The quickest way to separate gold from rock, Sadio Camara says, is with a drop of mercury. She empties a dime-sized packet of the silvery liquid into a plastic bucket of muddy sediment outside her home in southeastern Senegal. With bare hands and no mask, she swirls the mixture as her children look on.

“I know mercury isn’t good for your health — that’s why I don’t drink the water it comes into contact with,” she said. “I only process small amounts of gold, so there’s no danger.”

But even small-scale exposure can carry serious risks.

Across West Africa, mercury — a potent neurotoxin — remains the dominant method for extracting gold from ore in the region’s booming informal mining sector, much of it illegal and unregulated. In Senegal’s gold-rich Kedougou region, women like Camara use the metal regularly, often without protective gloves and masks, to make a living.

Mercury exposure can cause irreversible brain damage, developmental delays, tremors and loss of vision, hearing and coordination. Once released, it spreads easily through air, water and soil. Particularly after heavy rains, it contaminates rivers, poisons fish and accumulates up the food chain.

A 2018 Duke University-led study found mercury levels in soils, sediments and water near artisanal gold mining villages in southeastern Senegal that exceeded safety thresholds set by the World Health Organization and U.S. Environmental Protection Agency by 10 to 100 times.

In artisanal mining, mercury is prized for its ability to bind quickly and easily to gold. Miners mix the liquid metal into crushed ore, and the mixture is then heated — often over open flames — to evaporate the mercury and leave behind a lump of gold. The process is cheap, effective and dangerous.

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“If it hurt right away, like a knife, people would stop. But the issue is that it takes years for the dangers to manifest,” said Doudou Dramé, president of the Observatoire Territoriale du Secteur Extractif, an organization that advocates for safer conditions for gold miners in Kedougou. “People are dumping it directly into the river. They’re burning it in the open, releasing toxic smoke into the air. It’s extremely dangerous.”

Artisanal and small-scale gold mining is the largest global source of mercury emissions, even more than the burning of coal, according to the UN Environment Programme. In Senegal alone, artisanal mines are estimated to release between 12 and 16 metric tons of mercury each year.

“Kedougou has rich land — very rich land,” Dramé said. “Now mercury is everywhere. Our animals consume it, and it comes back to us. Even the soil is no longer fertile.”

For women, a life that puts them in mercury's way

Along the muddy banks of a rust-colored pond, dozens of women wade knee-deep as they rinse piles of sediment in search of gold. Children dart between mounds of earth while the runoff pools around their feet. With little access to clean water, many women spend long hours in local waterways to work, bathe their children, wash clothes and clean dishes.

“Women are much more exposed than men,” said Modou Goumbala, the monitoring and evaluation manager at La Lumiere, an NGO that supports community development in southeastern Senegal.

That exposure can be especially dangerous for pregnant and nursing women. Mercury can cross the placenta, putting fetuses at risk of developmental delays and birth defects. Infants may also absorb the toxin through contaminated breast milk.

Inside her kitchen hut not far from the stream, Camara heats a nugget of mercury-laced sediment with a metal spoon over an open flame. The toxic metal evaporates and leaves behind a kernel of gold. There’s no mask, no gloves — just the raw materials and her bare hands. Her children stand just a few feet away, watching and breathing the fumes.

Camara said she doesn’t usually handle the burning herself; that task is typically left to men. But she and other women regularly mix and shape the mercury amalgam with no protection. One of her children suffers from frequent stomachaches, though she hasn’t noticed any other symptoms. Still, the risks loom.

Why take the risks? Because gold pays

“The easiest way to earn money today is gold mining,” Camara said. “Subsistence agriculture will not provide you enough for food or other needs.”

In Senegal, gold processors like Camara typically process between 5 and 10 grams of gold per month, earning the equivalent of $370 to $745 — more than double the national average salary of about $200.

Senegal ratified the Minamata Convention on Mercury in 2016, pledging to reduce mercury use and pollution. But the substance remains widely accessible. Most of the country’s supply comes from Guinea, Mali, Burkina Faso and Ghana, with smaller amounts smuggled from dental clinics in Dakar, according to a 2022 report by the Institute for Security Studies.

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In 2020, the government promised to build 400 mercury-free gold processing units. So far, only one has been constructed — in Bantaco, about 15 miles from Camara’s home. The facility uses gravity to separate gold from ore, eliminating the need for mercury by relying on sluices and shaking tables.

During a recent visit, the rusting slab of metal sat unused beneath a corrugated roof.

“People used it for a while, but then they stopped, because one single unit can’t cover an entire community,” Goumbala said. “Naturally, those who were nearby could use it. But for those who are very far away, they can’t afford to transport the ore all the way, process it and then go back. It’s extra work. That’s a problem.”

Camara said she tried the unit, but in addition to being far away, it was less effective at isolating gold – some was lost in the process.

Repeated efforts to schedule an interview with Senegal’s director of artisanal and small-scale mining were unsuccessful. The director later said the department had been suspended. He did not provide a reason.

Senegal swore in a new president in 2024, but residents say the problems remain.

“There’s a new administration in place, but promises are still just promises,” Goumbala said. He believes the lack of progress is due to limited funding.

In an effort to curb pollution, authorities temporarily suspended mining within 500 meters (1,640 feet)of the Faleme River, which cuts through Senegal’s gold belt and forms part of the border with Mali.

But enforcement is weak as officials struggle to stem the influx of informal miners, many of whom arrive from neighboring countries. Critics say the measure barely scratches the surface of the problem.

“The solution is to install the gold processing units within the communities — at least one per village,” Goumbala said.

Even so, he acknowledged the challenges: The machines are expensive, difficult to maintain and require replacement parts that are only available abroad.

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There’s also resistance among miners, who say mercury is more efficient and profitable.

“We need to convince communities that even if they make more money using mercury, in the end, they’ll spend that profit on treating illnesses caused by it,” Goumbala said. “The long-term consequences are far worse.”