Fluoride levels in Longburn water supply
11 April 2018
Palmerston North City Council (PNCC) and Public Health Services of MidCentral Health (PHS) advise of a recent incident
relating to the fluoride dosing system at Longburn.
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 8.7 mg/L, which is above the target level of 0.7 – 1.0
mg/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 had 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 0.2 mg/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.
Health Impacts
MidCentral Public Health Services 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 Services also considers there is an extremely low risk of any cumulative effects from the elevated fluoride
levels.”
If anyone is concerned about their health, they are advised to see their GP or ring Healthline on 0800 611 116.
Ends