Illegal mining in Latin America

The environmental impact can be devastating, too. Dredging can cause rivers to silt up, for example. Last year a research team from the Carnegie Institution for Science carried out an assessment of Madre de Dios, using a combination of satellites, aircraft and researchers in the field. “We were shocked,” says Greg Asner, the project leader. “We’re all used to deforestation as a serious issue. But this is the complete removal of the ecosystem down to the soil layer. It almost looks like a moonscape.”
The water supply has also been affected. Thirty to forty tonnes of mercury are pumped into rivers in the region each year. Unsurprisingly, it has worked its way through the food chain. By analysing hair samples, another Carnegie study found that 78% of people in Madre de Dios had three times the usual concentration of mercury in their bodies. Some were more than 27 times over the international limit.
http://www.economist.com/blogs/americasview/2014/09/illegal-mining-latin-america