The State Government has ordered an investigation into a malfunction at the North Pine water treatment plant which resulted in 20 times the regulated level of fluoride being added to household water supplies north of Brisbane.
Premier Anna Bligh this afternoon appeared alongside Chief Health officer Jeannette Young and SEQWater spokesman Jim Pruss to assure the community there was an extremely minimal health risk as a result of the error, which occurred two weeks ago.
The water treatment plant had been shut down for maintenance but fluoride continued to be added to the system, resulting in a higher concentration of being added to the water supply when the treatment system returned to operation a short time later.
Ms Bligh said she had been advised up to 30 milligrams of fluoride per litre had been detected in a sample of water taken from the North Pine plant on April 29, well above the regulated maximum concentration of 1.5 milligrams per litre.
It is understood about 4000 households, including parts of Brendale and Warner, would potentially have received water to their pipes with elevated fluoride levels between 9am and 12pm on May 1.
Ms Young said any adverse health affects were “very unlikely”.
She said someone who drank a large amount of water in the affected areas during the three-hour period may have experienced “very mild gastroenteritis”, but she was not aware of any such cases in the past two weeks.
There would be no long-term health consequences, Ms Young said.
Ms Bligh defended not telling the public sooner, saying SEQWater was not aware of the problem until the results of the April 29 water sample came back on Tuesday.
The Premier, who continues to back the addition of fluoride to South-East Queensland water supplies, said she was personally informed of the result last night.
The malfunction, in which dosage units continued to add fluoride in the water treatment plant even though it was shut down for three days, was “completely unprecedented” in Australia, she said.
“I think it’s important to understand this is an extremely unusual event,” she told reporters in Brisbane.
Authorities have shut down the fluoride dosage units at the North Pine water treatment plant until an investigation is completed.
Mr Pruss said fluoride dosage units would be manually shut down at other SEQ plants whenever maintenance was required to prevent a repeat incident.