The city of Lausanne, Switzerland, in collaboration with the University of Geneva (UNIGE), is actively monitoring microplastic contamination in both the raw water sourced from Lake Geneva and the treated drinking water supplied to residents. Recent initial analyses reveal the presence of 10 to 40 microplastic particles per cubic meter (1000 liters) in the water after treatment. This proactive monitoring program highlights growing concerns about microplastic pollution in freshwater sources and its potential impact on public health.
Detailed analyses of water samples taken from depths supplying the Lutry and Saint-Sulpice water treatment plants indicate that the untreated Lake Geneva water contains significantly higher concentrations of microplastics, ranging from 260 to 950 microplastic particles per cubic meter. However, the city reports that these concentrations are dramatically reduced – by approximately 95% on average – through the water treatment process, resulting in the 10-40 MP/m3 levels detected in the distributed drinking water. This substantial reduction demonstrates the effectiveness of current water purification technologies in removing a significant portion of these particles.
The monitoring program, initiated on , is being bolstered by the upcoming inauguration of a new, dedicated microplastics laboratory within the Lausanne Water Department. This laboratory will be equipped with state-of-the-art technology, including direct laser infrared imaging (LDIR), enabling researchers to accurately detect, characterize and quantify microplastic particles. Pierre-Antoine Hildbrand, a municipal official overseeing water management, stated that this new facility represents a first for Lausanne and for a water distributor in the region, and will ensure continuous and rigorous scientific monitoring.
The current phase of the study focuses on microplastics measuring between 20 micrometers (0.02 mm) and 5 millimeters (5 mm) in both raw and treated water. A second phase of analysis is scheduled to begin in , suggesting a long-term commitment to understanding and addressing this emerging environmental challenge.
Understanding Microplastic Pollution in Lake Geneva
The presence of microplastics in Lake Geneva is not a new concern. A study conducted in 2018 estimated an annual input of 50 tonnes of plastic into the lake. However, more recent research, completed in 2024, indicates that this figure has doubled to 100 tonnes per year. This increase underscores the escalating problem of plastic pollution and the need for more comprehensive monitoring and mitigation strategies. The consultancy firm Earth Action, commissioned by the Association pour la Sauvegarde du Léman (ASL), conducted the 2024 study, titled Léman Plastic Action.
The sources of these microplastics are diverse, ranging from the breakdown of larger plastic items through abrasion and weathering to direct contamination and accidental leakage. The study identifies water runoff on permeable soils as the primary pathway for microplastics, accounting for 83% of the total. Notably, the automotive sector is identified as the largest single source, contributing approximately 33% of the microplastic load, primarily through tire abrasion. This highlights the often-overlooked contribution of microplastic particles released during normal vehicle operation.
The Broader Context of Microplastic Contamination
The issue of microplastic contamination extends far beyond Lake Geneva. Microplastics are increasingly detected in aquatic environments globally, raising concerns about their persistence, mobility, and potential risks to both ecosystems and human health. While the precise health effects of ingesting microplastics are still under investigation, research suggests potential for physical irritation, chemical leaching, and the absorption of harmful pollutants that adhere to the plastic surfaces.
The UNECE (United Nations Economic Commission for Europe) is actively addressing the issue of microplastic pollution in transboundary water basins, including Lake Geneva, through initiatives aimed at fostering international cooperation and developing effective pollution control measures. The Convention sur la protection et l’utilisation des cours d’eau transfrontières et des lacs internationaux provides a framework for collaborative efforts to protect shared water resources.
Implications for Drinking Water Safety
The findings from Lausanne’s monitoring program are reassuring in that the water treatment processes are demonstrably effective at removing a substantial proportion of microplastics. However, the presence of even low concentrations of microplastics in drinking water raises legitimate questions about long-term exposure and potential health effects. The city’s investment in advanced monitoring technology and research, such as the new LDIR laboratory, demonstrates a commitment to proactively addressing these concerns.
The ability to accurately detect and characterize microplastics is crucial for understanding the types of plastics present, their sources, and their potential impact. The LDIR technology will allow researchers to go beyond simply counting particles and delve into their composition and properties, providing valuable insights for developing more targeted and effective mitigation strategies. Further research is needed to fully assess the long-term health implications of microplastic exposure and to optimize water treatment processes for maximum removal efficiency.
The ongoing collaboration between the City of Lausanne and the University of Geneva is a model for other communities facing similar challenges. By combining municipal resources with academic expertise, they are building a robust scientific foundation for informed decision-making and effective environmental stewardship. The continued monitoring and analysis of microplastic levels in Lake Geneva will be essential for protecting this vital water resource and ensuring the safety of the drinking water supply for generations to come.
