Gold mining shifts course of Peruvian river, ‘will destroy’ ecosystems

Sediment isn’t the only thing gold mining releases into water. Mercury is often used to collect ore, as it attracts tiny bits of gold into a larger conglomerate. Miners then burn off the mercury, where it escapes into the air and water. Mercury magnifies up the food chain, and is found in high levels in predatory fish in several places in South America that are host to gold mines. In Madre de Dios, the Peruvian department where the Malinowski and Tambopata rivers are located, a 2013 study found several fish species contained levels of mercury that were in some cases twice as high as the U.S. Environmental Protection Agency safety threshold. The heavy metal acts as a neurotoxin if consumed at high enough levels, impairing cognitive function and causing birth defects.
https://news.mongabay.com/2016/05/gold-mining-shifts-course-peruvian-river-will-destroy-ecosystems/