So called 'forever chemicals' can be harmful and can take many years to break down. Photo: 123rf
Australia and the United States are slashing the limits on toxic "forever chemicals" in drinking water to protect human health, but New Zealand is staying put.
Australia is moving to drop one of its key limits by almost 20 times - a move already made by the US.
Poly-fluorinated alkyl substances, or PFAS, are virtually indestructible, man-made fluorocarbons widely used in manufactured products.
The US Environmental Protection Agency said PFAS exposure over a long period of time "can cause cancer and other serious illnesses that decrease quality of life or result in death".
New Zealand has previously followed Australia's lead in setting standards or limits.
But while Australia is moving to match the US, and cut one key limit to just four parts per trillion (ppt), New Zealand remains at 70ppt.
For another limit, Australia is aiming for 200ppt, and the US has already dropped to just 4ppt - but New Zealand is staying at 560ppt, 140 times higher than America.
New Zealanders are comparatively less exposed to PFAS in the environment as less manufacturing with the substances is done here.
The national water regulator Taumata Arowai said it had no plans to drop limits.
"The authority does not automatically adopt overseas values without thorough review and adaptation to New Zealand conditions," it told RNZ.
Taumata Arowai set the current limits in 2022, shortly after the agency was established, following similar guidelines adopted around 2018 to align with Australia.
"There are currently no plans to change" the maximum acceptable values, it said.
The Ministry of Health gives the authority advice about PFAS, but has not done so over these moves overseas.
"We can confirm we have not provided any advice to the authority regarding the PFAS [maximum acceptable values] since USA Environmental Protection Agency published enforceable limits for some PFAS chemicals for the first time in April 2024 and the National Health and Medical Research Council in Australia released their consultation document on changes to their guideline values for PFAS chemicals in October," the ministry told RNZ on Friday.
An Auckland water treatment plant at Onehunga shut temporarily in 2022 after PFAS levels got too high, and now looks set to reopen only in 2027, under a $40m upgrade to remove the contaminants using granular-activated carbon filtration.
PFOS is a common type of PFAS: This is subject to Australia's move to cut its limit to 4ppt.
PFOA, another common type, is subject to Australia's move to cut it to 200ppt. The International Agency for Research on Cancer classifies PFOA as a carcinogen.
The US Environmental Protection Agency, when it slashed the limits as part of its first-ever national, legally enforceable drinking water standard in April, said this was based on "the best available science".
"Fewer people will get cancer or liver disease, pregnant women will have reduced risks, and more and children and infants will be stronger and grow healthier," the EPA said.
The official health advice in New Zealand, however, says the health effects of PFAS are "uncertain".
This is based on information first put out in 2018, soon after the Defence Force first revealed PFAS contamination around some of its bases, and updated last year.
The Ministry of Health took the lead on health matters, Taumata Arowai's head of operations Steve Taylor said.
"We work closely with the Ministry of Health and continue to monitor developments internationally in regard to PFAS."
Since 2020, international studies into PFAS have multiplied into the tens of thousands.
RNZ asked the Ministry of Health how it was taking those many new studies into account. It repeated what Taumata Arowai had said and added: "Any advice we do provide on [maximum acceptable values] takes in account both international evidence and to what extent that evidence is applicable in a New Zealand context."
The first study of impacts on a global scale earlier this year found much of the global source water exceeds PFAS safe drinking limits.
While other countries have been moving to regulate batches of the chemicals, New Zealand still regulates just two forms of PFAS. In total, there are more than 14,000 kinds.
Taumata Arowai said it was "not unusual" for drinking water standards to vary from country to country. This was "due to different risk assessment methodologies, calculations, the choice of health endpoints used, and legislative frameworks", it said.
Europe already has 100ppt limit on a "sum" of 20 types, and has proposed to drop this to just 4.4ppt for the sum of 24 types of PFAS in groundwater.
The World Health Organization said countries should " strive to achieve concentrations in drinking water that are as low as reasonably practical". It has guideline limits of 100ppt for both PFOS and PFOA.
Taumata Arowai said the differences in approaches "can in part be explained by the differences in use and prevalence".
Tests of drinking water in 20 New Zealand suburbs recently found PFAS in very low levels, at under one part per trillion.
Testing of 130 groundwater wells in 2023 also found low levels of PFAS, but called for more investigations, though authorities rejected that call, saying, "The monitoring results don't show the need for further investigation."
Globally, 2023 was a "landmark year" for combating PFAS, a review by New Zealand scientists said. The changes in the US, for example, "could impact all facets of water production and wastewater management", it said.
The US EPA has estimated the annual compliance costs at $2.5 billion, but that savings in health costs from fewer cancers, heart attacks and strokes, and reduced birth complications would match that.
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