The Environmental Protection Authority (EPA) is calling for information on the use of the herbicide glyphosate in New Zealand.
This weed killer has been used by home gardeners, farmers, and councils in New Zealand since the 1970s.
Although it is commonly known as the active ingredient in Roundup, there are 89 mixtures containing glyphosate that are approved for use in this country.
The EPA said it was seeking information from New Zealanders - including industry and the general public - about the manufacture, importation, and patterns of use of glyphosate in New Zealand.
It was also interested in information on the availability of alternatives, and any impacts on Māori.
Glyphosate was currently approved for use in the European Union until 15 December 2022, and could be used there until that date, EPA's General Manager, Hazardous Substances and New Organism Dr Chris Hill said.
The European Chemicals Agency (ECHA) and the European Food Safety Authority (EFSA) were in the process of reviewing the classification and approval of glyphosate, with their conclusions set to be released in mid-2022, Hill said.
"Issuing a call for information now will enable us to have a greater understanding of the New Zealand context by the time the EU findings are published, and ensure we're better prepared to assess those findings."
There was an ongoing public debate about the effects of glyphosate on environmental and human health, Hill said.
"Our position at this time remains that products containing glyphosate are safe to use when all the rules (controls) around their use are followed."
"This is in line with the current regulatory opinion in Australia, Canada, the European Union and the United States."
The EPA monitored international developments and continually reviewed global research on hazardous substances, including glyphosate, Hill said.
"We have no evidence that risks associated with using glyphosate, or its hazardous nature, have changed."
However, the EPA felt it was the right time to take another look at glyphosate, Hill said.
"This is something we have been considering for some time, and is in line with our stance as a proactive regulator - putting the environment and the health of people front and centre."
The call for information would provide the EPA with more detail on how glyphosate was currently being used in New Zealand, as it was possible it had changed since it was approved for use.
"We want to understand whether products containing glyphosate may be damaging the environment or human health, despite the clear rules in place. We also want to know about the economic benefits of glyphosate's use, and any potential alternatives. The information gathered will be used to help inform our next steps," Hill said.
Meanwhile, most experts welcomed the call for information.
Dr Belinda Cridge, mechanistic toxicologist and Technical Lead for Drinking Water, Institute of Environmental Science and Research (ESR), said it was important the EPA continually reassessed chemical use.
"With major reviews occurring in the US and EU to update our understanding of the risks and benefits of glyphosate use, it is important that the EPA has New Zealand-relevant information to allow decisions as to the future use of the chemical here," she said.
Cridge encouraged people who had concerns or comments about glyphosate use in New Zealand to participate in the process "to allow their insights to be captured."
Professor of Toxicology Ian Shaw, of the University of Canterbury said he was "amazed" the EPA hadn't included glyphosate in its pesticide review sooner.
"The news that they are calling for information on its use is encouraging because it suggests that they might at least be interested in considering its potential environmental and human health impact," he said.
Shaw said he had conducted his own review of glyphosate's chemistry, use and toxicity to both humans and ecosystems, as a means of assessing its risk.
Although he concluded that glyphosate's acute effects in both humans and on the environment were likely negligible, "we have too little data to determine its long-term effects definitively".
"However, the available data point firmly to long-term environmental effects and effects in workers handling glyphosate regularly without appropriate personal protective equipment. In contrast, the recent reports of residues in food (e.g. honey) are very unlikely indeed to negatively affect consumer health."
His work will be published in the New Zealand Science Review.
Associate Professor Brian Cox, Director of the Hugh Adam Cancer Epidemiology Unit, University of Otago, said it was appropriate the EPA reviewed the use of glyphosate.
"This is necessary to assess the balance of the evidence of risk from the use of glyphosate and the views of users, the public, and New Zealand industry," he said.
In 2015 the International Agency for Research on Cancer (IARC) classified glyphosate as a probable carcinogen, (a possible cancer-causing agent in their Group 2A category), Cox said.
"That is, the IARC considered there was limited evidence that glyphosate may cause cancer, but any association with cancer may be due to other things. Herbicide use is seldom exposure to just one specific product, and the dose, duration, type, and frequency of exposure is relevant to any potential risk."
However, Dr Kerry Harrington, senior lecturer in Weed Science, Massey University, was concerned policy around glyphosate in Europe appeared to be "more swayed by public perceptions than facts".
Most toxicologists across the world agreed glyphosate was unlikely to cause cancer in humans, Harrington said.
"If glyphosate was to be removed from use, the possible replacements are either less effective or likely to be more damaging to the environment than glyphosate," he said.
Glyphosate use in agriculture had enabled much more direct drilling when establishing crops and pastures, Harrington said.
Direct drilling involved establishing crops without cultivating the soil, which reduced soil erosion, he said.
"No other herbicide can be used to allow satisfactory direct drilling without weed problems afterwards."
"Councils will have difficulties keeping weeds under control in our communities without needing to increase costs considerably from using less effective alternatives."
Harrington hoped the EPA would use the call for information "to reassure themselves and the community that it is correct to continue using glyphosate within New Zealand."
(Click here for Dr Harrington's conflict of interest statement)
The call for information will remain open until 5.00 pm August 27, 2021.