A stream winding through a populous area on the outskirts of Buenos Aires has turned crimson red in recent hours that has sparked fears of industrial chemical dumping.

The Sarandí Canal near Buenos Aires turned bright red, alarming residents and prompting an investigation into potential industrial pollution.

A stream south of the Argentine capital turned a freakish vermilion this week, prompting concerns about pollution. Officials said it could be the result of “some type of organic dye.”

A small river in greater Buenos Aires was dyed a deep and worrying shade of red on Thursday after what is thought to have been a leak of dye from a nearby factory.