During routine monitoring at 1pm, Tuesday 3 April, elevated fluoride levels were detected in the Longburn community water supply. Laboratory testing confirmed the elevated levels at 8.7mg/l, which is above the target level of 0.7–1.0mg/l.
On notification, the dosing system was immediately switched off. Samples were taken, followed by a complete flushing of the entire Longburn network.
An investigation has identified that the incorrect dosing started on Thursday 29 March following an unauthorised change made by a contractor, and continued over the Easter holiday period. There are not expected to be any health issues related to the incident.
By 5pm on Tuesday 3 April, fluoride levels in the water supply had dropped to 0.2mg/l. Samples on 28 March and 4 April tested by a certified laboratory show the fluoride level to be well within the target level.
“We consider this a serious matter and having confirmed the cause of the error, we have taken steps to ensure this doesn’t happen again,” says Robert Van Bentum, PNCC Water and Waste Services Manager.
MidCentral Public Health Service advises the levels found in the water supply were well below any short-term exposure guidelines, therefore no acute health effects would be expected from this incident. There is also expected to be no risk of any long-term impacts given the very short period of exposure.
Dr Rob Weir, Medical Officer of Health said: “In view of the very short duration of the incident, MidCentral Public Health Service also considers there is an extremely low risk of any cumulative effects from the elevated fluoride levels.”
Anyone concerned about their health is advised to see their GP or ring Healthline on 0800 611 116.