Longitudinal dispersion of microplastics in aquatic flows using fluorometric techniques

Microplastics are an emerging environmental contaminant. Existing knowledge on the precise transport processes involved in the movement of microplastics in natural water bodies is limited. Microplastic fate-transport models rely on numerical simulations with limited empirical data to support and validate these models. We adopted fluorometric principles to track the movement of both fluorescent dye and florescent stained microplastics (polyethylene) in purpose-built laboratory flumes with standard fibre-optic fluorometers. Neutrally buoyant microplastics behaved in the same manner as a solute (Rhodamine) and more importantly displayed classical fundamental dispersion theory in uniform open channel flow. This suggests Rhodamine, a fluorescent tracer, can be released into the natural environment with the potential to mimic microplastic movement in the water column.Published versionFunding was provided by the Natural Environmental ResearchCouncil (grant NE/R003645/1) and University of Warwick GlobalChallenges Research Catalyst Fund. We gratefully acknowledgeI.Baylis, our Civil Engineering technician, for help with the experi-mental set up and design and helpful discussions with colleaguesincluding J.A. Christie-Oleza (University of Warwick Life Sciences)