The latest failure is not the first time Wellington has unknowingly gone years without effective levels of fluoride.
Data on fluoride compliance released by Wellington Water showed water has often dropped below recommended levels since 2016 – on three occasions not meeting the recommended level for more than a year.
Dr Rob Beaglehole from the New Zealand Dental Association said those long stretches without optimal fluoridation were “disheartening” and would “absolutely” have had an impact on oral health.
The optimal range for fluoridation is between 0.7 and 1 milligrams per litre, which provides the “best protection”, Beaglehole said. If fluoride levels are outside that range, residents are not receiving the highest protection.
Regional Public Health – the health regulator up until 1 September 2020 – was aware of the inconsistencies in fluoride levels since 2016, said medical officer of health Stephen Palmer.
They were also aware of Wellington water’s “conservative” approach to fluoride dosing. “There are obvious health risks with over-dosing the supply, and our priority as the regulator at the time was to ensure that over-dosing did not occur,” Palmer said.
The inconsistent fluoridation meant that out of the four water treatment plants, only the Waterloo plant managed to hit the fluoride target at least 50% of the time. The other plants fluoridated on a patchy basis, with long stretches where fluoride never reached the recommended levels.
“Since July 2016, on average, the optimal range of fluoridation was met about 50% of the time at Waterloo, 30% of the time at Wainuiomata (although this has improved since July 2021), and less than 20% of the time at Te M?rua and Gear Island,” said Doug Martin’s independent report on the failure to fluoridate.
The numbers behind Martin’s finding of “low and inconsistent dosing” include entire years when plants did not fluoridate water at recommended levels.
Gear Island, fluoridating water for Wellington’s eastern, southern, and central suburbs, had the longest stretch without optimum fluoridation. The plant did not have enough fluoride in its water for more than two years, between May 2017 and September 2019.
“This is worse than first thought,” said councillor Fleur Fitzsimons, who represents Wellington’s Paekawakawa Southern ward.
“Months without fluoride is a problem but this is years of failing to fluoridate drinking water. Young children have suffered as a result of this basic failure.”
The other plant which stopped fluoridating in 2021, Te M?rua, also had a patchy record of fluoridation. There was insufficient fluoride in its water for almost a year, between December 2018 and December 2019.
Te Marua’s failure to fluoridate goes back further than the plant being turned off in May 2021. Fluoridation has been below effective levels since 11 December 2021, four months before Wellington Water said it had stopped fluoridating.
There were problems at Wainuiomata too, one of the two plants which continues to fluoridate water. From January 2019 until May 2021, the water did not meet its fluoridation targets.
Beaglehole was hopeful that moving forward, Wellington Water will be more consistent in meetings its fluoridation targets. But he cautioned that preventing tooth decay is not only about “turning the fluoride tap on – we also need to turn the sugar tap off”.
CORRECTION: A previous version of the story said Regional Public Health acted as regulator until 1 September 2021. That was incorrect – they stopped acting as regulator on 1 September 2020. (Amended July 23 2022 at 12.31pm.)
*Original article online at https://www.stuff.co.nz/dominion-post/news/wellington/129356022/failure-not-the-first-time-wellington-has-gone-a-year-without-fluoride
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