A recent study published in Science presents new evidence on the significant impact of metal mining pollution on rivers and floodplains. It estimates that about 23 million people worldwide may be affected by potentially hazardous concentrations of toxic waste.
The study, led by Professors Mark Macklin and Chris Thomas from the University of Lincoln in the United Kingdom, offers a global perspective on environmental issues and health risks linked to metal mining activities.
The researchers built a new global georeferenced database covering 185,000 metal mines. They combined process-based modeling with empirical testing to gauge the global scale of mining pollution in river systems and its effects on human communities and livestock.
Using a model that accounts for all known active and inactive mining sites, the study examined pollutants such as lead, zinc, copper, and arsenic that are transported downstream from mining facilities, including tailings ponds used to store mining waste. These contaminants can settle along river channels and floodplains for extended periods.
23 million people affected
Published at a time of rising demand for metals to support the transition to green energy, the new findings reveal a pollution footprint spanning roughly 479,200 kilometers of river channels and 164,000 square kilometers of floodplains worldwide.
According to the results, approximately 23.48 million people reside in affected floodplains. The study also indicates support for 5.72 million cattle and more than 65,000 square kilometers of irrigated land. Given data gaps for some regions, the authors caution that these figures are conservative estimates.
People may encounter metal contaminants through multiple routes, including direct skin contact, accidental ingestion, inhalation of contaminated dust, and consumption of contaminated food and water grown in polluted soils.
This poses added risks to health in urban and rural communities in lower-income countries and in areas that rely on these rivers and floodplains, especially where water-related diseases are already prevalent.
In Western Europe, the United Kingdom, and the United States, pollution linked to mining presents a serious problem. It threatens water and food security and can undermine vital ecosystem services while contributing to antimicrobial resistance in the environment.
A rapid expansion of global metal mining is seen as essential for the world’s green energy transition, noted by the study’s coauthor, Professor Chris Thomas.
A call to action
Researchers describe a new method for estimating how mining waste disperses into river systems around the world. This approach offers governments, regulators, the mining industry, and local communities a practical tool to assess waste impacts on-site and downstream.
They emphasize that basin-scale mining significantly affects ecosystems and human health. The authors hope the method will help reduce environmental impacts from both historic and current mining and, crucially, minimize risks from future mining projects while safeguarding food and water security.
Professor Deanna Kemp of the Sustainable Minerals Institute at the University of Queensland, who contributed to the project, called the results sobering. She noted that mining can cause considerable downstream damage over long periods and stressed the need to balance benefits with stronger safeguards for people living and working in affected zones.
Reference work: Science journal, with attribution to the authors and the publishing journal.
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