Description : An aerial view of Mavaca river section, near a Yanomami community. Mavaca River is one of the many affluent of the Orinoco River in the region. In spite of the brown colour they always had, they were clean until mining and other uncontrolled industries arrived. Mining industries use highly poisonous mercury that goes directly into the rivers and it is almost impossible to clean up. High Orinoco State, Venezuela. July 22, 2007. Part of the photo story, 'Yanomamis: The Spirit of Amazonia', by Diego Martinez.