'A real warning sign': Mystery surrounds 'very strange' water at Sydney park

Bright green-coloured water spewing from a stormwater channel in Sydney has left residents scratching their heads.

A woman filmed the “very strange” looking water in Rushcutters Bay Park near the city’s centre and posted the footage to Facebook last Saturday.

“What is this green chemical coming from the sewage system at Rushcutters park?” she wrote alongside the clip.

The green-coloured water seen at Sydney's Rushcutters Bay Park.
The bright green water seen at Rushcutters Bay Park last Saturday. Source: Facebook

Footage shows groups of people looking at the bright green water with quizzical expressions.

Some Facebook viewers joked the liquid was Mountain Dew or Midori liquor.

Many others insisted it was fluorescein, which is used to check for leaks in stormwater and sewer systems.

“It’s a non-toxic fluorescein dye. It is used by plumbers and water authorities to trace leaks,” one man wrote.

A woman said she had also seen the green water, calling it “very strange”.

A spokesperson for Woollahra Municipal Council told Yahoo News Australia the area seen in the footage was a stormwater channel owned and operated by Sydney Water.

Sydney Water told Yahoo News Australia it was aware of the bright green water, but said it was “a matter for City of Sydney Council”.

A City of Sydney spokesperson told Yahoo News Australia “stormwater outlets within the park are managed by Sydney Water”.

“The City’s stormwater network is one water source that feeds into the Sydney Water culverts,” the spokesperson said.

“Non-toxic tracing dyes can be used by private contractors to check the flow of pipes upstream. The City of Sydney does not use this dye.”

‘Could be highly toxic’

There is something very wrong with the quality of the water in the video clip, Dr Ian Wright, a senior lecturer at Western Sydney University’s School of Science, told Yahoo News Australia on Friday.

The colour could be caused by fluorescein, but could also be a “rip-roaring algae bloom”, he said.

“That colour is a real warning sign,” Dr Wright, who used to work for Sydney Water, said.

“If it’s algae, that’s a really bad bloom.”

Blue-green algae is highly toxic and can cause live damage to people and animals, Dr Wright explained.

“It can actually kill. It needs to be checked out,” he added.s

NSW has recently seen heavy rainfall and warm temperatures, meaning an algae bloom is possible, he said.

Any NSW resident who sees what they believe is pollution in their community is urged to call the EPA hotline on 131 555.

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