Greenpeace is calling on Environment Canterbury to be upfront about health risks of nitrate contamination, following ECan’s release of new data that shows nitrate contamination in drinking water is rising.

ECan has released the results of its annual groundwater quality survey for 2020. 322 wells were tested, with the highest nitrate reading of 22mg/L being almost double the current health limit for drinking water (11.3mg/L).

Greenpeace says ECan’s data is consistent with Greenpeace’s own results from free nitrate water testing days across Canterbury, with both datasets showing concerningly high and worsening levels of nitrate.

Greenpeace senior campaigner Steve Abel says ECan’s comments on the data do not tell the whole story about the risks of nitrate contamination.

"The current message from ECan is that if your water is anywhere under that extremely high contamination rate of 11.3mg per litre of nitrate, then it’s safe to drink. That denies the emerging science showing adverse health effects well below that limit," says Abel.

A major 2018 Danish study has shown a significantly increased risk of bowel cancer at just 0.87mg/L of nitrate contamination in drinking water.

At 5mg/L, nitrate contamination in drinking water has been shown to increase risk of premature births by half, prompting the NZ College of Midwives to call on the Government to lower the current 11.3mg/L limit.

"This emerging research is telling us that there’s a health risk with nitrate contamination in water at much lower levels than previously thought. With nitrate contamination steadily worsening across Canterbury, ECan needs to be upfront with communities about the chronic health risks of nitrate contamination in drinking water," says Abel.

Twenty wells tested by ECan were above the 11.3mg/L limit, with 13 of those in the Ashburton area. Greenpeace conducted free water testing in Ashburton on the 10th of July, testing 101 samples, with 10 being over the current health limit and around 90% over the nitrate concentration linked to bowel cancer.

Greenpeace has now tested over 450 water samples across the Canterbury region. Abel says local communities are clearly concerned about nitrate levels in their water.

"The fact that we’ve had such demand for these free testing days, and the tone of the conversations that we’re having with Cantabrians, show that people are taking the nitrate risk to their health seriously," says Abel.

Abel says a near 7-fold increase in synthetic nitrogen fertiliser use associated with Canterbury’s boom in intensive dairying over the past few decades is primarily to blame. Cow urine and synthetic nitrogen fertiliser are the main culprits in the worsening nitrate contamination of Canterbury’s water.

"Through permitting extensive synthetic fertiliser use and dairy intensification, ECan are themselves complicit in the contamination of people’s drinking water in Canterbury. We’re now paying for that dairy intensification with tap water that risks cancer, as well as extreme weather events from the climate crisis and rivers too polluted to swim in," says Abel.

"We’re calling on the Government to take the nitrate health risk seriously by lowering the limit for nitrate permitted in drinking water, from 11.3mg/L to 0.87mg/L.

"Then we need both central and regional government to put people’s health first and stop the contamination of drinking water at source by cutting synthetic nitrogen fertiliser and lowering dairy cow stocking rates."

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