In short:
Brazilian authorities are assessing the risks of water contamination after a bridge collapsed underneath trucks carrying sulphuric acid.
Four people have died and more than 10 people are still missing when the bridge gave way.
What's next?
The agency said it was monitoring the risk of contamination and water samples would be collected from the river.
Brazilian authorities are assessing the risks of water contamination after trucks carrying sulphuric acid and agricultural pesticides plunged into a river in a deadly bridge collapse.
The central span of the 533-metre bridge, which links the cities of Estreito in Maranhão and Aguiarnopolis in Tocantins, gave way as vehicles were crossing above the Tocantins River on Sunday.
A video showed Aguiarnopolis city councilman Elias Junior making a recording asking authorities to fix problems with the bridge, which he said could no longer handle the heavy trucks passing over it.
As he pointed to a large crack on the shoulder of the bridge, a portion of the structure started collapsing in front of him, with some motorists managing to stop their vehicles in time.
A large truck was also seen on the bridge in the video before the camera turned to follow Mr Junior running towards the river.
The Maranhão and Tocantins authorities have confirmed four people have died and more than 10 people are still missing.
Rescue divers halted their efforts after finding that trucks transporting sulphuric acid had plunged into the river.
Four people died and 10 others are still missing after the bridge collapsed. (Reuters: Mauricio Marinho)
"We are waiting for specific institutions to collect and analyse the water so that we, along with 25 divers, can dive to retrieve the victims that are on the bed of the Tocantins River," Colonel Magnum Coelho from the Maranhão fire brigade said.
According to Brazilian water regulator ANA, three trucks carrying 76 metric tons of sulphuric acid and about 25,000 litres of agricultural pesticides plunged into the river.
The agency said it was monitoring the risk of contamination and water samples would be collected from the river.
It was not immediately clear if the chemicals were leaking, and if so by how much.
"Even though we still don't have final analysis results on pollution, the Environment Ministry identified that the water pH was normal," Maranhão state Governor Carlos Brandao said.
Authorities have warned cities that could be affected by the incident to avoid collecting water from the river.
Authorities say three trucks carrying sulphuric acid and agricultural pesticides plunged into the river. (Reuters: Mauricio Marinho)
