils where people congregate. We then estimated the risk people face, distinguishing carcinogenic risks from non-carcinogenic risks, as well as quantifying the risk to different age groups (i.e., adults vs children) at varying distances from the mining areas and operations, and in different seasons (wet vs dry season). We found dangerously high levels of heavy metals in fish and soil and conclude through life practice analysis that people living along the Pampana River face significantly elevated health risks in their everyday lives due to contamination from metals. The mean adult cancer risk was 1.01 × 10−3, while the mean child cancer risk was 9.42 × 10−3. Higher risks are associated with the wet season and living either downstream or closest to the mining operations and were particularly acute for children. Mining operations that directly impact riverine human settlements represent an area of concern for developing countries such as Sierra Leone.

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Data availability

All replication data can be accessed from our Harvard Dataverse repository (Marcantonio 2020).

Change history

  • 19 January 2021

    Springer Nature’s version of this paper was updated to present the missing editorial responsibility article note.


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The authors thank the Conservation Society of Sierra Leone for their efforts and partnership in the production of this research, and the Center for Environmental Science and Technology and the Stream and Wetland Ecology Laboratory at the University of Notre Dame for laboratory and analytical support. Special thanks are owed to Mike Brueseke, Jon Loftus, Whitney Conard, Sarah Klepinger, Sheku Kamara, Martin Bamin, Mark Golitko, and Cat Bolten for their assistance with various aspects of this study. Finally, the authors thank Bettina Genthe and Evan Dethier for their insightful and helpful reviews of this article.


RAM received funding from the GLOBES Graduate Program on Environment and Society at the University of Notre Dame in support of this research.

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Correspondence to Richard A. Marcantonio.

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All human subject research included in this study was conducted in accordance with our University of Notre Dame IRB approved protocol # 17-03-3691.

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Marcantonio, R.A., Field, S.P., Sesay, P.B. et al. Identifying human health risks from precious metal mining in Sierra Leone. Reg Environ Change 21, 2 (2021).

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  • Water pollution
  • Health risks
  • Environmental risk
  • Exposure assessment
  • Mining
  • Sierra Leone