A group of 42 scientists, researchers and other project partners gathered at the recent POLYRISK General Assembly, held in Berlin from 1-3 November 2022, to take part in discussions around project progress, data gathered on microplastic and nanoplastic particles (MNP) samples and potential immunological and toxicological effects of such particles, as well as to exchange updates on human exposures studies.

Partners took part in technical sessions that focused on ways to increase collaboration across the project’s different working areas, in particular between groups working on assessment methods and analysis protocols, while examining how to characterize MNPs. Several PhD students presented summaries of data gathered so far on the potential effects of MNPs on inflammation and immune modulation and cellular response.

In recent months, advances have been made on human exposure studies to MNPs in real-life scenarios and POLYRISK’s General Assembly provided a setting to go over updates on the status of these studies. For example, Esther Lenssen, a PhD student at the University of Utrecht presented an urban traffic exposure study that she led. Throughout the study, which ended in October 2022, participants were exposed to varying loads of traffic in three locations in Utrecht. Different measurements, including a questionnaire, blood collection and lung function, were performed before and after their exposures. Esther and her team will now move on to analysing the data collected to assess MNP concentrations in blood and short-term immuno-toxicological health effects.

Another example of the real-life scenarios POLYRISK researchers are examining came from Hubert Dirven and Berit Brunstad Granum from the Norwegian Institute of Public Health (NIPH), who provided an overview of the first phase of a study that examines the potential effects of exposure to inhalation to particles while playing indoor soccer on indoor field turfs made with infill from recycled car tyres. In this particular study, participants will take part in two separate soccer matches. Partners at NIPH will then proceed with the analysis of collected blood samples and air filters, monitor biomarkers of immune system effects in the soccer players’ blood, and compare inflammatory biomarkers before and after matches to determine if there is a pro-inflammatory effect of physical activity versus MNP exposure.

Discussing challenges and next steps in the coming months, Raymond Pieters (Project Coordinator of POLYRISK, from the University of Utrecht) noted that “by the end of this project, we expect to have very well-defined risk assessment framework with matching methods for exposure and hazard analysis. The focus now is on having good characterisation of our exposure to MNPs and to rely on what we can possibly see in scenario studies. We will determine what data is required to be able to make decisions and what information is needed to develop a risk assessment strategy for MNPs.”