Bronx, NY, February 20, 2026— Across the Amazon Basin, the rapid expansion of illegal and artisanal gold mining is contaminating rivers, wildlife, and Indigenous communities with mercury—a toxic heavy metal that acts as a potent neurotoxin and is used to extract gold from crushed ore. The Wildlife Conservation Society (WCS) is working with partners in Ecuador and Bolivia to help communities resist illegal incursions, adopt mercury-free alternatives, and use science and legal action to defend their rights and health.

WCS has produced a special edition of its Wild Audio podcast that captures that work. Listen to the episode here.

In artisanal and small-scale gold mining, crushed ore is typically mixed with liquid mercury, which binds to gold particles. The amalgam is then heated—often in rudimentary containers over open flames—causing the mercury to vaporize and leaving behind a lump of raw gold known as doré. 

“When you burn the mixture and release the mercury, it’s highly toxic,” said Sebastian Valdivieso, WCS Ecuador Country Director. “It enters the body through the lungs and is extremely dangerous. Experts can detect traces of mercury on tree leaves. That mercury washes back into rivers and enters the food chain.”

Unlike large-scale industrial operations, smaller-scale mining often functions informally, with little regulatory oversight. In many cases, illegal operators move into Indigenous territories offering equipment, money, and protection—along with weapons and social disruption.

“You have a community with gold on its lands, and then miners arrive with a full package—technology, money, protection, and also guns and social problems,” Valdivieso said. “They impose an extraction model by force.”

WCS is working to ensure communities have a viable alternative. Through community-based natural resource management, WCS supports local leaders who wish to explore mercury-free gold extraction approaches or alternative income streams that protect forests, rivers and Indigenous rights.

In Bolivia, Indigenous organizations—supported by WCS—have demonstrated how science and constitutional law can hold authorities accountable for mercury contamination in the Madidi landscape. Indigenous technicians trained in strict scientific protocols collected more than 300 hair samples from people in 35 communities. Laboratory analysis revealed that approximately 75 percent exceeded internationally recognized health limits for mercury exposure.

“We focused on human health because it was the most concrete and measurable way to demonstrate harm,” said WCS Bolivia conservationist Oscar Loayza. “When you talk about health, the message hits differently. You’re no longer discussing polluted water or deforestation—you’re talking about people being slowly poisoned.”

The resulting constitutional legal action secured a favorable court ruling and has become a model for other regions—demonstrating how law, science, and communication can work together to defend rights and ecosystems.

The research also revealed how mercury accumulates in fish species central to local diets. Predatory fish higher in the food chain were found to contain elevated mercury levels, while frugivorous species had much lower concentrations. WCS is working with fishers to share this information so they can protect both public health and livelihoods.

“Mercury has become a bridge—a way to show the human dimension of mining’s impacts,” Loayza said. “It helps society understand that this is not just an environmental issue, but a human rights issue.”

Illegal mining also drives deforestation, river sedimentation, and the breakdown of community governance. It threatens ecotourism economies and undermines cultural traditions. Across the region, WCS is investing in youth leadership and communication training so the next generation can defend their territories with knowledge and voice.

Matthew Linkie, Technical Director for WCS’s Andes, Amazon, and Orinoco Region, emphasized the broader importance of community leadership. “Across the Amazon, communities are on the front lines,” Linkie said. “By strengthening local governance, building scientific capacity, and supporting human rights, we can help defend biodiversity and human health together.”

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