A group of researchers has developed a two-pronged approach to detoxifying artisanal gold mining, with the goal of helping miners maintain their livelihoods while reducing associated health risks.
Knowing that approaches focused on removing mercury had not worked in the past, a team from Michigan State University, Colorado State University, the Peace Corps and Duke University began talking to miners in Senegal to identify ways to reduce emissions that would be sustainable. The team used what they learned to develop a new way of doing things.
The first pillar of the approach was an education programme delivered by local community members about the dangers of mercury, the symptoms of exposure and how miners could protect themselves.
The trainers also provided information on the second pillar – equipment known as retorts.
Retorts are metal enclosures that allow miners to burn the mercury off the gold without releasing fumes into the atmosphere. Instead, the fumes are collected and exhausted into a bucket of water, where the mercury condenses and can be recovered.
Local metalworkers built the retorts for the study, using readily available materials and a design provided by the research team, which included tweaks from the miners.
The team worked with nine mining communities to measure the impact of these interventions. Three of the communities received both education and retorts, three received education only, and three provided a control group that received neither education nor retorts.
This allowed the team to show conclusively that providing education and retorts worked. The miners were more aware of the dangers of mercury and how to limit their exposure. They used mercury less and, when they did, they used retorts more.
“These effects trickled down to the control villages,” said lead researcher Jacqueline ‘Jackie’ Gerson in a media statement. “There was this kind of social spillover where people shared the education and the responses.”
Based on the project’s success in Senegal, Gerson believes the approach could be extended to mining operations in other countries to further reduce emissions. But she stresses that it has to be the whole approach, not just the solutions found in Senegal.
“Miners need to be involved from the beginning to find specific solutions that work in their unique physical and social environments,” Gerson said.
In her view, artisanal mining in Senegal is different from artisanal mining in Peru, so the specific techniques that worked in one place may not work in the other. However, the approach of working with miners and their neighbours to find trustworthy solutions will be transferable.
“We have to work with the people who live and work in these places if we’re going to be successful,” says Gerson.
Where do the mercury emissions go?
Gerson, who works at Michigan State University, along with Heidi Hausermann of Colorado State University and Richard Amankwah, vice chancellor of the University of Mines and Technology in Ghana, recently received a grant to answer big, looming questions about where mercury emissions from artisanal and small-scale gold mining (ASGM) go, and how and whether these mercury emissions can enter the food web through crops.
This knowledge could help inform policies and practices to better protect miners, their neighbours and nearby communities.
“Locally and regionally, we don’t know where a lot of this mercury goes once it’s emitted,” Gerson said. “The question is whether plants take it up in their leaves or through their roots, and it may be that they don’t. That would be great. We hope so, but we don’t know.
To date, most research on mercury emissions has focused on what happens to mercury in aquatic environments, which makes sense because microbes living in oxygen-deprived ecosystems – such as underwater – are very efficient at converting mercury into a compound called methylmercury, which is the form of mercury that causes neurotoxic effects.
In aquatic environments, methylmercury then gets to the bottom of the food chain. The chemical accumulates in larger fish and marine life that prey on smaller organisms, which is why certain seafood poses mercury concerns for humans.
However, because of the abundance of oxygen above water, there has been little research into the fate of methylmercury on land.
“We know that the terrestrial conversion of mercury to methylmercury is less efficient, but there’s a lot of mercury getting into terrestrial ecosystems around artisanal gold mining,” Gerson said. “So it is a concern.”
This concern is underscored by the fact that during previous work in Peru, Gerson observed evidence that songbirds in forests near ASGM activity were exposed to mercury, likely through their diet of fruit and bugs.
Now, with the grant, Gerson and her team will track how mercury moves through terrestrial environments and where it ends up, to paint a much fuller picture of its impact on public health.
