Buoyant microplastics in freshwater sediments - How do they get there? - Molazadeh, Marziye (Aalborg Universitet. Department of the Built Environment) ; Simon-Sánchez, Laura (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals) ; Liu, Fan (Aalborg Universitet. Department of the Built Environment) ; Vollersten, Jes (Aalborg Universitet. Department of the Built Environment)