Gold Mining Turning Peruvian Amazon Into Mercury Sinks

When thinking about mercury pollution in the environment, it is common to think about industries that use mercury at some stage of production, or even natural sources such as volcanoes. While that may be true, the source of present-day mercury pollution in Peru is small yet serious – illegal gold mining. According to a new study, illegal gold mining activities in the Peruvian Amazon are leading to levels of mercury pollution that could rival mercury mining-related industrial areas.

Aerial view of eastern Peru's gold pits with Inambari river flowing on the left.
Aerial view of gold prospecting pits in eastern Peru. Image Credits: NASA

How does gold mining lead to mercury pollution?

Gold mining, especially illegal, small-scale, or artisanal mining, involves mercury. In the initial stages, gold particles need to be collected from river sediments. Mercury is used to ease this process. Mercury attracts gold and forms an amalgam, or a bind, with it.

Once this gold is collected using mercury, the two need to be separated to collect gold. This is done by melting the amalgam over open fire ovens. This step melts the gold to be collected, while the mercury turns to smoke and is released into the air.

Where does the mercury smoke go?

Once released into the atmosphere, the mercury can stay in the air and may make its way into the flora and fauna of the region, including human bodies. Furthermore, the rain washes it down into the earth again, leading to mercury being collected in the soil, trees, and more.

Mercury Pollution in Peruvian Amazon

Mercury pollution from gold mining in water bodies has already been noted. The new study focused on pollution by studying the air, soil, leaf litter, and leaf surfaces from the tops of the trees. It was found that areas with a denser tree canopy held more mercury than areas with scraggly trees, or deforested areas. The study concluded that the mercury levels were directly proportionate to the leaf area index.

“We found that mature Amazonian forests near gold mining are capturing huge volumes of atmospheric mercury, more than any other ecosystem previously studied in the entire world,” said Jacqueline Gerson, lead author of the study.

“These forests are doing an enormous service by capturing a huge fraction of this mercury and preventing it from getting to the global atmospheric pool. It makes it even more important that they not be burned or deforested, because that would release all that mercury back to the atmosphere,” added Emily Bernhardt, professor of Biology at Duke University and one of the authors of this study.

They also studied the accumulation of mercury in the feathers of three songbird species, both near the mining activity and at a distance. Birds in these areas had up to 12x higher mercury accumulation than birds at other areas. The average mercury found in these birds was 3x higher.

The researchers also point out that such mining activity is not only common in the area, but also a significant source of local livelihood. Artisanal gold mining here, as in many places, is motivated by economic needs.

“There’s a reason why people are mining. It’s an important livelihood, so the goal is not to get rid of mining completely, nor is it for people like us coming in from the United States to be the ones imposing solutions or determining what should happen. The goal is to highlight that the issues are far vaster than water pollution, and that we need to work with local communities to come up with ways for miners to have a sustainable livelihood and protect indigenous communities from being poisoned through air and water,” said Gerson.

The results of this study have been published in the Nature Communications journal.


Terra Love View All →

I am a simple writer who wishes to use her skill to create more awareness about the planet that offers us life.

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