Glyphosate and NZ: What the scientists say
Despite Roundup being widely used by gardeners and farmers, there has never been a case in New Zealand similar to that in California.
Federated Farmers spokesman Andrew Hoggard said he’d be concerned if Roundup was banned, as it was effective for spraying out paddocks between pastures, and there were no alternatives as useful.
Rigorous testing had also shown that concerns about glyphosate residue in milk products were unfounded.
Yet, on the back of the ruling, Associate Environment Minister Eugenie Sage asked the Environmental Protection Authority (EPA) to consider adding Roundup to its hazardous substance reassessment list in the light of the decision. The EPA remained of the view that Roundup was safe to use.
After the International Agency for Research on Cancer (IARC) report came out, the agency commissioned Dr Wayne Temple, a toxicologist and former director of the New Zealand National Poisons Centre, to undertake a review.
Temple found glyphosate was unlikely to be carcinogenic to humans or genotoxic — damaging to genetic material or DNA — and should not be classified as a mutagen or carcinogen under New Zealand law.
This conclusion was formed on the back of human and animal studies, including many not looked at by the IARC, and the findings were peer-reviewed by experts.
Not all toxicologists were happy with it though.
The University of Canterbury’s Dr Ian Shaw said Temple’s review didn’t appear to have covered the possibility of non-genotoxic carcinogenesis, where some chemicals that caused cancer didn’t directly alter genes.
“This was particularly surprising because experiments have shown that glyphosate can interact with a cell receptor that stimulates some cells to grow — this is the way some non-genotoxic carcinogens work,” Shaw said.
“In view of this, and other aspects of Temple’s report, I found the EPA’s decision lacked scientific rigour.”
Still, scientists argued the US ruling shouldn’t prompt a knee-jerk ban of Roundup.
“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,” said Associate Professor Brian Cox, a cancer epidemiologist at the University of Otago.
“A sudden reaction to one case in one US law court, that has not yet gone to the appeal court, is not an appropriate method of developing health policy in New Zealand.”
University of Otago toxicologist Dr Belinda Cridge argued Roundup remained one of the safer options.
“My standard advice is for people to not use chemicals where they don’t need to, know what chemicals you are using and be rigorous about safety equipment,” she said.