Mystery over why 'hidden gem' Humpybong Creek at Moreton Bay, Queensland suddenly turned electric blue - and locals are worried

Worried residents living near a creek locals describe as a 'hidden gem' were shocked after they discovered that the water had mysteriously turned a shade of bright electric blue. 

A member of the public noticed the water in Humpybong Creek at Moreton Bay in Brisbane's north had turned aqua blue on Monday morning. 

Officials from Queensland Fire Department (QFD) were alerted before three fire crews attended the scene following reports of a possible chemical spill. 

Fire crews determined that around five square metres had initially been affected by the unusual colour change. 

A QFD spokesman told Daily Mail Australia that scientists conducted tests and found that the substance was not poisonous. 

A Moreton Bay Council spokeswoman told Daily Mail they are investigating the unknown blue substance. 

'There has been little dispersion and the spill remains localised. There is no indication of any current impact on wildlife,,' the spokeswoman said. 

The spokeswoman said council officers have taken samples for assessment.  

'These tests will not be able to identify the exact substance, however the test will indicate if there is any presence of significant pollutants such as any increase in heavy metals,' the spokeswoman said. 

The type of substance is not known and it is unclear how it entered the water. 

Testing to determine what caused the water to so drastically change colour could take up to seven days. 

Officers have inspected the stormwater system within a 400m radius of the impacted area to determine where the substance came from. 

A Department of Environment, Science and Innovation (DESI) spokeswoman said DESI is aware of the contaminated water. 

The spokeswoman there is no indication of any environmental harm.

Locals expressed their anger on social media over the bizarre sight and said it could impact animals living in the area. 

'Heartbreaking for the wildlife,' one person wrote. 

'I hope whoever is responsible is held accountable,' another local wrote. 

But others thought the bright colour made the creek look better. 

'Looks amazing,' one person said. 

The water could be removed from the creek by pumping out the contaminated liquid before it is disposed of properly. 

Experts are also baffled by the strange discolouration. 

Head of Civil Engineering at the University of Sydney, Professor Stuart Khan, said the type of substance will be determined by conducting a chemical analysis. 

'It does look like copper contamination, which would be very easy to test for and confirm, 'Prof Khan told Yahoo.

Prof Khan, who is also a water expert, said copper has been used as a chemical in ponds to kill algae. 

He said a significant amount of the mineral may have been used if this was the case. 

The creek is an important catchment that transports untreated storm water from several residential and urban areas.