Phytoremediation and Phytoextraction in Sub-Saharan Africa: A Dual Solution for Remediation and Revenue

What was reviewed?

This review paper evaluates the potential of phytoremediation and phytoextraction as cost-effective strategies to address heavy metal pollution caused by mining activities in Sub-Saharan Africa, a region suffering from widespread environmental degradation and inadequate governance. The authors present a conceptual approach that combines phytoremediation with economic valorization through phyto-mining, proposing the sale of extracted metals to fund remediation efforts and support local economies. The paper emphasizes the viability of hyperaccumulator plants in cleaning up heavy metal-contaminated soils while yielding saleable metals, especially cobalt and copper. It outlines the social and financial barriers hindering implementation. This review explores phytoremediation and phytoextraction as cost-effective solutions for mining pollution in Sub-Saharan Africa, highlighting hyperaccumulator plants that can remediate heavy metal-contaminated land and generate income through metal recovery, with implications for heavy metal testing and certification, remediation, and ethical sourcing.

Who was reviewed?

The review focuses on communities across Sub-Saharan Africa, particularly those impacted by industrial and artisanal mining in regions like the Zambian and Katanga Copperbelts. It highlights the lack of environmental governance in countries such as Zambia, the Democratic Republic of Congo (DRC), and Zimbabwe. These areas suffer from extreme environmental degradation, health risks associated with heavy metal exposure, and food insecurity due to contamination of staple crops like cassava and sweet potatoes. Hyperaccumulator species such as Haumaniastrum robertii and Aeolanthus biformifolius from the Central African Copperbelt are discussed as local solutions to these region-specific challenges.

Most important findings

The review identifies several core insights highly relevant to heavy metal testing, certification, and manufacturing reform. Heavy metal contamination from mining—including cobalt, lead, cadmium, nickel, and copper—is widespread and persistent across Sub-Saharan Africa, posing serious environmental and public health risks. The situation is further compounded by weak governance scores across many countries in the region, as shown in Table 1 (page 4), which limit the enforcement of environmental safeguards and the implementation of remediation strategies.

In response, the authors highlight phytoremediation and phytoextraction as scalable, low-cost solutions, particularly suited to regions with limited infrastructure and funding. These techniques utilize native hyperaccumulator plants such as Haumaniastrum robertii and Aeolanthus biformifolius, which are capable of accumulating up to 1 wt% of cobalt and copper, respectively, making substantial recovery of metals from contaminated soils feasible, as demonstrated in Table 2 (page 5). Even after phytoextraction becomes economically unviable, phytoremediation can continue to deliver value through the production of biofuels, bioenergy, or biomass-derived fertilizers. When supported by economic incentives and community engagement, this approach can transform toxic, post-mining landscapes into food-grade agricultural land, creating long-term environmental and economic benefits.

Revenue Potential of Phytomining (adapted from Table 2, page 5)

Key implications

The review ultimately calls for the urgent integration of phytoremediation into both policy and practice, emphasizing the use of certification, traceability, and value recovery as key mechanisms to overcome socioeconomic barriers.  It advocates a shift from reliance on weak governance structures toward self-sustaining, community-driven remediation strategies rooted in nature-based solutions. This has significant implications for environmental safety certification, heavy metal testing, and the development of sustainable remediation practices. Certification programs operating in contaminated regions could recognize phytoremediation as an eligible remediation method, provided the extracted metals meet established safety thresholds. Phytomining presents an economic pathway to fund remediation efforts without external financing, offering an appealing model for public-private partnerships and development initiatives.

For manufacturers—particularly in the tech and automotive sectors that depend on cobalt from Sub-Saharan Africa—the inclusion of certified, phytomined metals into supply chains could strengthen ethical sourcing commitments. Additionally, a Heavy Metal Tested and Certified label could be broadened to include land or biomass products that have undergone validated phytoremediation. To ensure successful implementation, the review highlights the importance of educational outreach, robust economic feasibility assessments, and technical training—areas where certification bodies can play a pivotal role by supporting capacity-building programs.

Citation

Lee J, Kaunda RB, Sinkala T, Workman CF, Bazilian MD, Clough G. Phytoremediation and phytoextraction in Sub-Saharan Africa: Addressing economic and social challenges.Ecotoxicol Environ Saf. 2021;226:112864. doi:10.1016/j.ecoenv.2021.112864

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References

1. https://doi.org/10.1177/0004563217706381. Davies M, Sarri G, Lumsden MA.. (Ann Clin Biochem. 2017;54(5):516-518.)