2025-10-20T06:00:01Z

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Imagine biting into your favorite food, only to find out it’s laced with a potent neurotoxin. Shocking new research reveals that mercury pollution from artisanal and small-scale gold mining (ASGM) is tainting our crops—not from the soil, but directly from the air. Driven by skyrocketing gold prices that have surged over tenfold since 2000, unregulated mining is rapidly expanding, raising urgent alarms about our food security, our health, and environmental justice.

In a groundbreaking study published in the journal Biogeosciences, an international team of scientists led by Excellent O. Eboigbe, David McLagan from Queens University, and Abiodun Odukoya Mary from the University of Lagos, focused on a farming community in Nigeria, perilously close to an ASGM site. They discovered that crops grown just 500 meters from the mine showed mercury concentrations 10 to 50 times higher than those from fields located 8 kilometers away.

For years, experts believed that mercury contaminates crops primarily through the soil, leaching into water supplies before reaching plants. However, this new research flips that assumption on its head. Employing advanced mercury stable isotope analyses, the team revealed a startling truth: the majority of mercury in plants is coming from the atmosphere, absorbed through leaves during photosynthesis. David McLagan explains, “Mercury uptake by plants from air represents the largest sink of mercury from air to terrestrial systems.” While this phenomenon may help reduce global mercury levels, it poses significant health risks when it’s our staple crops that are absorbing this toxic element.

The leafy parts of the plants, which are often consumed by humans and livestock, retained the highest mercury concentrations. Even edible parts like cassava roots and maize kernels showed contamination, albeit at lower levels. While these levels may fall below international safety thresholds, experts caution that eating crops from ASGM-adjacent areas could still pose health risks. Current international standards are based on conservative consumption rates, and more severe contamination has been documented elsewhere.

Mercury, a powerful neurotoxin, poses grave long-term health risks, from cognitive impairments in children to severe cardiovascular and reproductive issues. Abiodun Mary points out the grim reality: “Miners will not stop using mercury for gold extraction unless they get a readily available alternative that is also cost-effective.”

According to the UN Environment Programme, ASGM is now the leading source of mercury emissions globally, yet regulation remains scarce, particularly in impoverished regions where such mining activities provide vital economic support. This study underscores an insidious consequence of the ASGM boom—food systems contaminated by hazardous mercury in the air, posing a hidden threat to communities.

The findings serve as a wake-up call for governments and organizations responsible for the enforcement of the Minamata Convention on Mercury. Current monitoring focuses primarily on water bodies and seafood, neglecting crops. As Abiodun Mary notes, “This work demonstrates that there are other dietary sources of mercury, and these different sources can have cumulative effects.”

As the study urges, immediate policies are needed to monitor and mitigate airborne mercury exposure in agricultural areas near mining sites. With the explosive growth of ASGM, millions of people across Africa, South America, and Asia could be jeopardizing their health by consuming locally grown food.