They're Going Door-To-Door In The Amazon To See Why People Get Sick

Those questions are bedeviling researchers from Duke University, who've been studying gold mining in the region. Illegal mining has exploded in the area in the last decade. And the people living downriver have a variety of medical issues, from malaria to anemia to high blood pressure.
The researchers have documented that mercury used in illegal gold mining ends up hundreds of miles downstream from the mines. And it eventually ends up in fish — a major local source of protein.
http://www.npr.org/sections/goatsandsoda/2015/05/19/401970884/theyre-going-door-to-door-in-the-amazon-to-see-why-people-get-sick