Why has this river in Spain turned a luminous green?

River in the Pyrenees has an alarming new hue

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A river in Spain turned an extremely bright green on Thursday morning, leaving local residents somewhat alarmed.

The Valira River in north east Spain flows down the Pyrennees Mountains from the tiny nation of Andorra into Spain, where it empties into the Segre River near Seu d'Urgell.

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See also: Find out why this Spanish river flows with red water


Albert Batalla, the mayor of Seu d'Urgell, was quick to reassure residents that the river had been intentionally dyed green with an "entirely harmless, non-toxic, and biodegradable" substance.

The USA Today reports that the dye was added as part of an investigation at a water bottling plant to identify the source of a possible contamination.


The Local reports that the water plant was last year traced to be the source of a gastroenteritis bug that affected thousands of people across Catalonia who drank contaminated water from office water coolers.

Andorra's Ministry of Health confirmed that the harmless dye had been used to help identify the source of possible contamination and would have no environmental impact. But it made for some great pictures.

Best river cruise lines (according to Cruise Critic)

Best river cruise lines (according to Cruise Critic)