Modeling three-dimensional microplastic transport and sedimentation in lakes and reservoirs

Presence of microplastic (MP) particles poses possible risks to lentic ecosystems. To quantify the exposure of organisms to MP contamination, it is crucial to identify patterns of MP transport, residence time and sedimentation in lakes and reservoirs. We utilize the Delft3D Flexible Mesh Suite to set up a three-dimensional hydrodynamic and MP transport model employing a reservoir in southern Germany as a test domain. The initial and boundary conditions for the hydrodynamic model as well as the calibration and validation datasets rely on measurements. We implement the MP transport via an Eulerian approach in order to efficiently simulate large concentrations of particles. By performing a range of simulations for different polymer types and MP sizes we investigate the influence of different particle properties on the transport and sedimentation behavior. Our simulation results for various particle types indicate that both, the particle density and size strongly affect transport and sedimentation patterns. While larger particles and those with a higher density settle in a limited area near the entry point, smaller particles with low density remain suspended for long time periods and spread over the whole extent of the reservoir. Also see: https://micro2024.sciencesconf.org/558915/document