The Amazon dry season runs roughly from June to October. River levels drop, forest tracks become passable, and heavy machinery can reach deep into the interior. It is the easiest season for illegal gold mining — and, for the same reasons, the easiest season for enforcement. Mercury-based mining is no longer treated as a domestic matter for any single country: it moves along rivers and across borders. So how far has the regional framework for dealing with it actually got?
What moved was policing, not diplomacy
Over the past year, no new treaty or joint declaration dedicated to stopping illegal gold mining has been signed among Amazon countries. The hard numbers came instead from law enforcement.
In January 2026, INTERPOL announced the results of Operation Guyana Shield, in which authorities from Brazil, Guyana, Suriname and French Guiana jointly carried out more than 24,500 checks on vehicles and individuals, leading to 198 arrests. Machinery, raw gold, drugs, cash and cylinders of mercury hidden inside solar panels were seized. Suspected human trafficking and labour exploitation surfaced alongside the mining itself, according to INTERPOL.
The groundwork was laid in November 2025, when Brazilian authorities, again with INTERPOL support, disabled 277 floating dredges used for illegal extraction on the Madeira and other rivers. That operation ran through CCPI Amazônia, the Amazon International Police Cooperation Centre, which brings together police from Brazil, Bolivia, Colombia, Guyana, Peru and Suriname. If cross-border cooperation is becoming real anywhere, it is at this policing layer first.
The day in Brasília that started it
The usual reference point for the regional strategy is a workshop held in Brasília on 18 June 2025. It was hosted by Conservation Strategy Fund (CSF) together with Brazil's Federal Public Ministry (MPF) and the Amazon Cooperation Treaty Organization (ACTO, or OTCA in Spanish). Seven countries took part: Brazil, Peru, Bolivia, Colombia, Ecuador, Suriname and Venezuela.
The tool presented there was the Mining Impacts Calculator, which estimates damage from deforestation, river sedimentation and mercury pollution and converts it into monetary terms usable in policy and litigation. Because each country had its own way of proving damages in court, simply having a shared yardstick matters. But on CSF's own account, the meeting produced no binding agreement — it identified shared priorities and possible areas for cross-border collaboration, and no more.
Where the mercury comes from
Amazon countries produce almost no mercury of their own, so whatever is being used has been brought in. A report published by the Environmental Investigation Agency (EIA) in July 2025 documented the smuggling of at least around 200 tonnes of illegal mercury between April 2019 and June 2025 — the largest such flow ever recorded, starting from mercury mines in the Mexican state of Querétaro and moving through the Pacific port of Manzanillo. EIA alleges some of those mines are controlled by organised crime. On a conservative estimate, that mercury was used to extract at least US$8 billion worth of illegal gold.
Acting on EIA intelligence, Peruvian customs seized roughly four tonnes of Mexican mercury in June 2025 — reportedly the largest seizure ever made by an Amazonian country. Set against 200 tonnes, it also shows how little of the flow is being intercepted.
The full picture of contamination is still missing. ACTO, working with the Global Environment Facility (GEF) and the UN Environment Programme (UNEP), with research by France's Institut de Recherche pour le Développement (IRD), is compiling a "Panorama on Mercury Contamination in the Amazon Region": a georeferenced inventory of emission sources and risk areas. ACTO itself acknowledges that import volumes and routes are barely known. The numbers that regulation would have to rest on are not yet in place.
The paperwork loophole outside the raids
Seizures on the ground are not enough. An investigation published by Greenpeace on 28 May 2026 analysed 187 mining permits issued by Brazil's mining agency ANM near Indigenous lands and protected areas, and found no sign of mining at all in 98 of them. Those "ghost permits" were nonetheless used to justify the sale of 26.8 tonnes of gold, worth an estimated US$3.88 billion, between 2018 and March 2026. Researchers believe much of that gold in fact came from protected areas and Indigenous territories.
The mining frontier itself is on the move. In Peru, extraction has pushed beyond its long-standing centre in Madre de Dios into Loreto and Ucayali to the north and centre-east, driven by high gold prices — a story covered in an earlier piece on Peru's advancing frontier. This article is about something different: not one country's frontier, but the framework through which seven countries are trying to grip the flows of mercury and gold together.
The difficulty: dry season in a year of transitions
Two things make this hard. The first is that enforcement tends to be a one-off. Officials arrive, destroy equipment, and once they withdraw the miners return — reporting from the field describes this cycle repeatedly. The dry season is a window for enforcement, but it is also peak earning season for the miners.
The second is the political calendar. Peru's new government takes office on 28 July with faster mining permitting among its stated priorities (see our piece on the three challenges awaiting it). Colombia's new government follows on 7 August, having campaigned on expanding oil and extractive industries (see our piece on opening the Amazon to drilling). Regional cooperation rests on each country's environmental diplomacy, so how these two shifts land on ACTO's cohesion is the thing to watch for the rest of the year.
My perspective
When following this story through numbers, I try not to confuse arrest counts with flow volumes. 198 arrests, 277 dredges disabled, four tonnes seized — all real results, but all outputs of enforcement rather than measures of how much contamination has fallen. Alongside them sit numbers of a different kind: the 200 tonnes of mercury EIA traced, the 26.8 tonnes of gold Greenpeace flagged. Those are denominators, and the two sets have not been connected.
That is exactly why work like the ACTO/GEF/UNEP mercury panorama matters — it measures the denominator. Whether the cross-border framework has become real will not be decided by the number of declarations, but by whether these countries can produce emission and inflow figures on a shared yardstick. Whether prosecutors actually adopt the Mining Impacts Calculator is a test of the same kind.
Three indicators to follow: how many joint operations run under CCPI Amazônia during this dry season (June–October); when the ACTO mercury panorama results are presented to member states; and whether Brazil's ANM moves to review mining permits in response to the ghost-permit findings. Only when all three line up can we say seven countries are treating this as one river's problem.
Glossary
OTCA / ACTO = Amazon Cooperation Treaty Organization, the intergovernmental body founded on the 1978 Amazon Cooperation Treaty, with eight members: Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname and Venezuela. ASGM = artisanal and small-scale gold mining. draga = a floating dredge that sucks up riverbed sediment. mercurio = mercury — a word you will meet constantly in Latin American environmental coverage.
Arrest counts measure enforcement, not cleaner rivers. The framework only becomes real once someone starts measuring the denominator.
References
- Building a Regional Strategy to Address Gold Mining in the Amazon | Conservation Strategy Fund — conservation-strategy.org
- 198 arrests in cross-border illegal gold mining operation in South America | INTERPOL — interpol.int
- Brazilian authorities dismantle hundreds of illegal dredges in major anti-mining operation | INTERPOL — interpol.int
- Toxic Tons: The Largest Flow of Illegal Mercury to the Amazon Exposed | Environmental Investigation Agency — eia.org
- Study will provide a regional overview of the mercury pollution situation in the Amazon Basin | OTCA — otca.org
- Illegal miners extract billions in Amazon gold despite Brazil crackdown, Greenpeace finds | Mining Weekly — miningweekly.com
※ This article is the author’s commentary based on public information. Please confirm the latest figures, dates and procedures with governments and primary sources. Quotations are kept minimal and sources are cited.