According to new research, a section of pristine rainforest contains the greatest levels of atmospheric mercury poisoning yet discovered. A multinational study team analyzed mercury levels near tiny and artisanal gold miners in the Amazon jungle and published their findings in Nature Communications. It’s previously known that these small-scale mining, which is mostly unregulated or illegal, emit more mercury than coal-burning power plants. The scientists intended to find out how much harmful mercury the woods were catching and storing by analyzing samples of air, leaf litter, soil, and leaves from the tops of trees in mining areas, pristine areas, and areas with low tree density.
“We discovered that mature Amazonian forests near gold mining capture significant amounts of atmospheric mercury,” said Jacqueline Gerson, who led the research as part of her at Duke. “More than any other ecosystem in the world previously investigated.” Because mercury binds the gold, illegal miners use it to extract gold particles from river sediment. The pellets are then large enough for the miners’ sieves to catch them. After that, the pellets must be heated in open fire ovens. The gold melts and is kept, while the mercury burns off and becomes atmospheric mercury, which is then absorbed by the neighboring rainforest’s leaves and soil.
The more mercury clung to the canopy, the more it stuck to the team. The researchers wrote in their paper that “intact forests in the Peruvian Amazon near gold mining get extraordinarily high mercury inputs and experience higher total mercury and methylmercury in the atmosphere, canopy foliage, and soils.” “For the first time, we show that an undamaged forest canopy near artisanal gold mining intercepts considerable amounts of particulate and gaseous mercury,” the researchers write.
By testing mercury levels in the wings of three distinct varieties of songbirds, the team was able to determine how mercury was hurting biodiversity. The scientists discovered 3-12 times more mercury in the feathers of birds at the Los Amigos Biological Station, where levels of atmospheric mercury pollution were unusually high, than in the feathers of birds in sections of forest far from these gold mines.
Mining activities, which are frequently associated by deforestation, are already known to harm biodiversity hotspots, reduce diversity, and result in elevated mercury levels in predators and humans. Gold is in high demand, which is driving the search for it into new territory. The crew claims that their goal is not to shut down the mines, but to protect persons who are involved in or near the mining, as well as wildlife and the environment.
“There’s a reason people mine,” Gerson explained. “Because mining is such an essential source of income, the goal isn’t to entirely eliminate it, nor is it for individuals like us from the United States to be the ones imposing answers or deciding what should happen.” “The idea is to emphasize that the challenges are far broader than water pollution, and that we need to collaborate with local people to find solutions for miners to have a sustainable livelihood while also protecting indigenous communities from air and water poisoning.”
While mercury being collected by the canopy is not a good thing, as wildlife contamination has proven, it may be shielding Earth from a more serious catastrophe. “These trees are performing a tremendous job by catching a significant portion of this mercury and keeping it from entering the global atmospheric pool,” said Emily Bernhardt, a Duke Professor of biology. “This emphasizes the importance of not burning or deforesting them, as this would release all of the mercury back into the atmosphere.”
