One in four show low-level exposure to weed killer glyphosate – study

One in four people in Ireland have low-level exposure to the weed killer glyphosate, research has indicated.

Scientists at University of Galway investigated levels of background exposure to the herbicide in the first study of its kind in Ireland.

The European Food Safety Authority (EFSA) is assessing whether to renew the approval for the use of glyphosate in the EU after safety concerns were raised, including a potential link to cancer.

The Image research project, which ran from 2019 to 2020, tested urine samples collected from farm and non-farm families for the presence of glyphosate and its main human metabolite, AMPA.

University research
Dr Alison Connolly (left), a former University of Galway researcher, now with UCD, and Dr Marie Coggins of University of Galway (University of Galway/PA)

The project was 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 (Umweltbundesamt-UBA).

Dr Alison Connolly, who conducted the research while at University of Galway, said: “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.

“Though the quantifiable levels were low, it is essential to understand how chemical exposures can occur among different groups, particularly vulnerable people such as children.

“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.”

Dr Marie Coggins, senior lecturer in exposure science at University of Galway, said: “The glyphosate exposure data published in the Image study is relevant as the European Commission evaluate their renewal assessment for this controversial pesticide.”

She said the exposure data reported was “low” compared with the current acceptable safe daily intake value set by the European Food Safety Authority.

A total of 68 families took part in the study, 14 of which were living on farms, with one of those family members spraying glyphosate-based pesticide.

The study analysed tests from 226 people with a detailed dietary and lifestyle questionnaire.

Glyphosate was detectable in 26% of samples and AMPA was detectable in 59% 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, likely 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, i.e. from residues on foods and water.