I recently had the opportunity to attend and present at the European Geosciences Union (EGU) General Assembly 2026 in Vienna. My participation was primarily focused on Session HS8.1.8, an excellent interdisciplinary forum that brought together leading researchers investigating the hydrodynamic drivers, biogeochemical interactions, and transport mechanisms of microplastics across various environmental compartments.
I delivered an oral presentation titled "Plasma-treated polystyrene microplastics for enhanced transport studies in porous media: A surfactant-free approach." My talk addressed a critical methodological challenge in our field: the reliance on surfactants to stabilize hydrophobic microplastics in aqueous solutions during laboratory experiments, which inadvertently alters the surface chemistry and transport behavior of the particles in soils and groundwater. I presented our novel surfactant-free approach using plasma treatment to modify the surface of polystyrene microplastics. I demonstrated how this method successfully mimics natural environmental weathering and oxygenation while allowing for highly accurate, artifact-free transport studies in saturated porous media. The presentation was well-received, sparking a productive discussion during the Q&A about the scalability of plasma treatment and its potential to become a standard protocol for future groundwater modeling.
The oral and poster sessions provided profound insights into the complex physical and biological dynamics governing microplastic transport, transitioning my perspective from isolated environments to interconnected systems. A major takeaway was how environmental variables drastically alter transport pathways; for instance, high suspended sediment concentrations can turn rivers from passive conveyors into temporary sinks by driving fiber deposition, while estuarine haloclines create density barriers that significantly reduce settling velocities. Furthermore, advanced modeling of the "missing plastic" paradox revealed that biofouling induces complex, oscillatory vertical migrations of particles in the ocean, highlighting that particle characteristics like shape and density fundamentally dictate their long-term fate. Crucially, exploring related research on nanoplastic mobility in mineral-coated media and retention at the river-groundwater interface strongly reinforced the necessity of my own surfactant-free experimental approach.
Beyond the formal sessions, the conference provided a fantastic platform for networking. I had the chance to discuss potential collaborations with researchers, exchanging ideas on how to apply our plasma-treatment method to their specific soil models. Moving forward, the insights gained from this conference will directly inform the design of my upcoming porous media experiments.
Finally, I would like to express my sincere gratitude to the Graduate School of Geosciences (GSGS) for their generous financial support. Their funding made it possible for me to attend this premier global geosciences event, share my research with the international scientific community, and build invaluable academic connections that will undoubtedly benefit the remainder of my PhD journey.
Yifan Lu
PhD Student
Institute of Geography
Presentation title (Oral): Plasma-treated polystyrene microplastics for enhanced transport studies in porous media: A surfactant-free approach