Council continues use of controversial weedkiller, but risk to public deemed 'low'

Thursday, 6 January 2022

Protesters demonstrate against controversial weedkiller glyphosate in Brussels as the EU pesticides committee considers whether to extend its licence, in 2019.

The spraying of a controversial weedkiller in Christchurch has dramatically decreased in most areas except parks where it has increased, officially released information shows.

Glyphosate is a herbicide approved for use by the Environmental Protection Authority (EPA), but its use has long attracted public criticism but official advice has been mixed.

The Christchurch City Council planned to increase glyphosate use in 2020 to save an estimated $3.5 million in weed control, but reversed that decision after two-thirds of public submissions to its annual plan opposed it on health and environmental grounds.

Since 2016, council policy has been to use glyphosate sparingly and away from populated areas.

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There had been an increase in glyphosate use in the last two financial years within Christchurch’s community sports and recreation parks and regional parks. (File photo).

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This came after the herbicide was designated as probably carcinogenic to humans in 2015 by the International Agency for Research on Cancer. It saw several countries ban glyphosate products.

Then in 2018, American school groundskeeper Dewayne Johnson sued Roundup manufacturer Monsanto, after developing an aggressive cancer named non-Hodgkin's lymphoma.

Johnson won his case in a US court and was awarded $289m (US) and a historic lawsuit with an estimated 95,000 plaintiffs. This resulted in a $10 billion settlement with Monsanto’s new owner Bayer last year, but it continues to deny the allegations.

In 2015, glyphosate was designated as probably carcinogenic to humans by the International Agency for Research on Cancer and several countries moved to ban glyphosate products.

Then in June last year , the Assessment Group on Glyphosate (AGG), created by the European Commission to assess glyphosate, ruled that it could not be classified as carcinogenic and that the data could be used to reauthorise the substance’s use in the European Union.

In April, New Zealand’s EPA issued a public call for information on the use of glyphosate, particularly on the manufacture, importation, patterns of use, the availability of alternatives and impacts on Māori. The EPA was expected to issue a summary report from its findings in 2022.

Information obtained under the Local Government Official Information and Meetings Act (LGOIMA), showed that there had been an increase in glyphosate use in the last two financial years within Christchurch’s community sports and recreation parks and regional parks.

Glyphosate, manufactured by Monsanto, is the world’s most commonly used herbicide.

Just over 20 litres had been sprayed within Christchurch’s community sports and recreation parks in the 2019-20 financial year. This increased four-fold to more than 82 litres the following financial year.

In 2019-20, 69 litres was sprayed in regional parks and this increased slightly to just over 72 litres in 2020-21.

More than 240 litres was sprayed in the residential red zone in 2020-21, but no data was available for previous years.

“Dead bees” attended Christchurch City Council's draft annual plan submission hearings last year to protest against a council plan to start using glyphosate again.

Several factors contributed to this increase, the spokesman said.

For the community parks, newly acquired reserves with weeds contributed to some of the increase and a one-off application in certain cemeteries was needed as the use of fatty-acid, an alternative to glyphosate, could degrade heritage headstones.

Separately, some wetland areas in regional parks were deemed best treated with glyphosate.

Canterbury professor of toxicology Ian Shaw glyphosate may not be broken down in the environment as rapidly as once thought.

However, there had been a reduction in the herbicide’s use around waterways and in urban areas.

This included median, centre and splitter islands, back of kerbs and edges, roundabouts, some gardens and hillside bank vegetation.

Between January and December 2020, 760 litres was applied while between January and September this year only 566 litres was sprayed.

A council spokesman said glyphosate was used “sparingly and only when necessary”. Where possible, manual methods were used and so too was mulching on applicable gardens.

Despite this, glyphosate remained the “most cost-effective herbicide for controlling weeds on pavements and hard surfaces”, he said.

Its use on Banks Peninsula had dropped from aboutbout 1000 litres to 800 litres in this financial year.

Canterbury University professor of toxicology Ian Shaw, who has written many scientific reports on glyphosate, said the amount being sprayed appeared to be quite low and most likely wouldn’t pose much of a risk to the public.

But there could be harm to the contractors undertaking the spraying if they were not wearing appropriate personal protective equipment (PPE).

He said for the herbicide to potentially cause cancer, which has been reported overseas, repeat doses over a long period of time would be needed and the chances of that were 'very small'.

It has been widely argued that glyphosate was rapidly broken down in the environment, but that may not be entirely true, Shaw said.

“We're beginning to think that might not be the case, it's broken down to some extent but not as rapidly as the original ideas suggested.”

The main concern was that little was known about glyphosate in New Zealand and Shaw hoped the EPA would do a full risk assessment into its use and its implications on the environment, people and food.

'I would like to see a risk assessment made purely scientifically to say right, here's the hazard, here's the exposure and here's the risk.'

He said it seemed “unnecessary” to be spraying roadsides and public park areas, so they look “nice and neat”.

'I think we should be reducing our use of glyphosate by looking where it's absolutely necessary and keeping its use there.”

Shaw said glyphosate use may be necessary in the agriculture sector as it reduced the amount of soil tilling.

“That’s really important to New Zealand because our soils are quite fragile. And they get eroded very quickly and so using glyphosate instead of ploughing is environmentally quite positive.”

EPA general manager of hazardous substances and new organisms Dr Chris Hill said the authority was still evaluating the more than 460 responses received following the call for information on glyphosate.

He said there was almost an even split between responses from the public and from users and suppliers of glyphosate. The information would help inform the authority’s next steps.

He said if the authority carried out a reassessment, it may include impacts on human health, the environment, the economy, people and communities, Māori culture, and international obligations.

He expected a summary report to be published early this year to ensure the agency would be “in a good position toact on the findings of significant overseas reviews expected to be concluded in 2022”.

Hill said many factors influenced the levels of exposure associated with herbicide use, not just the quantity applied.

The area treated was an important consideration, as was the chemical properties of the substance and the likelihood of exposure to significant quantities, he said.

Herbicides containing glyphosate remained safe to use when the rules surrounding their use were followed, Hill said.

They included wearing personal protective equipment (PPE) such as gloves, goggles and boots, spraying during calm and dry conditions at designated use rates and storing the chemical appropriately.