A waterway in a suburb of Argentina’s capital Buenos Aires turned bright red on Thursday, alarming locals.

The Sarandí Canal flows through residential neighbourhoods and industrial areas before reaching an estuary, the Rio de la Plata, which borders an ecological reserve.

Local media reports suggested the colour may have been caused by the dumping of textile dye, or by chemical waste from a nearby depot.

Authorities have taken samples to determine the source of the contamination.

Read more: Argentina canal turns bright red