There are fears of water contamination after a bridge collapsed in northern Brazil at the weekend, sending lorries carrying thousands of litres of pesticides and sulphuric acid into the river below.
Four people are known to have died, and more than 10 are missing after the central span of the bridge linking Tocantins and Maranhão states gave way on Sunday afternoon.
It is not clear if or how much the chemicals have leaked from their containers, but diving operations in the river have been halted while the situation is assessed.
Dramatic video filmed by a local councillor who went to the bridge to draw attention to cracks in it showed the start of the collapse.