A controversial weedkiller could be pulled from parks and reserves around Marlborough, as a review shows the council uses close to 3000 litres of glyphosate a year.

Photo: LDR / Chloe Ranford

The Marlborough District Council is to look at pine oil sprays, hand removal and mowing as alternatives to glyphosate in parks and reserves, which currently get about 185 litres a year.

The council also uses about 1700 litres a year on rivers, and 700 litres on roads.

The glyphosate review comes after Green Party Kaikōura convenor Glenda Barnes submitted to the council's annual plan last year, asking to have glyphosate banned from public spaces.

Councillor Jamie Arbuckle said he originally wanted glyphosate, commonly found in herbicide Roundup, banned after her submission, but had reconsidered, and floated the "achievable" goal of removing it from parks and reserves.

"There's a time and a place to use it," Arbuckle said.

"There is concern amongst constituents around the use of glyphosate, and if information comes to hand that its toxicology isn't what we think it is, then we have to be flexible and change."

Council environmental science and monitoring manager Alan Johnson said the "biggest problem" was glyphosate alternatives were too costly or not good at controlling weeds.

A report he presented said that many plant-based alternatives could still cause skin irritation, and eye or lung problems.

"Glyphosate is seen, from a council perspective, as a staple tool," Johnson said at an environment committee meeting last week.

The council used glyphosate "right across the spectrum", but especially in its rivers, parks and biosecurity departments.

Glyphosate - the most widely used weedkiller in the world - was classified as "probably carcinogenic to humans" by the International Agency for Cancer Research (IARC) in 2015, but was later reviewed by New Zealand's Environmental Protection Authority (EPA) in 2016 as safe to use.

It has been used in New Zealand for more than 40 years.

A new nationwide study tested wells for glyphosate for the first time in 2018, and water in Marlborough did not return positive results. Only one of the 135 wells tested in New Zealand returned positive, but it was within safe drinking levels.

Photo: LDR / Chloe Ranford

Johnson said despite those results, the council would continue to look at alternatives to glyphosate, and continue checking contractors were complying with its herbicide regulations.

The council accepted his report, and agreed to examine the viability of alternative weed killing methods in the region's parks and reserves through the assets and services committee.

Barnes said she was "feeling quite positive" about the council's approach to the herbicide, and its push to minimise glyphosate.

"They'd be great role models if they took glyphosate out of parks and reserves in Marlborough," she said after the meeting.

In 2016, the Christchurch City Council limited the use of glyphosate to sites closed to the public, or where no other method was possible. It used fatty acid sprays and hand removal instead.

Barnes said the report showed Christchurch's council had mostly achieved its objective, despite having to do more site visits.

Councillor Francis Maher said the issue was "particularly difficult" because different world authorities had different views.

"I think glyphosate has got a bad name worldwide because it's been used in different ways, [and] getting into the food chain."

Rural representative Ross Beech said he thought council contractors did well to minimise the amount of glyphosate used, and urged the public to "take note" for their own backyards.

Where herbicide is used:

Rivers - 1746 litres

​Roads - 728 litres

Parks and reserves - 185 litres

Miscellaneous - 85 litres