The Marañón River is under threat from an estimated 20 hydroelectric megadams (exact number remains undetermined, due to “muddled policy and lack of transparency in government”). Parties responsible for these developments are the Peruvian Government and large multinational companies. The Brazilian infrastructure giant Oderbrecht is behind several of these projects including one of the most contentious, Chadin II; this company is currently facing corruption charges for its involvement in the Petrobras scandal and links to the destructive Belo Monte dam in Brazil.

Oil extraction in the Peruvian Amazon has been the cause of many social and environmental issues since it begun half a century ago. In recent years pipelines and ageing infrastructure are failing with increasing regularity; causing enormous environmental damage and health issues for indigenous Awajún communities living nearby. Many oil spills have made their way into tributaries which flow to the Marañon River and inevitably into the greater Amazon.

There are many mining operations scattered throughout the Andes that leech pollution into tributaries which find their way to the Marañón River. Some of these outflows go unmonitored, with no-one to enforce environmental legislation. New mines are continually being proposed within this enormous watershed, while other mines will begin to reach the end of their lifecycle and become defunct, resulting in more environmental and social issues.

Small scale ‘artesenal mining’ can also create environmental issues. Mercury can be used in large quantities and discarded directly into the river. This issue will be compounded if dams are built and mercury is trapped in low oxygen environments.