Transport dynamics of microplastics from land to sea: the role of particle properties and stream morphology.

Rivers and streams are the primary conduits through which microplastic pollution moves from land to sea. Attributes of the plastic and of the streams are both likely to influence how microplastic moves, but there are few empirical studies of plastic transport dynamics in real systems. We adapted the spiralling technique commonly used to measure nutrient cycling in streams to quantify transport distances and deposition velocities of microplastics in streams with varying geomorphological structure and level of human modification. We conducted pulse releases of trace amounts of three size classes of five different polymers spanning a density gradient in fifteen streams. The streams were typical of the range of human modification in urban environments, from semi-natural to highly modified. A range of geomorphological and hydrological parameters were quantified in each stream. Transport distances of microplastic ranged from Also see: https://micro2024.sciencesconf.org/558661/document