Greenpeace says recent research into the link between adverse birth outcomes and nitrate contamination of drinking water should compel the government to take immediate action to cut sources of nitrate pollution, including synthetic nitrogen fertiliser.

Greenpeace senior campaigner Steve Abel says the new research adds to the body of evidence that shows nitrate contamination of drinking water from intensive dairying is a seeping health threat, affecting babies in utero and associated with cancer in adults.

"We already know that synthetic nitrogen fertiliser is killing our rivers and intensifying climate damage. It's increasingly clear that the favourite chemical of intensive dairying is making people sick," says Abel.

University of Otago researchers have published a blog post on the UO Public Health Expert Blog, reviewing recent research into adverse birth outcomes caused by nitrate contamination, and raising the alarm about high nitrate concentrations in drinking water in parts of New Zealand.

The blog quotes authors of a 2021 US study which found nitrate-nitrogen levels in drinking water above 5 mg/L increased the odds of a preterm birth (20-31 weeks) by 47%, while exposure above 10 mg/L increased the odds of a preterm birth 2.5 times.

New Zealand’s current health limit for nitrate-nitrogen is 11.3mg/L, based on the limit necessary to avoid blue baby syndrome. This limit is more than double the amount now strongly linked to preterm births, and thirteen times that associated with bowel cancer in an international study (0.87mg/L).

Abel says this research is disturbing news for expectant parents.

"No pregnant person should have to fear that water from their tap might be harming their baby," says Abel.

The research adds to the growing public concern about drinking water safety, which has seen hundreds of people attending water testing events across Canterbury. Greenpeace is running free drop-in water testing for households on bore water in Canterbury this weekend, in association with the Federation of Freshwater Anglers.

The University of Otago researchers point to intensive agriculture as the culprit, saying that "nitrate is one of the most common drinking water contaminants in NZ, largely driven by agricultural activity (nitrogen fertiliser application and livestock urine). Nitrate leached into water from dairy farming has increased substantially since 1990."

One of the researchers, Dr Michael Baker, previously stated that "our water is getting a lot more contaminated because of our absolute love-affair with nitrate fertilisers."

The culprit is "undeniable,'' says Abel.

"It’s obvious. The areas of New Zealand with high levels of nitrate contamination in water are the areas with intensive dairying - like Canterbury, Southland and Waikato. We know what is causing this spike in nitrate contamination in our drinking water: too much synthetic nitrogen fertiliser, too many cows, and too much cow urine," says Abel.

The University of Otago researchers blog post says the new studies ‘reinforce the need for a precautionary approach to setting lower nitrate limits in drinking water for human and ecological health.’

Greenpeace is calling on the Government to lower the limit on nitrate allowed in drinking water from 11.3mg/L to 0.87mg/L in line with international research, and act on it by phasing out the use of synthetic nitrogen fertiliser.

"Synthetic fertiliser is a key driver of intensive dairying, and the nitrate pollution flowing from land crammed with too many cows is turning our drinking water toxic," says Abel.

"Both central and local government have failed in their regulatory obligation to protect the health of our people and environment. They need to act now by cutting synthetic nitrogen fertiliser, lowering stocking rates and shifting to regenerative organic farming so we can all live in a country where rivers run clear and our tap water is safe to drink."

Greenpeace water testing days:

10am - 2pm Saturday 29th May, Dunsandel Community Centre

9am - 1pm Sunday 30th May, Woodend Community Centre

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