'It isn’t safe': Dunedin to keep weed spray linked to cancer

Weeds growing between the kerb and footpath in Islington St, North East Valley. PHOTO: GERARD O’BRIEN

A chemical which a Dunedin councillor says is linked to cancer will continue to be sprayed on weeds across the city.

The continued use of the herbicide spray glyphosate divided Dunedin City councillors at a meeting this week, arguments centring on environmental and health concerns versus cost.

Councillors — who voted eight to seven in favour of continuing its use — were told one environmentally friendly alternative could cost nearly 15 times as much and would need to be applied three times as often.

Council staff clarified glyphosate killed plants through to the roots, while some treatments only affected weeds at a surface level.

Cr Jim O’Malley, who has a background in pharmacology, said glyphosate took a long time to naturally degrade.

It could build up in the environment and disperse throughout waterways, and he believed the chemical would inevitably be determined too dangerous and would be taken off the market, similar to DDT.

"We know we have an intrinsically dangerous molecule; we know that it’s been associated with cancers ... There’s plenty of evidence out there to suggest that it isn’t safe."

He urged council to remove it from use "as quickly as we can", and suggested a motion to reduce glyphosate use and substitute it with less toxic alternatives.

Cr Steve Walker, who led the debate, said he would reluctantly vote for the status quo.

"I do feel actually slightly caught between a rock and a hard place, in essence a bit of a Catch-22 between environmental health and cost."

It was "perverse" to use poison to kill weeds, which he compared to landfills, and he was not comfortable with killing important insect life.

However, he accepted council had other responsibilities and said they could not afford to conduct their infrastructural obligations in a manner that would pose "hefty financial implications"on to ratepayers.

Cr Mandy Mayhem, who voted against the motion, said she preferred none of the available options and signalled a motion to mash two of them together, to explore broader options of weed control and a reduction of glyphosate-based methods.

"As city governors, we can do things differently and I would like to see us being role models around better environmental practice."

The effects of glyphosate could extend to biodiversity, aquatic life and even exports, she said.

Cr Lee Vandervis, who voted against, agreed the council should look at significantly reducing its glyphosate use, even if that meant reducing its level of weed control.

"If people really want their frontages to be absolutely weed free, and want to use glyphosate themselves, well that’s still an option," he said.

He supported as many options as possible that reduced the level of glyphosate, and hoped an alternative motion would arise.

Cr David Benson-Pope, who voted for, said the economic implications of the other options were "two powerful to ignore", but noted the door to change was not yet closed.

In his closing remarks, Cr Walker said he would not die on a hill over this motion.

"This is probably the only time I’ve moved a motion ... as an elected member of 15 or 16 years that I’d probably be happy to lose," he said.