Rising world gold prices have spurred the expansion of illegal gold mining throughout the Amazon River basin, with criminal gangs and ordinary citizens seeking livelihoods causing widespread environmental damage as they dig and dredge the rainforest region. In this Centerpiece, EcoAméricas correspondents provide perspectives from two countries—Barbara Fraser on the growing public health threat illegal mining operations are posing in Peru, and Christina Noriega on reports of government complicity in the surge of black-market mining in Venezuela.

Peru
A recent report on mercury levels in people living along two rivers in Peru’s northeastern Loreto region has renewed concerns about the risks of exposure to the toxic metal, even in remote areas of Amazonia. The study, conducted in 2024, found mercury levels exceeding thresholds recommended by the World Health Organization, especially in children and women of child-bearing age.

Although the study does not pinpoint the mercury’s origin, those rivers have seen a recent boom in illegal gold mining, which involves use of large amounts of mercury to separate gold from sand and sediment dredged from river beds. Mercury causes neurological damage and is especially hazardous for young children whose neurological systems are developing. In pregnant women, it can affect the fetus.

In the environment, bacteria convert metallic mercury into a form that accumulates in fish, with concentrations that increase up the food web as, for instance, large fish eat smaller fish. Health risks are high in remote villages where fish are the main source of protein. The high levels in children and women of child-bearing age mean “there could be strong impacts for future generations,” says Claudia Vega, head of the mercury program at the Center for Amazonian Scientific Innovation (Cincia) at Wake Forest University in the U.S. state of North Carolina, which conducted the study.

The researchers went to Loreto and analyzed hair samples from 166 people in three communities along the lower Putumayo River and 273 people in six communities along the Nanay River and one of its tributaries, the Pintuyacu. The Nanay is the main source of drinking water for Iquitos, a city of around 600,000 people. They also analyzed sediment samples from those areas, as well as fish collected near the communities and in markets in Iquitos.

Mercury levels in fish sampled in the two areas of the Cincia study were similar to those found in Peru’s southeastern Madre de Dios region, which has been the country’s epicenter of alluvial gold mining since the 1990s. The concentrations found in people, however, were much higher in the two areas of Loreto than in Madre de Dios.

The researchers say that is probably because fish make up a larger part of the diet in Loreto, where fish consumption averages 51.6 kilos (kg) per person annually, compared to 15.4 kg nationally. In rural areas, where fish are the main protein source, consumption can reach 100 kg per person annually. Mercury levels in human hair were generally higher in the Putumayo study sites than in the Nanay and Pintuyacu communities, probably because the Putumayo villages are farther from towns where people can obtain protein from sources other than fish.

Overall, 97% of the study group had mercury levels significantly higher than the World Health Organization’s recommended maximum of 2.2 mg/kg of body weight. On the lower Putumayo River, 81% of women of child-bearing age had mercury levels that could pose a health risk. Along the Nanay and Pintuyacu rivers, children under age 5 showed particularly high levels.

In presenting the study results to community members, the Cincia team emphasized that people can reduce their mercury exposure by eating smaller fish and fish that are herbivorous, rather than piscivorous. Because people eat whatever they catch, she says, “it’s important to work more with them, because depending on fishing technique or where you fish, you know more or less what type of fish” will be caught.

The surge in world gold prices in recent years has driven an influx of miners throughout the Amazon basin, where tens of millions of years of erosion from the Andes Mountains have left the rainforest region’s riverbeds laced with tiny flecks of gold.

Rivaling the drug trade

The international market price of gold, which was less than $500 an ounce in the late 1990s and early 2000s, spiked to nearly $2,000 after the 2008 global economic crisis, dropped slightly, then surpassed $3,500 this year, making alluvial gold mining in Amazonian countries even more lucrative than the drug trade.

Attitudes toward mining tend to be mixed in communities, with some people opposing the activity because of the environmental and health impacts and links to organized crime and violence. Other communities face internal conflicts over mining, which provides an income previously unimaginable in a region where jobs are scarce and climate change increasingly upends subsistence farming and fishing.

And while studies like Cincia’s point to mercury health impacts that could affect generations of children, the rising international prices fueling the gold rush also drive a lucrative black-market mercury trade. The Minamata Convention on Mercury, which took effect in 2017, aims to reduce and eventually eliminate mercury use. But the July 2025 seizure in a Peruvian port of a record four tons of mercury—a shipment originating in Mexico and bound for Bolivia—points to black-market trade that undermines the international treaty.

Traffickers procure mercury

In a study released in July, the Environmental Investigation Agency, a nonprofit watchdog with offices in London and Washington, D.C., reports that between April 2019 and June 2025, at least 200 tons of mercury from mines in the Mexican state of Querétaro fueled production of some $8 billion worth of illegal gold in Peru, Colombia and Bolivia. The organization found drug-trafficking groups involved in the mercury exports, which were concealed by missing or underreported figures in official statistics.

The Environmental Investigation Agency report urges parties to the treaty, who will meet in early November, to close loopholes that allow continued mercury use in the kind of mining that is exploding throughout the Amazon.

Meanwhile, Vega urges closer monitoring of mercury levels in fish and in people in Loreto, as well as action to spare Peru’s northern Amazon region from the devastation caused by mining in Madre de Dios.

“There’s still time,” she says, adding that the initial study of mercury levels in the communities in Loreto is a snapshot, and further monitoring is needed “to see what is happening, to take action before the situation gets worse.”

Venezuela
The Venezuelan Amazon, the biodiversity-rich rainforest ecosystem that spans half of this South American country, has come under immense pressure from criminal groups that, in league with Venezuelan government forces, are transforming the delicate biome into lucrative mining sites.

A recent report from the International Crisis Group, a research nonprofit that monitors conflicts around the world, finds rising gold prices and Venezuela’s continued economic turmoil are driving the illegal operations in the region with devastating environmental consequences. “ Governmental elites and state forces are in cahoots with armed groups controlling these illegal gold mining pits,” Bram Ebus, the report’s author and an expert in environmental crime, told EcoAméricas.

Sources cited in the report said illegal gold mining in southern Venezuela expanded to 140,000 hectares (346,000 acres) in 2023, an increase of 59,000 hectares (146,000 acres) since 2018. While Venezuela encompasses only 6% of the Amazon basin, it now accounts for over 30% of illegal mining sites across the region, the International Crisis Group reports.

Experts place the blame in part on Venezuelan President Nicolás Maduro for dismantling environmental protections to encourage extractive activity that might stabilize Venezuela’s beleaguered economy. In 2016, Maduro issued the Orinoco Mining Arc Decree, opening up nearly 12% of the country, including protected areas and swathes of the Amazon rainforest, to the legal extraction of gold, diamonds, and coltan.

The decree aimed to attract foreign investors through state-backed mining partnerships. But foreign mining investment did not materialize as hoped due to the country’s economic and humanitarian crisis, and criminal groups filled the void.

Local gangs and Colombian guerrillas from the National Liberation Army (ELN) and dissident factions of the Revolutionary Armed Forces of Colombia (FARC) seized mining sites. Venezuelans hit hard by the economic recession also migrated south to gain a livelihood from the gold boom.

But after participating in the COP27 world climate conference in Egypt in 2022, Maduro appeared willing to address the crisis. That year, the military targeted illegal miners in the Imataca Forest Reserve, near the Guyana border, arresting 11 suspects. In 2023, state forces destroyed mining equipment in Yapacana National Park, and in 2024 they raided sites in Duida Marahuaca Park.

Maduro used the operations to project himself as an environmentally conscious leader; but in practice, the crackdowns did little to stop the expansion of illegal gold operations. Indeed, the Crisis Group report asserts the government’s aim had little to do with halting environmental destruction.

“ Maduro came back [from COP27] with a strategy of cracking down on illegal gold mining in the south with the pretension of environmental conservation, but with the real agenda of getting more of the illicit gold extraction under government control for illegal enrichment,” said Ebus.

Cristina Burelli, director of SOS Orinoco, a Venezuelan environmental organization, said that Venezuelan military commanders largely targeted miners who were not aligned with state forces. After the raids, they reportedly seized control of the illegal sites or demanded extortion payments and continued to operate the sites under government control.

“The operations weren’t against all illegal miners,” Burelli says. “Those allied with the government were left untouched.”

The kind of gold mining sweeping through southern Venezuela is largely informal and highly destructive. It uses mercury to separate the gold from sediments, polluting rivers and endangering public health, according to a 2024 report published by SOS Orinoco.

While Maduro has in recent years blocked studies on mercury contamination, the report referenced a 2010 study conducted in the Orinoco, Apure and Ventuari rivers, where 13 out of 18 fish species sampled contained high levels of mercury concentration. High mercury levels in fish were also found in the Cuyuní River in eastern Venezuela, according to a 2009 study.

The Crisis Group report raised special concern over the contamination of waterways in the Bolívar state, which supplies 90 percent of the country’s fresh water. It noted that illegal mining is rapidly expanding, now affecting almost 30 rivers in southern Venezuela. The number of rivers affected is up 106 percent compared to six years ago, the report noted.

Rising deforestation linked to mining is another concern. Deforestation in the Venezuelan Amazon hit a record 32,240 hectares (80,000 acres) lost in 2024, according to the Monitoring of the Andes Amazon Program, a research initiative that uses satellites to track land degradation.

“If you deforest an Amazon forest, the recovery is long-term,” said an environmental expert in Venezuela, who asked not to be named out of fear of retaliation. The expert added that forest loss also diminishes the Amazon’s capacity to regulate the continent’s climate and water cycle.

Ebus concluded that any “quick fix” to Venezuela’s mining crisis is unlikely given how intertwined it is with the broader economic and humanitarian crisis. Rising gold prices, which hit a record high of $3,508.50 per ounce in September, will only exacerbate the problem, he says.