January University of Galway investigates glyphosate exposure among families

Researchers conducted the first study of its kind in Ireland, investigating the background level of exposure to the herbicide 

About one quarter of those tested found to have low levels of exposure of the chemical glyphosate

Scientists at University of Galway investigating exposure to glyphosate in families have detected low level traces of the controversial herbicide in a quarter of people tested.

The IMAGE research project ran from 2019 to 2020 and is the first of its kind to investigate levels of background exposure to glyphosate among Irish households.

Led by Exposure Science researchers at University of Galway, in collaboration with the Institute for Prevention and Occupational Medicine in Bochum, Germany and the German Environment Agency (Umweltbundesamt-UBA), the study tested urine samples collected from farm and non-farm families for the presence of glyphosate and its main human metabolite, aminomethylphosphonic acid (AMPA).

Dr Alison Connolly, exposure scientist 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. 

“Although the exposure data reported is low compared to the current acceptable daily intake value set by EFSA, our risk assessment could change following the publication of EFSAs renewal assessment in early 2023. Furthermore, the data suggests that 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.”

- Why was the study carried out? 

The research was carried out as a European project on Human Biomonitoring, the HBM4EU project, has identified a number of priority substances, including both glyphosate and AMPA, for which further information on human exposure is required to better understand the risk to human health. HBM4EU called for more research, such as the University of Galway’s IMAGE study, to characterise population exposures to chemicals such as pesticides. 

- What does the study show? 

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 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. 

- What next?

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.

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

Glyphosate is the active ingredient in over 750 products, including Roundup®. More of this herbicide is used around the world than any other, 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. 

There has been much controversy over the potential adverse health effects of this commonly used pesticide. 

Dietary exposure to pesticides can occur through ingestion of residues (i.e. glyphosate) on fruit, vegetables, grains and contaminated water or via skin contact or inhalation exposure during home use of glyphosate-based pesticide products.

The debates significantly increased when the International Agency for Research on Cancer (IARC) 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.

Glyphosate is currently approved for use in the EU, an approval which is under review by the European Commission. The final EFSA conclusion is expected in July 2023. 

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