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International mercury regulations fail to protect the environment, public health: study

  • Mercury is one of the most concerning chemicals affecting public health and the environment. The chemical can enter local watersheds and poison flora and fauna, while leaving humans with memory loss, seizures, vomiting and lung damage, among other problems.
  • A recent study found that data collection for mercury use is so inconsistent that it can’t be relied on for understanding trends in artisanal and small-scale mining.
  • The UN Minamata Convention on Mercury, which went into effect in 2017, requires countries to collect data on mercury use but doesn’t say how that data should be collected, resulting in inconsistencies between countries.

Around 15 million people across the globe are working at artisanal and small-scale gold mining sites, nearly a third of them women and children. Instead of operating advanced equipment supplied by formal mining companies subject to government oversight, they use basic tools, bulldozers and unregulated chemicals.

In many cases, miners vaporize mercury to separate gold from the soil, a process known as amalgamation. While it can be faster than other methods, the process also leads to serious environmental and public health consequences. Mercury is known to lead to memory loss, seizures, vomiting and lung damage, among other problems.

The World Health Organization considers mercury to be one of the top-ten chemicals of public health concern. Yet regulations on its use are still relatively new. The UN Minamata Convention on Mercury only went into force in 2017, an attempt by the international community to collaborate on mitigating mercury use. Nearly 140 countries have signed onto the treaty, with the UN saying that 84% of them have submitted some update on improved mercury regulation policy.

But their efforts in artisanal and small-scale gold mining appear to be flawed, a March study in Environmental Science & Policy found. And the progress being made to limit mercury use in mining is either misrepresented or just too inconsistent to reach a conclusion about.

“We realized that there were a lot of differences with these mercury estimates and how they were developed,” said Michelle Schwartz, the study’s lead author and engineer at environmental consulting firm Tanaq Environmental. “But we also realized that there was a significant amount of uncertainty with the estimates. The big challenge with this uncertainty is how it was going to affect policymaking.”

Mercury poisons the water at a small-scale mining site in Camarines Norte, Philippines. (Photo courtesy of ILO Asia-Pacific)

Schwartz and other researchers analyzed the national action plans from 25 countries signed onto the Minamata Convention. One of the biggest issues with the plans was inconsistent and unreliable data gathering, Schwartz said. In order to estimate how much mercury is being used, countries conduct workshops, visit mine sites or interview key stakeholders like gold and jewelry buyers. There’s nothing in the Minamata Convention that states which approach is best or even, for example, how many mine site visits or interviews need to be conducted to create an accurate estimate.

Some countries relied on “emission factors” rather than on collecting hard data, a mathematical formula that assumes a certain amount of mercury is being used per mine site.

Not only is all of this data potentially incomplete, the study said, but it’s also too inconsistent to compare country to country, making it nearly impossible to know which policies are working and where.

“If countries don’t understand what the biggest contributors to mercury emissions are, how are they supposed to put a plan together in order to attack that?,” co-author Kathleen Smits, a professor of global development at Southern Methodist University, said. “It’s a little too much window dressing and not data-driven enough to be able to actually make a measurable impact.”

There also isn’t a penalty for countries who turn in data collected with methods that aren’t sufficiently rigorous. Instead, the Minamata Convention only lays out possible approaches to data collection.

“There’s no teeth to what it’s suggesting,” Smits said.

Workers in Madagascar look up from a small-scale gold mining site. (Photo courtesy of Global Environment Facility)

At the same time, the convention is intentionally designed that way so countries can do what works for them without being alienated from participating. The UN Environment Program, which oversees the Minamata Convention, didn’t respond to a request for comment for this story.

Indigenous groups in Brazil and Venezuela can no longer drink the water they could twenty years ago due to mercury pollution, Mongabay previously reported. And around 70% of miners in Cameroon have shown signs of mercury poisoning, including high levels of the chemical in tests on their hair.

Miners tend to recognize that inhaling fumes from vaporized mercury can be dangerous for their health and the environment. But they often ignore the longer-term effects that mercury can have when it enters the local ecosystem, climbing up the food chain through fish and other animals consumed by humans.

Miners also continue to use mercury because it’s the only way they’ve been trained, researchers said. There’s also a misconception that using other, cleaner extraction methods won’t produce the yields that mercury does. At the same time, residents who have been working in the area for decades can help policymakers develop solutions that work for everyone, such as safely using cyanide instead of mercury.

“Local engagement is going to be a huge factor,” Schwartz said. “It’s probably going to be the best way to approach it because every community is different.”

Banner image: Illegal gold mining sites in Peru. Photo courtesy of Peru’s Ministry of Defense.


Schwartz, M., Smits, K., & Phelan, T. (2023). Quantifying Mercury use in artisanal and small-scale gold mining for the Minamata Convention on Mercury’s National Action Plans: Approaches and Policy Implications. Environmental Science & Policy, 141, 1–10.

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