The government has been criticised for apparent inaction as evidence mounts that mercury contamination is causing illness in fishing communities

Outside a small brick house shared by four families, Daniela Prada, who is heavily pregnant, gathers guava leaves to make a tea for her two-year-old son.

“My baby gets sick a lot,” she says, boiling a pot of water in her outdoor kitchen. “He always has diarrhoea and last night he had a fever. Most of the time I give him natural medicine.”

In an identical house nearby, town leader Oscar Lurici says fevers are a part of life in Eyiyo Quibo village on the Beni River in northern Bolivia. People of all ages suffer from debilitating head and body aches, bouts of vomiting and diarrhoea, memory loss and tiredness. Some children show signs of cognitive development delays.