Riccardo Liguori Brazil fights illegal mineral extraction in the Amazon, but the legacy of mercury used by miners continues to threaten the health of local communities and the entire ecosystem
@Canva
The Brazilian Amazon has long been the scene of a devastating, hidden conflict: illegal gold mining. The key players in this gold rush are the garimpeiros, artisanal miners who often operate outside the law, disregarding regulations and environmental concerns.
Despite the efforts of the Brazilian government under President Lula, who has targeted these miners and their equipment, an invisible enemy continues to poison the land and its inhabitants: mercury.
The poison that doesn’t evaporate
This liquid metal, used by garimpeiros to separate gold from ore, is a silent killer. It seeps into rivers, contaminates fish, and accumulates in the food chain, reaching alarming levels in the bodies of indigenous populations who have lived in harmony with the forest for centuries.
A recent study by the Escolhas Institute, titled “Where Does All This Mercury Come From?”, sheds light on a disturbing aspect of this crisis. Between 2018 and 2022, at least 185 metric tons of mercury of unknown origin may have been used in Brazilian gold mines. This is alarming, especially considering that official mercury imports into the country dropped from 67 to 15 metric tons per year during the same period.
Larissa Rodrigues, a researcher at Escolhas and the study’s lead author, stated, “These data reveal a massive failure in official control over the trade of something that poses a serious danger to human health and environmental balance“.
Once in contact with water, mercury transforms into methylmercury, a toxic compound that can move up the food chain. It accumulates in high concentrations in carnivorous fish, which are a crucial food source for local communities.
Children: the most affected victims
Mercury has a particularly severe impact on the health of indigenous populations, whose food and water come directly from nature.
In Brazil, mining activities on indigenous lands are strictly prohibited, but this hasn’t stopped the spread of garimpos: the total area affected by illegal mining in the Brazilian Amazon has tripled in the last 20 years, much of it within indigenous territories.
One of the most affected indigenous communities in the Brazilian Amazon are the Yanomami, who live in the border region of the Amazonas and Roraima states and Venezuela. Recent research by Fiocruz found mercury traces in all 300 Yanomami individuals tested by researchers. High levels of contamination were also found among the Munduruku and Kayapo indigenous communities in the state of Pará.
The most damaging effects of mercury poisoning are on children. Mercury can be transmitted from a pregnant woman to her baby in the womb, and the newborn can suffer from rare neurological syndromes. In less severe cases, children may experience delays in neurological development, leading to learning difficulties.
“Perhaps the main impact is the deterioration of cognitive abilities in these generations of children born under the shadow of mercury contamination,” said Paulo Basta, who coordinates mercury contamination studies at Fiocruz, Brazil’s leading federal health research center. “Contrary to what entrepreneurs and politicians claim, that mining is a driver of socioeconomic development, it is actually an indicator of social inequality.”
A challenge that requires bold solutions
Experts assert that equipment already exists to reduce the risk of mercury contamination. The retort, for example, is a type of furnace where the mercury-gold mixture can be burned in a closed space, allowing the mercury to condense into liquid form within a safe container.
According to Jair Schmitt, director of environmental protection at the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA), it is rare to find anyone using such equipment. “Although there are techniques to minimize the release into the environment, almost all miners do not use these tools,” he told Mongabay.
There is also a cultural component at play. “People have always used mercury. It’s deeply ingrained,” said Rodrigues. He added that while it is possible to eliminate mercury by implementing more sophisticated machinery to separate gold from ore, there are no market incentives to do so. “Today, there are gold mines that produce gold without using mercury, but what incentive does someone have to do that? No market incentive.”
The Brazilian government is considering new laws to trace mercury and strengthen border controls. One bill even proposes banning its use in mining, following Colombia’s example.
