Mar 06, 2017: A river in Spain has turned a bright green colour, forcing authorities to reassure residents the waters had not been contaminated.
The extraordinarily hue evoked memories of the way the Chicago River in the USA is deliberately turbed green every year for St Patrick’s Day .
The river began to change colour at its source in Andorra before spreading downstream to to the Catalonia region of Spain on Thursday.
Seu d’Urgell mayor Albert Batalla said the colouring was “entirely harmless, non-toxic and biodegradable” and had been intentional.
It was used, he said, as part of an investigation at the Arinsal water bottling plant.
"It is a harmless, non-toxic and bio-degradable dye that has been used for water research," he said.
The plant was linked to a gastroenteritis bug that made thousands sick last year.
The Andorran Ministry of Health said the harmless dye was used to help identify the source of possible contamination and would have no environmental impact.
"It is an action that has no impact beyond the visual," the government said.
It added the substance was harmless to both people and the natural environment and would dissolve within a few hours.