- Artisanal and small-scale gold mining in Brazil’s Tapajós River Basin emits 16 metric tons of CO2 per kilo of gold produced, and 2.5 metric tons of mercury annually, a study has found.
- Researchers suggest that recycling gold could dramatically reduce harmful emissions, along with other solutions such as formalizing mining, adopting clean technologies, and improving gold supply chain transparency.
- Economic dependence, mercury accessibility, and a demand for gold sustain small-scale gold mining, while enforcement risks pushing miners into ecologically sensitive areas.
- In November, Brazil launched a federal operation in the Tapajós Basin to expel illegal gold miners from the Munduruku Indigenous Territory, imposing millions of reais in fines to curb the damage caused by gold mining.
Decades of artisanal and small-scale gold mining in the Tapajós River Basin have left a heavy environmental legacy in the Brazilian Amazon: rivers contaminated with mercury, and high greenhouse gas emissions. Researchers are now proposing recycling gold as a sustainable alternative, one that could dramatically reduce these impacts and outperform even “green” gold mining, which focuses on more sustainable extraction methods.
The findings, presented at a sustainability conference in Japan in November, show that recycling used gold, particularly from high-value end-of-life sources like old jewelry, has the lowest environmental footprint, emitting as little as 22-50 kilograms of CO2 per kilogram of gold produced, according to data the researchers published in the journal Nature Sustainability in 2024. In comparison, artisanal and small-scale mining (ASGM) in the Tapajós River Basin generates approximately 16 metric tons of CO2 equivalent per kilogram of gold, but still less than the 21 metric tons produced by industrial operations.
“The carbon footprint is a fundamental problem in gold mining, both ASM and industrial mining,” study co-author Mario Schmidt, a professor of environmental management at Pforzheim University in Germany, told Mongabay. “Here, the only solution is recycling, although care must be taken to ensure that primary gold is not illegally mixed with recycled gold.”
Despite the carbon efficiency of recycling “scrap” gold, the relentless demand for newly mined gold persists, driven by economic and fashion pressures as well as cultural notions linking gold and wealth.
Gold prices have skyrocketed recently as demand remains high. The value of the metal increased by 28% in the third quarter of 2024 from the same quarter last year, hitting an all-time high.
“Physically, we are not short of gold,” Schmidt said. “But because gold is synonymous with money, humanity always wants more of it.” Tens of thousands of tons of gold already sit in banks and reserves like Fort Knox in the U.S., he said, yet new extraction continues, fueling environmental degradation.
The Mining Impacts Calculator, a tool designed to quantify the environmental costs of mining in monetary terms, sheds light on the scale of damage caused by carbon emissions from ASGM in the region around Brazil’s Tapajós River, a major tributary of the Amazon. According to Pedro Gasparinetti, an economist at the Conservation Strategy Fund who led the development of the calculator, gold mining in the area produced 75,752 metric tons of CO2 equivalent in 2020 alone, based on the figures in the 2024 study.
“Using a conservative carbon price of $110 to $160 per metric ton, this translates to an estimated $8 million to $11.6 million in damages,” Gasparinetti told Mongabay.
Mercury pollution is another significant consequence of ASGM, which uses this toxic metal to separate the gold from the ore. Each year, miners release at least 2.5 metric tons of mercury into the Tapajós region, contaminating waterways and soil, according to the study. Even with vapor-capturing retorts, miners still emit 0.19 kg of mercury for every kilo of gold extracted, exposing communities to toxic residues and harmful vapors.
The consequences of mercury pollution extend beyond the environment. Indigenous and riverine communities in the Tapajós River Basin, such as the Munduruku people, face severe health risks. Several studies carried out from 2017-2021 by the Oswaldo Cruz Foundation, Brazil’s leading public health research institute, revealed mercury contamination in every individual from three Munduruku villages, with 60% of women showing traces of mercury in excess of the World Health Organization’s safety threshold. Recent prolonged droughts, exacerbated by climate change, have forced many across the Amazon to rely on polluted rivers for drinking water, worsening the mercury crisis.
On Nov. 9, the Brazilian government launched an operation to expel illegal gold miners from the Munduruku Indigenous Territory, following years of inaction. The operation is seen as a critical step in addressing mining activities that have caused “extensive damage” to the area, according to an official report.
“The goal is to remove those engaged in illegal gold extraction and ensure the territory remains exclusively for the 9,257 Indigenous residents of the Munduruku, Isolados do Alto Tapajós, and Apiaká peoples,” the statement said.
Initial enforcement efforts have led to significant penalties: Brazil’s environmental protection agency, IBAMA, imposed 9 million reais ($1.5 million) in fines, while ICMBio, the agency responsible for protected areas, imposed an additional 20.27 million reais ($3.37 million). Authorities also seized thousands of liters of diesel fuel and mining equipment, resulting in an estimated 44.5 million reais ($7.4 million) in losses to the illegal operators.
The mercury crisis extends throughout Brazil and across other Amazonian countries. In the Yanomami Indigenous Territory, about 1,200 kilometers (750 miles) to the north of the Munduruku reserve, research by the Oswaldo Cruz Foundation found that nearly 92% of Indigenous inhabitants tested had mercury levels exceeding safe thresholds. In Peru’s Cenepa River, mercury-contaminated sediment and water jeopardize the health of the Awajun people, who depend on fish as a dietary staple.
“When we eat fish, we get strong allergies and stomach issues,” Felicio Sakash, a former leader of the Awajun community, told Mongabay in January 2024.
Providing mining alternatives
Efforts to enforce environmental regulations in the Amazon will fall short without viable economic alternatives to artisanal and small-scale gold mining, experts told Mongabay. In the Tapajós region alone, gold mining directly employs 35,000 people and indirectly supports thousands more. Many miners, including migrant workers, live in precarious conditions and rely on self-built infrastructure, from electricity systems to schools, according to Carlos de Matos Bandeira Júnior, a social science researcher at the Federal University of Western Pará.
“For many people, mining is the only source of income,” he told Mongabay.
Attempts to ban ASGM outright risk unintended consequences, such as driving miners into more remote, ecologically sensitive areas, according to the 2024 study. Such displacement often heightens conflicts with Indigenous groups and increases the difficulty of enforcing environmental regulations.
“Prohibiting mining outright is nearly impossible,” said Bandeira, who wasn’t involved in the study. “The industry ranges from small, individual operations to large-scale enterprises. Without viable alternatives, enforcement often hits the poorest workers hardest, leaving them without options.”
Cleaner technologies, such as mercury-free extraction methods, offer promising solutions but are often too expensive for most miners to adopt. Additionally, there’s limited support to help mining communities transition to other sources of income or adopt more sustainable practices.
“What I don’t see are alternative economic opportunities being offered to these people,” Bandeira said. “Many organizations hesitate to engage with mining communities for fear of reputational harm, and there is a clear lack of public investment.”
Other economic activities, such as sustainable agriculture, ecotourism and forest restoration, have shown promise in reducing reliance on mining. However, they face numerous barriers, including insufficient funding and limited scale.
“Some initiatives are beginning to explore alternatives, leveraging the expertise of local communities in areas like agriculture,” Bandeira said. “But these efforts are still in their infancy.”
Community-driven solutions, such as education campaigns, involving locals in decision-making processes, and enforcing stricter environmental standards, are seen as crucial to addressing the challenges posed by ASGM. Bandeira emphasized the complexity of the situation: “The road to sustainable mining is complicated. Without viable alternatives, enforcement alone will continue to fall short, leaving communities and ecosystems at risk.”
Making gold greener
Recycling gold, while promising, is not without its challenges. The industry suffers from a lack of transparency, with concerns that refineries may mislabel newly mined gold as recycled, undermining consumer trust and threatening the credibility of green gold certifications, according to the research presented in November. “We cannot tell just by looking at the gold itself where it comes from,” Schmidt said.
Yet, according to the World Gold Council, gold recycling is up 11% from 2023 and represents a quarter of the world’s supply.
Stricter certification standards and traceable supply chains are essential to uphold the credibility of sustainability claims, the study says. Additionally, industrial recycling of electronic waste to extract the minute quantities of gold inside, while less damaging than mining, often involves combustion of plastics and smelting processes that release carbon emissions. Informal recycling practices, such as open burning, worsen these issues by releasing toxic waste and untreated pollutants into the environment.
Addressing ASGM’s environmental and social challenges requires coordinated global action. Initiatives like the U.N.’s Minamata Convention on Mercury offer frameworks for reducing mercury use and urge countries to phase out its use in products, ban the opening of new mercury mines, and limit its emission into the environment.
“ASGM is one important issue in the [Minamata] convention, with article 7 requiring countries to draft National Action Plans (NAPs) for handling and reducing mercury usage in ASGM,” according to the 2024 study. “But implementation has been slow as gold from ASGM is an economic factor and mercury still plays an important role here.”
Tackling the illegal mercury trade, which accounts for up to 73% of the supply used in Brazilian gold mines, is equally critical. The mercury mostly comes from neighboring countries like Bolivia and Guyana, and its use in gold mining lacks a legal source, according to a 2023 report by the Escolhas Institute. IBAMA, the environmental agency, has confirmed that almost all the mercury used in mining operations originates from illegal markets.
A unified gold industry, with stricter ethical sourcing standards and enforcement mechanisms, could mitigate the environmental and human costs of gold production, Schmidt said. “Gold mining must be more strictly controlled, and the supply chain must be more closely monitored,” he said. “The gold industry must come together to take internationally coordinated action here and exclude ‘black sheep’ from trading.”
Banner image: A typical artisanal small-scale gold mining operation in the Amazon Rainforest. Image courtesy of Mario Schmidt.
Brazil tackles illegal miners, but finds their mercury legacy harder to erase
Citations:
Fritz, B., Peregovich, B., da Silva Tenório. L., da Silva Alves, A. C., & Schmidt, M. (2024). Mercury and CO2 emissions from artisanal gold mining in Brazilian Amazon rainforest. Nature Sustainability, 7, 15-22. doi:10.1038/s41893-023-01242-1
Bandeira Junior, C. M., & Carvalho, L. G. (2023). Transformations in artisanal and small-scale gold mining work and production structures in the Tapajós region of Brazil’s Amazon. Resources Policy, 83. doi:10.1016/j.resourpol.2023.103597
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