In this February 3, 2017 photo, the Avila family fishes on the Coata River, which flows into Lake Titicaca, in the Puno region of Peru. Untreated sewage water drains from two dozen nearby cities, and illegal gold mines high in the Andes dump up to 15 tons of mercury a year into the river leading to the lake. (Photo by Rodrigo Abd/AP Photo)
