Yarra Valley residents have been left baffled after the water in a creek turned bright lime green overnight.
"This is at Old Joes Creek basin in Boronia and doesn't look good at all," a concerned local posted in a community Facebook group on Tuesday with a picture of the unusually-coloured waterway in Boronia.
Members of the group responded with their best efforts to identify the cause.
"Looks like blue green algae," one person suggested.
"Doesn’t look very nice, hope no one is dumping chemicals!" one concerned member wrote.
"Looks like radiator coolant," a few people suggested.
Others in the group thought the image may have been edited.
"Is this real?" one person asked.
"Whatever it is, it needs taken care of, ASAP," a user commented.
Yahoo News Australia spoke with Melbourne Water, who confirmed they had attended the creek on Tuesday to asses the situation.
“Crews immediately attended the site and the substance was quickly removed from the impacted waterway,” Melbourne’s Regional Services Manager John Woodland (South East) said in a statement.
“It’s believed the substance was fluorescein, a dye commonly used by plumbers and contractors to trace and identify underground pipes. It’s non-toxic and not harmful to animals,” he explained.
Mr Woodland urged local residents to follow up with any additional information about the green creek.
“Should any member of the community have additional information on the spill in Old Joes Creek, we urge them to call the EPA’s 24-hour hotline 1300 372 842.”
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