BRASILIA, (Reuters) – The browning of one of Brazil’s largest clearwater rivers, the Tapajos, is almost certainly due to the mud and sentiments churned up by increasing illegal gold mining, federal prosecutors and environmental activists said on Monday.
Once called the “Blue River” because of its pristine condition and clear waters, the Tapajos has drawn a rush of gold miners since 2019 as world prices soared and environmental enforcement faltered under Brazil’s far-right government.
The illegal miners use mechanical shovels to knock down trees and dig pits, and dredging barges that vacuum river beds, sucking up mud and water as they search for gold.
Chocolate-colored water can be seen for hundreds of kilometers in aerial photographs, flowing out of tributaries and down the Tapajos to its confluence with the Amazon river.
The silt in the water has kept bathers away from the white sandbanks of Alter do Chao, a popular resort in the lower Tapajos, a tributary that flows 1,300 miles (2,100 km) to the Amazon.
Prosecutor Gustavo Alcantara said his office has estimated that seven million tonnes of sediment are dumped into the Tapajos each year by the illegal miners. He urged federal and state environmental agencies to investigate how the gold mining is polluting the river.
Satellite data shows that the increasing change in color of the Tapajos river coincides with the rapid increase in gold mining activity in the region, according to MapBiomas, a nongovernmental organization that tracks land use and deforestation in Brazil.
“It is reasonable to assume that illegal mining has been one of the main causes of the murky waters, because it is all done on tributaries of the river and the sediment flows into the Tapajos,” said MapBiomas geographer Cesar Diniz.
“It’s a fact: The mining has contributed to the muddying of the Tapajos in recent years,” he said.
