The Munduruku people of Brazil are confronting a silent yet devastating threat—mercury poisoning—linked to illegal gold mining in their ancestral lands. Community leaders report alarming rates of miscarriages, neurological disorders, and sensory impairments, exposing the human cost of the environmental crisis.
For centuries, the Munduruku have lived along the Tapajós River, spanning the modern Brazilian states of Amazonas and Pará. Their lives and culture are intimately tied to the river, which provides food, water, and sustenance. But in recent decades, mysterious and severe health issues have plagued the community: children unable to lift their heads, adults struggling to walk, muscle tremors, memory loss, fading vision and hearing, and repeated miscarriages.
Researchers have now traced the cause to the very lifeblood of the Munduruku—the Tapajós River, heavily contaminated with mercury.
Mercury poisoning is notoriously difficult to diagnose, often mimicking degenerative conditions such as Parkinson’s or Alzheimer’s disease. Gabriela Arrifano, a professor of mercury toxicology at the Federal University of Pará, explains:
“There is now enough evidence to link the symptoms observed in riverside communities directly to mercury exposure. It is highly likely that mercury is responsible for many of these health crises.”
The source is clear. Professor Arrifano notes, “We have robust evidence that mercury contamination in the environment stems from illegal gold mining activities.” Her lab analyzes hair and blood samples from affected residents, revealing alarming levels of the toxic metal.
Among those affected is Alessandra Korap, who recounts how mercury exposure is devastating Munduruku women’s fertility. “At first, I didn’t even know what mercury was,” she admits. Today, she and her community face the harsh reality of reproductive health compromised by environmental contamination.
The Deadly Gold Rush
Gold mining is illegal in indigenous territories across Brazil. Yet, lucrative gold prices have drawn miners into the heart of the Amazon, leaving the forest scarred with orange and red craters. Illegal operations churn up riverbeds, releasing mercury—a substance that binds to gold—into the air, soil, and water.
The contamination travels swiftly through the ecosystem. Fish in mercury-laden waters accumulate the metal in their tissues, entering the diet of indigenous communities. Studies have found that one in five fish sold in northern Brazilian markets contains dangerous levels of mercury. Once ingested, mercury enters the bloodstream and can reach the brain, causing lasting neurological damage. Even low levels of exposure disrupt the body’s reproductive, nervous, and sensory systems, shrinking visual fields and impairing hearing.
Alessandra recalls the early days of the crisis. “My symptoms are mild—tingling in my hands, forgetfulness, brain fog—but I know it is because of mercury.” She suspects that historical exposure, passed down from previous generations of fishermen, may have compounded the problem for many children. Mercury also accumulates in placentas and breast milk, putting infants at even greater risk.
Government Crackdown and Challenges
The Brazilian government under President Luiz Inácio Lula da Silva has intensified efforts to halt illegal mining. The environmental agency IBAMA has targeted mining sites, destroying equipment, seizing assets, and removing the presumption of “good faith” for gold sales. These interventions have yielded tangible results: in the Yanomami Indigenous Territory, federal data show a 94% reduction in illegal mining activity between 2023 and 2025.
Yet, the battle is far from over. Miners are relocating, gold prices continue to soar, and criminal networks persist, intertwining mining with drug trafficking and money laundering. Officials admit that the crackdown, though significant, struggles to keep pace with market incentives and criminal ingenuity.
A Global Challenge
Mercury contamination is not confined to Brazil. Across South America and parts of Africa, illegal gold mining threatens ecosystems and human health. Rising gold prices and geopolitical uncertainties drive miners into vulnerable areas, while criminal groups increasingly exploit these high-risk operations. Julia Yansara of the Financial Accountability and Corporate Transparency Coalition warns:
“The economic allure of gold is pushing illegal miners into new territories, drawing in criminal actors and deepening the public health crisis.”
For the Munduruku, the consequences are immediate and personal. Communities face the heartbreaking reality that everyday survival—the fish on their plates, the water from their rivers—has become a source of disease and reproductive risk. As Alessandra Korap reflects, the shadow of mercury hangs over their futures: “Women are afraid to get pregnant. Every meal, every fish, carries a hidden danger.”
The struggle of the Munduruku is a stark reminder that environmental crimes are also human tragedies, demanding urgent attention, rigorous enforcement, and global awareness.