by Javier Feller, Jonathan Osaigbovo Andura, Michelle Bodei, Sarina Sägesser, Andrin Müller
Invisible yet persistent, PFAS have become a growing concern for drinking water quality in the canton of Zurich. Per- and polyfluoroalkyl substances comprise a group of roughly 10,000 synthetic chemicals widely used for their repellent properties. Their extreme chemical stability makes them useful in everyday products and industrial applications—but also means they hardly degrade. As a result, PFAS accumulate in soils, groundwater, and ultimately the human body. They are also suspected to cause serious health effects such as cancer, hormonal disruption, and elevated cholesterol levels.
In Switzerland, groundwater is the most important source of drinking water, making PFAS contamination particularly relevant. Current legal thresholds for PFAS in drinking water are set to become stricter in 2026, when the maximum concentration for the sum of 20 selected PFAS (PFAS20) will be lowered to 0.1 µg/l. Alongside PFAS20, special attention must be given to trifluoroacetic acid (TFA), a highly mobile and persistent degradation product of other PFAS that however has no legal threshold.
Our blog focuses on how PFAS enter the environment and how their concentrations are distributed across municipalities in the canton. We find that hotspots tend to coincide with areas of intensive agriculture or nearby landfills. However several uncertainties remain. Groundwater flows ignore municipal borders, sampling points are unevenly distributed, and PFAS persist long enough to blur distinctions between sources. Such complexities make the issue all the more compelling. What do these «invisible» chemicals mean for the future of drinking water—and how can policies and technologies respond? To take a deep dive into the topic, check out the blog we produced in the context of the Geography. Matters. module at the Department of Geography in the fall semester of 2025.
PFAS IN OUR DRINKING WATER
About GEO410
This blog post is part of the outcome of an interdisciplinary Master’s-level course in Geography: GEO410 Geography. Matters. The course aims to bring together diverse geographic research perspectives to engage with some of the most pressing societal and environmental challenges of our time. As the only compulsory module of the Geography MSc program, the course encourages students to think across sub-disciplines of geography and to explore how geographic research can meaningfully contribute to debates around sustainability, justice, and environmental change.
Beyond conducting interdisciplinary research as a team, a central aim of the course was to experiment with creative and accessible forms of science communication. Rather than producing a purely academic output, students translated their research insights into blogposts, intended for a wider, non-specialist audience. The contributions thus showcase not only rigorous scientific work by highly motivated students, but also the importance of communicating research beyond the university and engaging broader publics in conversations about geography, sustainability and the future of our shared environments.
The students in the course GEO410 were supervised by Andreas Vieli, Christian Berndt and Sofia van Moorsel as lecturers and by Nikolas Klaudy as teaching assistant.
Beitragsbild: All images from pixabay.com, collage by blog post authors