The ‘plastics’ model simulates the river export of microplastics from land to coastal seas. If present in high concentrations, micro and macroplastics may pose a threat to the water quality of both coastal as well as freshwater systems. The modelling framework of the plastics model is based on the Global NEWS model, as the plastics model uses a similar approach for river basin export processes, point and diffuse sources of pollution, and future scenario analyses. The plastics model also simulates the effect of riverine retention and wastewater treatment on the removal of plastics from surface water.
At present, the plastics model has been implemented for point source inputs of microplastics to major river basins draining into European seas (based on the river basins used in Global NEWS). The simulations were performed for the years 2000 and 2050. Following the Global NEWS approach, the Millennium Ecosystem Assessment (MEA) scenarios were used to simulate future plastics export.
Current developments concerning the plastics model focus on expanding the spatial extent of the model to quantify river export of plastics on a global scale, and to also account for macroplastics. Furthermore, sewage and wastewater treatment management strategies may be explored to construct explicit customised future scenarios.