My mother used to spray lawn edges with glyphosate, the key ingredient of Roundup. “It’s only Roundup,” she’d say, wearing her painting shirt for protection. Her relaxed attitude is common despite the label’s warnings. After all, we’ve all heard it breaks down to nothing. And it’s so darn useful, especially for farmers and growers.
There’s change afoot. New Zealand Food Safety (NZFS) has proposed raising the maximum residue level for glyphosate in food by up to 100 times in wheat, oats and barley.
And last month, the NGO, Environmental Law Initiative, took the Environmental Protection Authority to the High Court after it refused the group’s 2023 request to reassess glyphosate. The EPA ruled last July that the past decade’s barrage of published studies did not meet its test of “significant new information”, relying in part on the findings of reviews by the European Union, Australia and the US.
Here, crops haven’t been tested for glyphosate residue by the government for 10 years. In 2015-16, a third of wheat samples exceeded the maximum residue limit and one was 59 times above the 0.1 mg/kg limit. NZFS says that’s why the higher limit is proposed, noting it still falls below the threshold for safe dietary intake. About 3100 submissions on its proposal were received by the May 16 deadline.
Ian Shaw, professor of toxicology at the University of Canterbury, agrees the higher residue wouldn’t bring people near the dietary “acceptable daily intake” over a lifetime. The question is, he says, “if somebody consumed food at the amounts thought to be consumed by that particular country by dietary surveys, would they consume more than the acceptable daily intake of the chemical? I did exactly that for glyphosate at the new level, and it was thousands of times below the ADI.”
The proposed new limit is 10 mg/kg of wheat. New Zealand’s acceptable daily intake is 0.3 mg/kg of body weight. That’s 6mg daily for a 20kg child, or 21mg for a 70kg adult. A child would need to eat more than 600g of maximally contaminated wheat to breach the ADI. There’s about that much wheat in a large loaf of bread – although glyphosate tends to gather in wheat’s hard outer husk, not the inner part that makes white flour.
Shaw says he cynically thinks it would be handy to dramatically raise the residue limit given New Zealand’s likely loosening of genetic modification rules, which could open us up to “Roundup-ready” crops that survive blanket spraying for weeds. Glyphosate residues are increasing around the world, he says. “They’re almost certainly increasing because of the use of Roundup-ready crops.”
NZFS says its proposal has nothing to do with the Gene Technology Bill. Shaw believes, however, that EPA should reassess glyphosate, the penetrant chemicals it’s mixed with, and how it’s used. He’s concerned for people whose jobs involve spraying it and for environmental health: fish, invertebrates, soil health and more.
Glyphosate hasn’t been reassessed here since it was first approved in the 1970s, even though it’s now used not just as herbicide but to dry out pasture before reseeding and crops just before harvest – a practice banned in Europe.
There were hints of change in 2021 when EPA put out a “call for information”, asking, among other things, for evidence on toxicology, ecotoxicology and environmental fate. Shaw replied, attaching a review paper he wrote that’s thick with concerning scientific studies. But the EPA didn’t review submitters’ attachments, which included 62 journal articles and 22 reports, before writing its summary of the call for information.
Environmental Law Initiative lawyer Tess Upperton says nothing more came from the EPA, “so we made a ‘grounds for reassessment’ application to put the question to them – do you agree there’s significant new information out there? The EPA said no. That’s what we were challenging.” The decision on the judicial review is pending.
