'Amazon’s toxic time bomb': How trees reveal the invisible scars of gold mining
Produced by: Mohsin Shaikh
Toxic Legacy
Mercury, used in illegal gold mining, leaves no visible mark—but it's poisoning air, land, and water across the Amazon and beyond.
Tree Witnesses
In a twist of nature, trees like Ficus insipida absorb mercury from the atmosphere, preserving its history in their growth rings.
Pollution Clues
Researchers found wild fig trees near mining towns carried the highest mercury loads—offering a silent map of contamination hotspots.
Hidden Burn
Miners burn mercury to extract gold, releasing a neurotoxin. This process, though unseen, now outpaces coal plants as a global pollutant source.
Atmospheric Echo
“The tree is just reflecting what the atmosphere is doing,” says Cornell’s Jacqueline Gerson, who led the mercury-ring research.
Time Travelers
Tree rings offer a year-by-year record of mercury exposure. Near mining sites, spikes appeared post-2005—tracing the rise in illegal mining.
Policy Compass
Tree data could help target intervention zones, guiding bans, clean-up efforts, and safer mining technologies where they're needed most.
Cut-Off Concern
The U.S. recently halted funding to key Amazon pollution research—a move researchers call dangerous in the face of global mercury spread.
Borderless Crisis
Wake Forest’s Luis Fernandez warns artisanal mining is more than local—it corrupts economies and crosses borders with toxic consequences.