Microplastics in freshwater
About the talk
Recent research on the impacts of microplastics (MPs) in freshwater ecosystems appears contradictory, due to complex interactions between aquatic habitats, MPs, and aquatic organisms; and to a lack of standardization of MPs sampling and analysis. Understanding how microplastics are transported and distributed along river systems is key to assessing the ecosystem impacts, and modelling the main hydraulic, mixing, sedimentation and resuspension processes. We use a new microplastics model for the River Thames based on the process-based dynamic (daily) Integrated Catchments (INCA) model. Recent evidence from UK water industry studies on microplastics in effluent discharges and sewage sludge disposal has been utilised to drive the INCA Microplastics model. Predicted concentrations, loads and dynamics along the river system are shown to be significant, with a build-up on riverbeds and sediments. The potential impacts on aquatic ecosystems are evaluated and a review of MP mitigation legislation and policy is considered. We use the INCA model to evaluate alternative strategies for microplastics control using, for example, effluent treatment reductions, reduced applications or loads of sewage sludge applied to land, and evaluating potential improvement via policy. The critical gap in standardisation of methods is further discussed in relation to monitoring effective policy instruments.
We welcome Prof. Paul Whitehead, Dr. Jocelyne Hughes