The Universitat de Girona (UdG) recently made a significant contribution to the 15th International Symposium on River Sedimentation (ISRS), held in Florence from September 5th to 8th, 2023. The ISRS, initiated by the Chinese Hydraulic Engineering Society (CHES) with the support of UNESCO, is a triennial event that provides a platform for the exchange of ideas, research findings, and advanced techniques in the study and management of sediments.

Mirco Mancini, a PhD student from the University of Florence currently conducting a research stay at UdG, presented his research titled "Suspended sediments open the way to microplastic sedimentation in shallow aquatic systems." This work, conducted in collaboration with Dr. Teresa Serra and Dr. Jordi Colomer from UdG’s Department of Physics, explores the interplay between suspended sediments and microplastics in shallow aquatic environments.

Background and Motivation

The study addresses the pressing issue of microplastic pollution, which poses a serious threat to marine and freshwater ecosystems. Shallow aquatic systems, such as floodplains and wetlands, are particularly prone to microplastic accumulation due to their low energy zones and stagnant waters. These environments facilitate the presence of suspended sediments, which play a crucial role in the transport and sedimentation of microplastics.

Experimental Approach

The experiments were conducted in a laboratory flume designed to simulate shallow water conditions. The setup included a platform to mimic a shallow zone and sediment traps to capture particles along the flume. The study investigated the behavior of three common types of microplastics: PVC fragments, PA fragments, and PET fibers, under varying sediment concentrations.

Findings and Implications

The results revealed that the transport of microplastics is significantly influenced by the type of microplastic and the presence of suspended sediments. Fast-settling sediment particles were found to scavenge microplastics, increasing their sedimentation rates. This led to a heterogeneous distribution of microplastics, with faster settling particles accumulating closer to their source, while slower settling particles traveled further, depending on the sediment concentration.

The research underscores the importance of considering suspended sediment concentration in models of microplastic transport in low-energy aquatic environments. The findings suggest that incorporating this factor can significantly improve the accuracy of mass balance models for plastic particles in these ecosystems.

The participation of UdG at ISRS 2023 highlights the institution's dedication to tackling environmental challenges through rigorous scientific research. The insights provided by Mirco Mancini and his colleagues contribute valuable knowledge to the field of microplastic pollution, aiding in the development of strategies to mitigate this growing environmental issue.

For more detailed information on this study, please refer to the article "Suspended sediments open the way to microplastic sedimentation in shallow aquatic systems" presented at ISRS 2023.