Brazil is leveraging forensic science to combat illegal gold mining, a major driver of deforestation and mercury contamination in the Amazon rainforest. At the National Institute of Criminalistics in Brasilia, federal police operate a "gold lab" dedicated to analyzing gold samples and determining if they originate from protected areas.
This "gold fingerprinting" method, developed since 2019 in collaboration with Brazilian universities, uses sophisticated techniques like X-ray fluorescence spectrometry and scanning electron microscopy. The process identifies unique particle compositions within gold deposits, allowing investigators to match seized gold to its source. If a sample is found to have been mined in a protected national forest or Indigenous land, it signifies illegal extraction.
Gustavo Geiser, a federal police forensics expert, explained that the lab's work helps build cases against those involved in environmental crimes. These criminals often use fraudulent methods to introduce illegally sourced gold, as well as timber and cattle, into legal markets. A recent surge in global gold prices has intensified mining activities in the Amazon.
Estimates from Amazon Mining Watch indicate that approximately 496,000 hectares (1.2 million acres) of rainforest have been cleared for mining since 2023, with a significant portion in the Brazilian Amazon. Brazil's top audit institution has flagged evidence suggesting that mining permits issued to small-scale miners are being used to legitimize gold extracted from protected areas. A Greenpeace report detailed a "ghost mine" scheme where legal mine owners falsely claim large gold extractions from inactive sites while illegal operations occur nearby on Indigenous lands.
In response, a federal court in Para has ordered institutions like the Central Bank and the National Mining Agency to implement stricter controls and traceability for gold. Federal prosecutors have also filed a lawsuit against the National Mining Agency, aiming to improve oversight of mining permits, which they argue are being used to launder gold from protected territories.
Geiser noted that the gold lab's ability to verify legitimate origins strengthens global gold supply chains and financial markets. While specific numbers of arrests are unavailable, crime networks are reportedly expanding their laundering operations to neighboring countries, with samples from abroad now part of the lab's growing database.
Regional countries are enhancing collaboration through the Amazon International Police Cooperation Center to address this transnational crime. The Amazon's role as a crucial regulator of global climate means that degradation from mining can accelerate global warming.
MapBiomas, a nonprofit monitoring land use, reported that over 90% of Brazil's mining occurs in the Amazon, with nearly 40% being illegal. Although illegal gold mining is a smaller contributor to deforestation than agriculture, its environmental impact, particularly mercury contamination, is severe and difficult to reverse. Mercury used in gold extraction pollutes rivers, affecting water sources and fish essential for Indigenous communities. A 2023 study found that a significant percentage of fish in Amazonian markets exceeded safe mercury levels, with children being particularly vulnerable.
Brazil is a signatory to the Minamata Convention on Mercury, which aims to eliminate mercury use in gold mining. The Ministry of Mines and Energy is considering measures to phase out mercury, though consultation with affected Indigenous groups has not yet occurred. Geiser believes that a complete ban on mercury would not only curb contamination but also bolster forensic investigations, as his lab can detect mercury traces, clearly identifying illegal mining operations.