Midas & Mercury

The Capital of Biodiversity is facing a tsunami of toxic mercury. Spurred by rising prices, unregulated gold miners are flooding into a remote part of the Peruvian Amazon, clearing forests and contaminating the landscape with mercury used to extract the precious metal. And mercury releases could double this year alone, a new study predicts, as gold prices climb past $1,500 per ounce.

The Peruvian state of Madre de Dios covers about 85,000 square kilometers of Amazon lowland rainforest near the borders of Brazil and Bolivia. The region’s extraordinary biodiversity prompted the Peruvian government to officially dub it the “Capital of Biodiversity.” But it is the area’s mineral wealth that is attracting thousands of mostly poor, unregulated “artisanal” gold miners, researchers from the United States, France and Peru report in PLoS ONE. Madre de Dios is now Peru’s third largest source of gold, and researchers estimate it produces 70% of the nation’s artisanal gold. Globally, such artisanal mines have produced an estimated 20–30% of the world’s gold supply since 1998, and artisanal mines are believed to be responsible for one-third of all mercury released into the environment — and average of 1,000 tons per year.

To understand the causes and consequences of this modern Midas touch, the researchers analyzed world gold prices, satellite images of deforestation in two heavily mined parts of Madre de Dios, and Peru’s mercury imports. In general, they found that deforestation and mercury imports have risen in concert with gold prices, which have been rising at about 18% per year. From 2003 to 2009, for instance, “mining in the two sites has converted 6,600 hectares of primary tropical forest and wetlands to vast expanses of ponds and tailings,” the researchers report.” And “the new pattern of mining deforestation… is outpacing that of nearby settlement deforestation.” Meanwhile, the amount of mercury used by the miners could nearly double in 2011, to nearly 500 tons, further polluting water, air and land. The trends “bode poorly for the future of these ecosystems and communities,” they conclude.

Peru’s newly created Ministry of Environment is “actively struggling with the illegal mining issue,” they note, and recently announced a moratorium on new mining concessions. Peru has also been “recognized as having the potential to be a world leader in mercury stewardship.” But “major environmental improvements will not likely happen over the next few years,” they predict.

“Other developing countries endowed with gold deposits are likely experiencing similar environmental destruction in response to recent record high gold prices,” the note, adding that “the increasing availability of satellite imagery ought to evoke further studies linking economic variables with land use and cover changes on the ground.” David Malakoff | April 22, 2011

Source: Swenson, J., Carter, C., Domec, J., & Delgado, C. (2011). Gold Mining in the Peruvian Amazon: Global Prices, Deforestation, and Mercury Imports. PLoS ONE, 6 (4) DOI: 10.1371/journal.pone.0018875

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