Illegal gold mining muddied the river, spread mercury and disorganized communities, whose residents are looking for answers to children's developmental disorders.
Like a childhood ritual, the Munduruku children have two encounters with the Kabitutu River every day.
"Wait a while and you'll see them all in the river. Everything turns black," says teacher Misael Munduruku, 54, in reference to the color of the boys' and girls' hair.
The clock strikes 12, the start of a hot, muggy September afternoon in the Amazon — the heat and dryness of the rivers, in this cycle of the forest's ebb and flow, are increasingly extreme. Hundreds of children emerge together from the heart of Katõ, the largest village in the part of the TI (Indigenous Land) Munduruku that revolves around the Kabitutu River.
The calmness with which they make their way to the village gate contrasts with the fast pace of their games in the riverbed. Bathing in the Kabitutu, a river with muddy water, muddy and pasty in appearance, as a result of the land turned over by gold mines in the territory, is noisy and euphoric. The ritual is repeated from 6pm. And so it is every day.