The aim of the PLASTFLOW project is to assess litter accumulation in the Scheldt estuary, as well as to estimate the plastic flux and identify retention hotspots. The specific objectives of the project are to: Estimate the plastic flux from the Scheldt to the sea, followed by an evaluation of the flux using the t0 measurement, model the fate and accumulation of macro-, meso- and microlitter and pellets in the Scheldt estuary, taking into account the asymmetrical tidal retention of litter and to inform key stakeholders and policymakers.