Source: Radio New Zealand
New Zealand’s current legal limit for nitrates in drinking water is 11.3 mg/L. HENDRIK SCHMIDT
Greenpeace is calling on the government to drastically cut the legal limit of nitrates in drinking water as the Danish government moves to drop its legal limit by almost 90 percent.
The Danish government plans to lower its limit to just over one milligram of nitrate-nitrogen per litre (mg/L) of drinking water, a steep drop from its current limit of 11.3mg/L.
New Zealand’s current legal limit for nitrates in drinking water is 11.3 mg/L, but there was growing evidence of health impacts at levels as low as 1mg/L.
An expert group commissioned by the Danish government in 2024 to examine nitrate levels reported back late last year and recommended reducing the nitrate contamination limit to 1.3 mg/L nitrate-nitrogen.
Danish state broadcaster DR reported Environment Minister Magnus Heunicke had received the group’s recommendations and has committed to adopting them.
“It is an urgent matter. When there is such a clear conclusion from our independent experts, of course we have to react to it. There is no other choice,” DR reported the minister as saying.
Greenpeace spokesperson Will Appelbe said the organisation had sent an open letter to Local Government Minister Simon Watts and Health Minister Simeon Brown, urging them to follow the Danish government’s lead.
RNZ approached Watts and Brown for comment.
“The Danish government aren’t operating off a secret playbook or anything, they don’t know anything we don’t know. They’re just following the scientific evidence and choosing to prioritise people’s health. Meanwhile, our government is burying its head in the sand,” Appelbe said.
The panel’s report quoted 2023 University of Copenhagen research, which found lowering nitrate contamination would save 2.2 billion Kroner ($580m NZD) by preventing approximately 127 cases of bowel cancer per year linked to the current nitrate levels.
Fertiliser use was the primary source of nitrate contamination, the report said.
Appelbe said there was overwhelming evidence that the same was true in New Zealand.
“Anyone suggesting otherwise isn’t being particularly honest about what the science is telling us,” he said.
“We need to urgently take measures to reduce that risk. That means reducing cow numbers and reducing synthetic nitrogen fertiliser.”
Appelbe said the government was more concerned with protecting dairy industry profits than human health and he called for reductions in the size of the dairy herd, an end to ongoing dairy expansions and limits to the use of nitrate fertiliser.
“The evidence is clear nitrate contamination is a risk to human health – there’s a growing body of evidence that says so – and the government needs to take action to lower the nitrate limit so people can rely on the drinking water they need.”
Greenpeace spokesperson Will Appelbe said nitrate contamination was a risk to human health. RNZ / Nate McKinnon
Rural communities were disproportionately affected and faced considerable costs installing filters to make their water drinkable, he said.
“We need, as a country, to have a grown-up conversation about nitrate contamination in drinking water – the evidence is pretty overwhelming on what’s causing it and there’s a growing body of evidence that links risks to human health.”
Appelbe said the current limit of 11.3mg/L is based on World Health Organisation guidance from the 1960s to avoid Blue Baby Syndrome, an acute illness that could affect babies.
A 2025 GNS Science research paper estimated there could be more than 21,200 people drinking water above the legal limit of 11.3 mg/L and 101,000 people drinking water above half that (5.65mg/L) across rural New Zealand.
The authors found Waikato, Canterbury and Southland were disproportionately affected by elevated levels of nitrate
Public health specialists had long advocated to lower the nitrate limit, primarily based on international research linking low levels of nitrate (5mg/L) with pre-term birth and colorectal cancer (0.87mg/L).
New research from Australia’s Edith Cowan University and the Danish Cancer Research Institute found a link to early-onset dementia as low as 1.2mg/L with nitrates from processed meat and drinking water posing a higher risk, while nitrates from vegetables were associated with a lower risk.
The Canterbury Regional Council declared a nitrate emergency last year and there have been calls for Southland to do the same since the release of a regional council report mapping nitrate pollution across the region.
Canterbury’s dairy herd has increased by about 1000 percent since 1990 to well over a million cows.
Between 1990 and 2022, Southland’s dairy herd increased by 1668 percent from 38,000 to 668,000 cows.
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand
