Concern over nitrates prompt water testing

Growing anxiety about water nitrate levels in part of rural Canterbury has led Greenpeace to set up a testing station for concerned property owners.

Greenpeace spokesperson Zoe Deans confirmed testing would take place on May 29 from 9am to 1pm at a yet to be confirmed venue in the Selwyn district.

Deans said landowners had expressed concerns in the wake of a major Danish study published in 2018 that found a significant increase in bowel cancer when nitrate levels were just 0.87 milligrams and a 15 per cent increase at 2.1mg per litre.

The current safe level in New Zealand, as mandated by the World Health Organisation (WHO), is 11.3mg per litre, but Greenpeace has petitioned the Government to review what the safe drinking standard is.

High nitrate levels have been found in previous testing around Dunsandel, sparking fears about how safe private residents’ water really was.

Last year, Selwyn landowner Mike Glover held a testing session at the Springston Hall for concerned residents and was surprised to see 100 people turn up.

Using a professional nitrate tester, he tested 80 samples and delivered some shocking results, including a 11.5mg per litre reading near Dunsandel. Stuff has also been told of one resident, who did not want to be named, recording 14mg per litre.

The Selwyn district has specifically been under the microscope because of high nitrate levels that regional council Environment Canterbury (ECan) blamed on farming intensification.

New Zealand Federation of Freshwater Anglers president Peter Trolove said they would conduct the tests for Greenpeace using a precise sensor.

Trolove previously found higher levels on several sites around the Dunsandel catchment, including 9.8mg per litre at the Ellesmere golf club.

He said Dunsandel and Bankside were particularly bad because they had porous soils that leached easily.

Deans said ECan information that indicated nitrate levels were likely to spike for at least another decade were worrying.

Concerned private well owners around Darfield were given the opportunity to test nitrate levels in their drinking water for free on Wednesday.

Organised by the Selwyn Waihora Water Zone Committee, the optical sensor indicative test allowed more than 20 concerned residents to ascertain if their private water supply warranted further lab testing.

‘‘Nitrates have been in the media, so there is a general awareness around water and water quality,’’ co-chair Fiona McDonald said.

The committee wanted to raise awareness among private landowners of their responsibility to test their bores regularly.

Jennie Vandervalk brought water from her rural property near Rolleston because of concerns she had about conflicting reports on what constituted a safe nitrate drinking water level. The test showed an indicative reading of 7.5mg per litre, which was higher than she was comfortable with.

Vandervalk said the result would make her research the nitrate issue further.

Kylie McEwen, who lives between West Melton and Kirwee, had been following the recent Danish study and wondered if the current ministry standard should be reviewed. Pregnant and with a toddler and elderly parents living on the property, McEwen thought her indicative test result of 6.2mg per litre was higher than she was happy with, but was pleased the levels had not increased on a test conducted two years ago.

ECan groundwater science manager Dr Carl Hanson said it was important people with private wells understood it was their responsibility to get their water tested to ensure their supply was safe. Hanson said ECan expected some wells would increase in nitrate levels by ‘‘a couple’’ of mg per litre in the next five years.