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Using human biomonitoring to understand chemical exposures among the population

Tuesday, 21 January, 2025

Summary

Chemicals form an intricate part of our daily lives. However, it is necessary to ensure the safety of people and the environment when using chemicals and to control environmental pollution. This is particularly important as the World Health Organization estimates that global production of chemicals will almost quadruple by 2050 compared to 2010 and nearly three-quarters of industrial chemicals produced in the EU in 2017 were deemed hazardous to human health, while only 500 chemicals were considered sufficiently regulated and monitored regularly. This has highlighted a need to develop a monitoring programme to evaluate chemical exposures and understand the related risks to human health. Dr Connolly is an exposure scientist who conducts human biomonitoring studies to investigate chemical exposures specifically related to pesticides. Human biomonitoring is described by the World Health Organization as an important policy-making tool in the field of health, as it provides measured data on the range and magnitude of chemical exposures in the population which it utilises to assist in controlling and reducing these exposures.

Research description

Many EU initiatives, such as the European Green Deal and the EU Chemicals Strategy for Sustainability, have identified the need to develop a framework of indicators to monitor the drivers and impacts of chemical pollution and to measure the effectiveness of chemical legislation.

Dr Connolly’s human biomonitoring studies include measuring human exposure to the most widely used herbicide in the world, Glyphosate. This is the active ingredient in over 750 different pesticide products, including Roundup® products. This research measured exposure levels and evaluated the risks among professional gardeners and agricultural workers. Dr Connolly found low-level exposures of Glyphosate in these groups and actually found exposure levels comparable to those of farmers who typically use larger quantities of pesticides.

Dr Connolly produced the first study carried out internationally to evaluate the human biological half-life of glyphosate, which was approximately a third lower than previously estimated. The biological half-life of glyphosate is the time taken for the concentration of glyphosate in the human body to decrease by half. Further studies investigating exposures among families found a quarter of participants had low levels of glyphosate exposure, but two-thirds had levels of the main metabolite of glyphosate, aminomethylphosphonic acid. This highlighted the need to include this metabolite in future studies, as it is assumed to have the same adverse effects as glyphosate.

Dr Connolly’s current studies are investigating exposures to the most widely used class of insecticides worldwide, neonicotinoid insecticides (neonics) and will evaluate exposures to seven of the most widely used neonics. Initial studies have evaluated environmental exposures to neonics and found that three-quarters of the participants had exposure to at least one of the neonics. Further studies will evaluate professional and amateur gardeners using pesticides, vets and animal shelter workers, and pet owners using flea treatments at home.

Dr Connolly is also leading a feasibility study, which will determine whether a nationwide human biomonitoring surveillance programme could be developed in Ireland, similar to those found in Germany, Slovenia, the US, and Canada.

More information on human biomonitoring studies can be found on the Human Biomonitoring Programme for Ireland website and the EIRE study website.

Research impact

Health impact

These human biomonitoring projects have had a positive impact on scientific, educational, policy-oriented, societal and international engagement. The studies contribute to understanding environmental risks due to chemical exposures, which will benefit the population's health by identifying appropriate policy responses and informing future national and EU chemical policy.

These types of studies help evaluate current, emerging, and novel chemical safety issues and contribute to both the Next Generation Risk Assessment and to ambitious EU goals on exposure. Ultimately, these monitoring results will contribute to a decrease in overall human health risks in the EU.

Academic and educational impact

Dr Connolly has integrated research-led teaching of human biomonitoring strategies across programmes at the UCD Centre for Safety and Health at Work to meet the needs of the future workforce, and also to aid the progression of this research in Ireland. Dr Connolly has also produced scientific publications, which are the first of their kind and contribute to knowledge and scholarship on the topic, including:    

  • The first study to investigate the human biological half-life of glyphosate;    
  • The  first study to investigate glyphosate exposures among amenity horticulturists using human biomonitoring strategies;
  • A study developing a method for analysing glyphosate and its main breakdown product in urine, which was the first method worldwide to undergo two international external review processes for glyphosate.

On this specific topic, Dr Connolly has over 620 citations, an h-index of 12 and has co-authored 19 peer-reviewed journal articles, all published in relevant high-impact international journals, two of which were awarded Editor’s Choice.

Dr Connolly has initiated the first study of its kind for Ireland to evaluate the feasibility of a national programme on addressing risks from chemical exposure, and is currently contributing to the international initiative, Partnership for the Assessment of Risks from Chemicals (PARC) which includes 200 institutions across 29 countries and is funded under Horizon 2020.

Political impact

These studies have made a significant contribution to the development of Ireland’s Chemical Policy and, in the broader context, Europe’s Chemicals Policy, as they provide new real-world data that will improve estimates of environmental chemical exposures. This information is required by regulators to refine policies and interventions to reduce and eventually eliminate harmful chemical exposure. In particular, six of the scientific papers focused on glyphosate exposures, of which Dr Connolly was first author, were cited in the recent re-evaluation and approval of the use of glyphosate on the EU market by the European Commission.

Social impact

Dr Connolly's research provides recommendations to workers to assist with reducing chemical exposures to as low as reasonably practicable and has developed a (opens in a new window)guidance document. Additionally, articles on the research have been published in national newspapers, including the (opens in a new window)Irish Farmers Journal, the (opens in a new window)Galway Advertiser, the  and the (opens in a new window)Irish Times. Dr Connolly was also invited to speak on (opens in a new window)RTÉ Radio One’s News at One programme, one of the most popular news programmes in Ireland. This combined media coverage raised awareness of chemical safety among the general public. With over 20 national publications on the study, as well as giving radio interviews and speaking at public events, Dr Connolly has contributed to the widespread dissemination of study results which has had significant societal impact.

Research team and collaborators

UCD research team

  • Dr Alison Connolly, Assistant Professor and Programme Director of the UCD Higher Diploma of the Safety, Health and Well-Being at Work and Principal Investigator and project lead for the exposure science research team;
  • Dr Richa Singh, a postdoctoral researcher conducting the feasibility study for developing a national human biomonitoring programme for Ireland;
  • Dr Sewon Lee, postdoctoral researcher evaluating gardeners' exposures to neonicotinoid insecticides using human biomonitoring strategies;
  • Darragh Doherty, PhD candidate, researching exposures among users of flea treatments containing neonicotinoid insecticides using human biomonitoring strategies.

Collaborators

  • Dr Holger Koch, Division Head of Laboratory for Human Biomonitoring in the Institute of Prevention and Occupational Medicine in Bochum, Germany, and Honorary Professor at The University of Queensland, Australia (QAEHS). Dr Koch is a world-renowned scientist specialising in human biomonitoring, specifically analytical method development and metabolism studies. Dr Koch conducts laboratory analyses for Dr Connolly’s recent projects and mentored her during her Marie Curie postdoctoral fellowship.
  • Dr Marie Coggins, Senior Lecturer and Chartered Fellow of the Faculty of Occupational Hygiene at the British Occupational Hygiene Society, University of Galway, Dr Connolly’s mentor during her PhD and throughout her early career postdoctoral studies.
  • Dr Marike Kolossa-Gehring, a world leader in HBM and André Conrad, an expert in human biomonitoring of glyphosate exposures at the German Environment Agency are expert advisors across Dr Connolly’s studies.
  • Dr Karen Galea, Dr Ioannis Basinas and Dr Kate Jones were external collaborators during Dr Connolly’s PhD studies and contributed to study design, chemical analysis and statistical analysis and interpretation.

Funding

Irish Research Council Marie Skłodowska-Curie Actions [2019-2021]

  • The research fellowship, IMAGE: Irelands bioMonitoring Assessment of Glyphosate Exposure, was funded by the Irish Research Council Marie Skłodowska-Curie Actions Programme entitled CAROLINE – Collaborative Research Fellowships for a Responsive and Innovative Europe (grant agreement No 713279). CAROLINE funds experienced researchers to conduct research relevant to the themes of the United Nations 2030 sustainability goals, where a key feature of the programme is the collaboration between the academic sector and non-governmental organisations. The IMAGE's overarching aim was to assess environmental exposures to glyphosate and its main metabolite, aminomethylphosphonic acid, in Irish families (parents and children) using a newly developed human biomonitoring strategy.

SFI Pathway Principal Investigator and PhD supervisor [2022-2026]

  • This SFI four-year project involves the management of the EIRE nEonicotinoid Insecticide exposuREs study, which aims to measure neonicotinoid insecticides (NNIs) exposures among gardeners working with these products, their families, bystanders and the general population.

EPA-funded project [2023-2025]

  • This study was awarded under the Delivering a Healthy Environment 2022 Call for the Human Biomonitoring for Ireland (HBM4IRE) project. The project’s overall aim is to evaluate the criteria required to develop a national Human Biomonitoring surveillance programme for Ireland to contribute to monitoring environmental chemical exposures.

EPA-funded project [2025-2028]

  • The Human Biomonitoring for Ireland (HBM4IE) environmental chemical exposure study is funded under the theme Delivering a Healthy Environment: Towards Zero Pollution. The project's overall aim is to conduct human biomonitoring (HBM) campaigns to collect HBM samples to evaluate environmental chemical exposure for ten specific priority chemical groups, which will be conducted in collaboration with the (opens in a new window)PARC initiative. 

Selected media

  • Connolly, A., Jones, K., Basinas, I., Galea, K. S., Kenny, L., McGowan, P. and Coggins, M. A. (2019) Exploring the half-life of glyphosate in human urine samples, International Journal of Hygiene and Environmental Health, 222(2), PP. 205-210, (opens in a new window)https://doi.org/10.1016/j.ijheh.2018.09.004.  Citations: 106.
  • Alison Connolly and Holger M. Koch, 2023, Invited Perspective: The Continuing Debate—Is Glyphosate a Problem, and Can an Organic Diet Protect Us from Exposures?, Environmental Health Perspectives 131:7 CID: 071304, (opens in a new window)https://doi.org/10.1289/EHP13053. Citations: 5.
  • Connolly, A.; Koch, H.M.; Bury, D.; Koslitz, S.; Kolossa-Gehring, M.; Conrad, A.; Murawski, A.; McGrath, J.A.; Leahy, M.; Brüning, T.; Coggins, M.A. A Human Biomonitoring Study Assessing Glyphosate and Aminomethylphosphonic Acid (AMPA) Exposures among Farm and Non-Farm Families. Toxics 2022, 10, 690. (opens in a new window)https://doi.org/10.3390/toxics10110690.  Citations: 16.
  • Connolly, A.; Coggins, M.A.; Koch, H.M. Human Biomonitoring of Glyphosate Exposures: State-of-the-Art and Future Research Challenges. Toxics 2020, 8, 60, (opens in a new window)https://doi.org/10.3390/toxics8030060. Citations: 92.
  • Connolly, A., Koslitz, S., Bury, D., Brüning, T., Conrad, A., Kolossa-Gehring, M, Coggins, M.A., Koch, H.M. Sensitive and selective quantification of glyphosate and aminomethylphosphonic acid (AMPA) in urine of the general population by gas chromatography-tandem mass spectrometry. 2020, Vol: 1158, Page: 122348. (opens in a new window)https://doi.org/10.1016/j.jchromb.2020.122348. Citations: 39.
  • Connolly, A., Coggins, M. A., Galea, K. S., Jones, K., Kenny, L., McGowan, P., Basinas, I. (2019) Evaluating Glyphosate Exposure Routes and Their Contribution to Total Body Burden: A Study Among Amenity Horticulturalists, Annals of Work Exposures and Health, Volume 63, Issue 2, Pages 133–147, (opens in a new window)https://doi.org/10.1093/annweh/wxy104. Citations: 43.
  • Connolly, A., Leahy, M., Jones, K., Kenny, L., Coggins, M.A., (2018) Glyphosate in Irish adults – A pilot study in 2017. Environmental Research 165, 235-236, (opens in a new window)https://doi.org/10.1016/j.envres.2018.04.025.Citations: 71.
  • Connolly, A., Basinas, I., Jones, K., Galea, K. S., Kenny, L., McGowan, P. and Coggins, M. A. (2018) Characterising glyphosate exposures among amenity horticulturists using multiple spot urine samples, International Journal of Hygiene and Environmental Health, 221(7), 1012-1022. (opens in a new window)https://doi.org/10.1016/j.ijheh.2018.06.007. Citations: 56.
  • Connolly, A., Jones, K., Galea, K.S., Basinas, I., Kenny, L., McGowan, P., Coggins, M. (2017) Exposure assessment using human biomonitoring for glyphosate and fluroxypyr users in amenity horticulture. International Journal of Hygiene and Environmental Health 220, PP. 1064-1073, (opens in a new window)https://doi.org/10.1016/j.ijheh.2017.06.008. Citations: 83.
  • Zare Jeddi, M., Pasanen-Kase, R., Bartonova, A., Conrad, A., Paini, A., Arnot, J., David, A., Mustieles, V., Fernandez, M., Barouki, R., Viegas, S., Bopp, S., Cubadda, F., Schulze, F., Louro, H., Sepai, O., Verhagen, H., Mol, H., Philippe, Antignac J., Audouze, K., Ali, I., Jones, K., Galea, K., Kujath, P., Brennan, L., Hopf, N., Santonen, T., Duca, R., Benfenati, E., Sanchez-Pla, A., Connolly, A., Kolossa-Gehring, M., Roosli, M., Gant, T., Lobo Vicente, J., Trier, X., Bessems, J. Developing human biomonitoring as a 21st century toolbox within the European exposure science strategy 2020–2030, Environment International, 168, 107476 (2022), (opens in a new window)https://doi.org/10.1016/j.envint.2022.107476. Citations: 29.
  • Reale E, Zare Jeddi M, Paini A, Connolly A, Duca R, Cubadda F, et al. Human biomonitoring and toxicokinetics as key building blocks for next generation risk assessment. Environment International. 2024;184:108474. (opens in a new window)https://doi.org/10.1016/j.envint.2024.108474. Citations: 4

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