The 15th International Symposium on River Sedimentation (ISRS) took place in Florence from September 5-8, 2023. This triennial event, initiated by the Chinese Hydraulic Engineering Society (CHES) with UNESCO's support in 1980, provides a platform for scientists, engineers, researchers, and decision-makers to exchange ideas, research findings, and advanced techniques regarding the study and management of sediments. This year, researchers from the Universitat de Girona participated to present their work within the PlastikHum project, focusing on the transport and sedimentation of microplastics in aquatic environments.

Gravity Currents as a Pathway to Segregate Transport of Microplastics

Dr. Marianna Soler presented her study on the role of gravity currents in the transport and segregation of microplastics. The research involved experiments in a methacrylate flume to simulate turbidity currents, which are underwater currents driven by the weight of sediment-laden water. Dr. Soler et al. found that microplastics are distributed and deposited at varying distances based on their densities and settling velocities, indicating that gravity currents can effectively segregate microplastics by type during transport. This segregation enhances our understanding of microplastic deposition patterns in aquatic ecosystems and emphasizes the need for targeted plastic pollution mitigation strategies​​.

Suspended Sediments Open the Way to Microplastic Sedimentation in Shallow Aquatic Systems

Mr. Mirco Mancini, a PhD student from the Università Degli Studi Di Firenze conducting research at the University of Girona, explored the interaction between suspended sediments and microplastics in shallow aquatic environments. His experiments demonstrated that suspended sediments can significantly enhance the sedimentation rates of microplastics. The presence of fast-settling sediment particles accelerates the deposition of microplastics, which otherwise might remain suspended and travel further. This finding is crucial for developing models to predict microplastic distribution and for devising effective management practices to reduce plastic pollution in low-energy aquatic systems​​.

Microplastic Retention by Lagoons Surrounded by Vegetation in Wetland Areas

Dr. Teresa Serra presented her research on the retention of microplastics by vegetated lagoons in wetland areas. Using a laboratory flume setup, Dr. Serra investigated how the presence and length of vegetation patches surrounding a lagoon influence microplastic sedimentation. The study revealed that lagoons with surrounding vegetation patches, particularly those longer than 5 times the water height, are more effective at trapping microplastics, thereby protecting the lagoon from contamination. This highlights the importance of vegetation in wetland ecosystems for mitigating the impact of microplastic pollution​​.

These presentations underscore the significant contributions of Universitat de Girona researchers in understanding and mitigating microplastic pollution in aquatic environments, aligning with the goals of the PlastikHum project.