Mine ponds amplify mercury risks in Peru’s Amazon

The proliferation of pits and ponds created in recent years by miners digging for gold in Peru’s Amazon has altered the landscape and amplified the risk of mercury poisoning, a new study shows. In some watersheds, there’s been a 670% increase in land area covered by abandoned mining pits that have filled in with water. Low-oxygen conditions in these ponds accelerate the conversion of submerged mercury, a leftover from the mining, into highly toxic methylmercury.