ONE IN FOUR people in Ireland have low-level exposure to the weed killer glyphosate, new research has suggested. 

The study by scientists at University of Galway is the first study of its kind in Ireland.

It was carried out to understand better the risk posed to humans by chemicals such as pesticides, with the European Commission also currently re-evaluating glyphosates in work due to be published later this year.

The study tested urine samples collected from 68 farm and non-farm families.

The IMAGE research project, which ran from 2019 to 2020, was led by Exposure Science researchers at the University of Galwaydone in collaboration with the Institute for Prevention and Occupational Medicine in Bochum, Germany and the German Environment Agency (Umweltbundesamt-UBA).

Scientists were searching for the presence of glyphosate and its main human metabolite, aminomethylphosphonic acid (AMPA).

Controversial use

Glyphosate is the active ingredient in over 750 products, including Roundup.

Its use is considered controversial, with this publication’s sister site Noteworthy documenting its widespread use by local councils, including in playgrounds and gyms. 

Inspections by the Department of Agriculture, Food and Marine have also identified issues around its handling by retailers and wholesalers.

There has been much controversy over the potential adverse health effects of this commonly used herbicide, which is used to combat weeds and as pre-harvest treatment on some crops.

The debates intensified when the International Agency for Research on Cancer classified glyphosate as “Group 2A – probably carcinogenic to humans” in 2015. 

The European Chemical Agency’s (ECHA) Committee for Risk Assessment (RAC) have classified glyphosate as causing serious eye damage and being toxic to aquatic life. It has stated that it is not justified to classify glyphosate as a carcinogen.

‘Quantifiable levels’

Dr Alison Connolly, exposure scientist who conducted the research, said that while the “quantifiable levels of glyphosate were low”, it was important to understand how the exposure occurs 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,” Dr Connolly said.

“This study also demonstrated how beneficial human biomonitoring is for evaluating chemical exposures.” 

She said it the chemical is of public concern and “is particularly timely with the European Commission currently re-evaluating glyphosate”. 

Dr Alison Connolly, a former University of Galway researcher, now with UCD, and Dr Marie Coggins of University of Galway.

Dr Marie Coggins, Senior Lecturer in Exposure Science at University of Galway, said it was a controversial pesticide which requires further study.

She said the data suggests that occupational users of the pesticide may have a “slightly higher exposure” than background levels, which she said should be reduced further by using less harmful methods, careful chemical handling practices and the use of exposure controls such as personal protective equipment.

A total of 68 families took part in the research– 14 of whom were living on farms, with one of those family members spraying glyphosate-based pesticide. The study analysed tests from 226 people along with detailed dietary and lifestyle questionnaire. 

Glyphosate was detectable in 26% of samples. AMPA was detectable in 59% of samples. 

The daily intakes for participants were back-calculated from urinary glyphosate concentrations and compared to the acceptable daily intake. Calculated intakes were equivalent to 3% or less of the EFSA acceptable level.

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. 

They also found maximum exposures to glyphosate are low compared to the current acceptable daily intake set by the European Food Safety Authority (EFSA) without presenting an appreciable health risk. 

The researchers said that the  global scientific community has still not reached a consensus on the potential carcinogenic health effects of glyphosate.

“However, EFSA currently concludes that glyphosate is unlikely to pose a carcinogenic hazard to humans and the results of this study are interpreted using the current EFSA acceptable daily intake,” a statement from the scientists said. 

This study will enhance Europe’s understanding of glyphosate exposures among different demographic groups and contribute to scientific knowledge on exposures required for regulatory risk assessments, currently under re-evaluation by the European Commission with results due in 2023. 

Glyphosate is currently approved for use in the EU with final EFSA conclusion is expected in July.