Source: Radio New Zealand
The Southland Regional Council report said in some places the nitrate concentrations in groundwater exceeded the New Zealand drinking water standard of 11.3 mg/L. 123RF
A report has exposed increasing nitrate contamination in Southland’s groundwater, sparking a call from Greenpeace for a nitrate emergency to be declared in the region.
The Southland Regional Council report said approximately 15,000 Southlanders could be drinking water polluted by nitrates.
It pointed to the intensification of dairy farming as a key cause of growing nitrate levels.
The report said nitrate concentrations in groundwater frequently exceeded 3.5 mg/L and in some places exceeded the New Zealand drinking water standard of 11.3 mg/L.
More than half of Southland’s domestic drinking water supply wells were estimated to have nitrate concentrations above 3.5 mg/L.
The Ministry of Health considers the current maximum acceptable value (MAV) for nitrate appropriate, although some public health experts argue the drinking water limit is too high and potentially puts people at risk of pre-term birth and bowel cancer.
Greenpeace freshwater campaigner Will Appelbe said the findings were alarming.
“It’s made clear what many of us have known for quite some time, that nitrate contamination is a real crisis in Southland and the main cause of that contamination is the intensive dairy industry,” he said.
“At a bare minimum it’s time that Environment Southland declared a nitrate emergency. Environment Canterbury declared one last year for very good reason, it’s clear that Southland has a drinking water crisis on its hands and it’s a result of nitrate contamination.”
The report said the region’s dairy boom had coincided with a decline in water quality and the region’s groundwater was vulnerable to contamination.
Between 1990 and 2022, Southland’s dairy herd increased by 1668 percent from 38,000 to 668,000 cows.
Otago University research fellow Marnie Prickett said Southland needed to reduce its dairy herd, and she was also calling for an independent inquiry into the regional council’s land-use rules.
“Southlanders need Environment Southland to chart a really robust path out of this. It can’t be tinkering around the edges it has to be driving confidently forward about what they’re going to do,” she said.
The report said 44 percent of domestic supply wells (612) and 45 percent of registered public drinking-water supplies (18) were located within areas classified as having “high vulnerability to nitrate contamination”.
“here may be approximately 1,530 people on private supplies and 13,632 on public groundwater supplies at risk of exposure to high concentrations of nitrate in drinking water,” the report said.
A graph from the Nitrogen Contamination in Southland Groundwater 2026. Supplied
Environment Southland general manager science Karen Wilson said although the report did not present new data, it brought together a range of information to give an integrated view of groundwater quality, nitrate sources, and health risks.
“This science formed the basis of the Southland Water and Land Plan, which was accepted by the Environment Court. The plan was the first step in responding to Southland’s groundwater nitrate challenges,” she said.
Federated Farmers Southland president Jason Herrick said declaring a nitrate emergency would be an overreaction and unhelpful.
“Nitrates aren’t a new issue for Southlanders at all, and it’s not just dairy, as a society and as a people we’re all responsible for our challenges that we had. This is a long-standing challenge that the community have been aware of and working on for quite some time now,” he said.
The report said 71 percent of groundwater sites had shown increasing nitrate contamination over the past two decades.
Hotspots included Balfour/Waimea Plains, Wendonside Terrace, Five Rivers/Castlerock, Edendale, Knapdale, Mabel Bush/Woodlands, Central Plains/Waimatuku, and Otahu Flat.
Southland Regional Council freshwater principal scientist Ewen Rodway said the council was working to deal with the problem.
“We’re continuing to monitor groundwater quality across the region, identifying these high-risk areas and using those to focus efforts such as focusing farm plans, and working with catchment groups to reduce nitrogen losses in those vulnerable areas,” he said.
Rodway said a decision about declaring a nitrate emergency sat with councillors.
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand
