An investigation into exposure to glyphosate in Irish families has detected low -level traces of the controversial herbicide in a quarter of people tested.
The research project is the first of its kind to investigate levels of background exposure to glyphosate among Irish households.
Glyphosate is the most frequently used weedkiller in the EU. The European Commission is re-evaluating its use, primarily because of human health concerns. It has been or will soon be banned in at least 10 countries, and at least 15 others have restricted its use. Farmers in Germany must stop using it from 2024.
Led by exposure science researchers at the University of Galway, in collaboration with the Institute for Prevention and Occupational Medicine in Bochum, Germany, and the German Environment Agency, the study tested urine samples collected from farm and non-farm families for glyphosate and its main human metabolite, aminomethylphosphonic acid (AMPA).
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Conducted in 2019-2020, the findings of the study are being released on Monday.
“This study produced important results on human exposures to a chemical of public concern and is particularly timely with the European Commission currently re-evaluating glyphosate,” said Dr Alison Connolly, who conducted the research while at University of Galway.
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Though the quantifiable levels were low, it was essential to understand how chemical exposures can occur among different groups, particularly vulnerable people such as children, she said. “This information is necessary for conducting robust regulatory risk assessments, managing exposure levels, and fully understanding their effect on human health. This study also demonstrated how beneficial human biomonitoring is for evaluating chemical exposures,” she said.
Dr Marie Coggins, senior lecturer in exposure science at UG said: “The glyphosate exposure data is relevant as the European Commission evaluate their renewal assessment for this controversial pesticide.
“Although the exposure data reported is low compared to the current acceptable daily intake value set by [the European Food Safety Authority] EFSA, our risk assessment could change following the publication of the European Food Safety Authority’s renewal assessment in early 2023,” she said.
The data suggests occupational users may have a slightly higher exposure than background levels, “which could and should be reduced further by substitution with less harmful methods, careful chemical handling practices and the use of exposure controls such as personal protective equipment”, Dr Coggins said.
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A total of 68 families took part – 14 of whom were living on farms, with one of those family members spraying glyphosate-based pesticide. The study analysed tests from 226 people and their responses to a detailed dietary and lifestyle questionnaire. Glyphosate was detectable in 26 per cent of samples. AMPA was detectable in 59 per cent of samples.
There was no statistical difference between farm and non-farm families’ exposures, though higher concentrations were detected among some fathers living on farms, probably because they sprayed glyphosate-based pesticide products the day before sampling.
Researchers said the higher detection frequency for AMPA may be due to dietary exposure, from residues on foods and water. They also found maximum exposures to glyphosate are low compared to the acceptable daily intake set by the EFSA without presenting an appreciable health risk.
The global scientific community has not reached a consensus on the potential carcinogenic effects of glyphosate. However, EFSA concludes glyphosate is unlikely to pose a carcinogenic hazard to humans – the results of this study are interpreted using the EFSA acceptable daily intake.
In Ireland half of glyphosate’s use is on farms. The rest is in amenity areas, parks and golf courses. While most regulators worldwide have determined glyphosate to be safe, Bayer has settled nearly 100,000 US lawsuits for $10.9 billion, denying claims that Roundup – its trade name – caused cancer.
Glyphosate is the active ingredient in more than 750 products, including Roundup. It is used to combat weeds, as a pre-harvest drying treatment on certain food crops, in home gardens and in parks, public spaces, lawns, gardens and roadsides.
Dietary exposure to pesticides can occur through ingestion of residues (ie glyphosate) on fruit, vegetables, grains and contaminated water or via skin contact or inhalation exposure during home use of glyphosate-based pesticide products.
The International Agency for Research on Cancer classified glyphosate as “Group 2A – probably carcinogenic to humans” in 2015.
