Scientists Examine Amazon Gold Mining’s Role in Birth Disabilities

Brazilian scientists are conducting a landmark study to determine whether Amazon gold mining mercury contamination causes severe neurological disorders and disabilities in Indigenous children. Early findings from the research, carried out by the public health institute Fiocruz, suggest widespread mercury exposure among communities living along contaminated rivers in Pará state, where the 2025 United Nations climate summit (COP30) will be held.

Researchers have identified at least 36 Indigenous people, mostly children, showing neurological conditions that cannot be explained by genetics. These findings may soon establish the first direct scientific link between mercury exposure and disabilities in Indigenous populations of the Amazon.

“We are collecting evidence that connects mercury contamination to neurological disorders in children,” said Paulo Basta, a Fiocruz researcher who has studied mercury’s effects on Indigenous communities for more than 30 years.

Researchers find alarming mercury levels

Mercury, used by illegal miners to separate gold from sediment, seeps into river systems and accumulates in fish that are a major food source for local communities. Tests conducted by Fiocruz scientists revealed that mothers in Munduruku villages had mercury levels averaging five times higher than Brazil’s safety limits, while their babies’ levels were three times higher.

In Sai Cinza, a Munduruku village surrounded by illegal mining sites, families such as that of three-year-old Rany Ketlen have seen children suffer from muscle spasms, swallowing difficulties, and delayed development. Researchers are tracking 176 pregnant women in the area and monitoring their children through the first years of life.

“The contamination cycle continues through food, breast milk, and even the placenta,” Basta said. “Even if mining stops today, Amazon gold mining mercury will remain in the environment for decades.”

Indigenous families face tough choices

Despite government warnings, Indigenous families say avoiding river fish is nearly impossible. “If we obey their rules, we will go hungry,” said Chief Zildomar Munduruku, a community nurse in Sai Cinza.

Many residents work in mining themselves, driven by poverty and lack of alternative livelihoods. Rosielton Saw, who mines near his village, said the income from gold provides his family’s basic needs. “We know Amazon gold mining mercury is dangerous, but without mining, there’s nothing to eat,” he said.

Government health agencies have documented dozens of cases of neurological illness in the wider region. However, limited access to testing and medical care has made it difficult to confirm the extent of mercury poisoning.

Long-term impact likely to persist

Brazil’s Health Ministry said it has increased monitoring of mercury in the Munduruku Territory, trained health workers to detect early symptoms of poisoning, and funded clean water projects for isolated communities. Still, experts warn the problem is far from contained.

Even after thousands of illegal miners were expelled from Indigenous lands under President Luiz Inácio Lula da Silva’s administration, the mercury they left behind continues to circulate through the air, soil, and water.

Scientists caution that proving direct causation remains complex. Fiocruz geneticist Fernando Kok said many Indigenous communities also face other risk factors, such as infectious diseases and genetic conditions resulting from small population size. “It is likely mercury is one of the causes, but not the only one,” Kok said.

The study’s final results are expected by late 2026. Until then, communities continue to live with uncertainty — and contaminated rivers that sustain them.

“It’s a perfect crime because it leaves no signature,” Kok said. “The evidence fades, but the damage from Amazon gold mining mercury remains.”

Visit The Lifesciences Magazine to read more.