Edgar Hernandez,† Bernd Nowack,† and Denise M. Mitrano*,†,‡ †Empa, Swiss Federal Laboratories for Materials Science and Technology, Technology and Society Laboratory, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland ‡Eawag, Swiss Federal Institute for Aquatic Science and Technology, Process Engineering, Überlandstrasse 133, 8600 Dübendorf, Switzerland ABSTRACT Microplastic fibers make up a large proportion of microplastics found…