Modeling fate and transport of microplastics in riverine systems

Annual plastic production worldwide increased exponentially from 2 million tons in 1950 to 368 million in 2019. Such wide uses of plastic products have been considered as one of the primary environmental problems affecting the marine ecosystems across the world negatively. Rivers have been recognized as important pathways for transport and fate of microplastics into the oceans. It was estimated that between 1.15 and 2.41 million tonnes of plastic waste currently enters the ocean every year from rivers, with over 74% of emissions occurring between May and October. Simulations of fate and transport of microplastics in riverine systems were conducted through OpenFoam platform using ScalarTransportFoam Solver, taking into advection, diffusion, and aggregation and breakup processes. Our simulation results show a spatially varied concentration profile of microplastics originated from the source point with time. Significant amounts of particles aggregate along their transport. The study has strong implications on measurements and quantification of microplastics in river systems