The explosion of mining in the mid-section of the Tapajós River is most likely the cause of the change in water color in Alter do Chão, one of the most desired beaches in Brazil, according to an analysis by MapBiomas.
Although the annual flooding of the Amazon River contributes to the change in color of the Tapajós River at the height of Alter do Chão, the cyclical and natural opacity at that season is not enough to explain the changes seen in Alter and other parts of the river this year.
You can clearly see the line of sediments moving down the tributaries taken over by the miners and advancing towards the Tapajós. By the time it reaches the city of Itaituba, the Brazilian capital of illegal gold, the river, once known as the ‘blue river’ becomes opaque, and this turbidity advances to the mouth of the river.
To get at the gold, prospectors dig up river bottoms with dredges and excavate huge ravines with wheel loaders. The destruction can extend for miles along the course of the river.
According to a survey by MapBiomas, the mining area in the Amazon has grown tenfold in the last three decades, and 2020 (the last year for which data is available) holds the record in this series.
The pandemic caused an explosion in the price of gold, which in 2020 reached US$ 2,000 a troy ounce (unit of sale of gold, equivalent to 31.1 grams) for the first time. This sparked a gold rush in the Amazon.