Miners in Peru may be risking more than the value of the gold they’re digging for.
Research led over the course of two years by Jennifer Swenson, assistant professor the practice of geospatial analysis in the Nicholas School of the Environment, revealed that as gold prices have increased, so have deforestation and the deposition of mercury in the atmosphere and water sources in the Amazon—particularly Peru, where the research was conducted. The deposits pose dangerous health risks for miners.
“We knew that there was a lot of uncontrolled gold mining just by reading the papers,” Swenson said. “It looked like it was [on] a pretty grand scale, so that’s what made me go in and download the satellite images. And I found that they’re tearing up the forests and poisoning the waterways with mercury at a pretty alarming rate.”
Assisting with the imagery was Catherine Carter, Nicholas ’10 and an environmental scientist with consulting firm Tetra Tech Inc. Carter said she took a course on remote sensing taught by Swenson in which she focused on image analysis. Through these images, it became clear to the research team that huge plots of land were being torn up for mining. Nicholas School professor Jean-Christophe Domec explained in an email Thursday that the yields for gold are low, so large expanses of forest need to be destroyed to acquire small quantities of the precious metal.
Swenson said the gold mining process depends on mercury—the substance at the root of the health problems.
“They use it to separate the gold because it amalgamates with the gold, but a whole bunch is washed off and it goes into waterways and sediments,” she said. “To separate the gold from the mercury... they burn the mercury off and that goes into the atmosphere.”
In addition to the toxicity being created in the air and in water sources, she noted, miners are often breathing in mercury directly as they blowtorch it off the gold.
Swenson noted that these consequences are difficult to control because of the nature of gold mining in Peru.
“The majority of the mining in the region is artisanal in nature and most of it is unregulated,” she said. “Nobody really knows which mines actually have legal claims.... People just tend to mine where there’s gold. It’s remote rainforest. Most of the mining rights aren’t processed yet.”
Deforestation has led to a number of negative consequences, both locally and on a broader scale, Carter added.
“With deforestation there’s always concerns about carbon released into the atmosphere... promoting climate change,” she said. “Whether the amount [of carbon] we’re seeing in Peru from gold mining will contribute to that in a significant amount, I’m unsure, but more important is the habitat that [the] forest provides for biodiversity. So if deforestation is occurring there and these critical habitat areas are being fragmented, it’s a threat to biodiversity.”
In addition, Carter said she is especially concerned about the contamination of water, particularly in the nearby town of Puerto Maldonado.
“A huge concern of mine is water quality and the job I have right now is focused on surface water management,” she said. “[I’m concerned about] how their fish consumption is leading to mercury contamination in the humans.... It’d be cool if more studies could be done on that.”
Swenson pointed to the difficult situation faced by the people mining in Peru. She said that the majority of the Peruvian miners are likely poor migrants who have few options for employment besides prospecting.
“I haven’t seen... data on this, but they’re getting flakes of gold,” she said. “They’re not getting rich nuggets so I don’t know if anyone’s getting rich, but they’re surviving. So it’s a tough decision, because if you take that means of surviving away I’m not sure what their next jobs [are] going to be. It’s a sticky issue.”