 Microplastic contamination has been detected in both sediments and floating waters of northwest Europe. The concentration of microplastics in sediments ranges from 0 to 3146 particles per kilogram of dry weight sediment, while floating waters range from 0 to 1.5 particles per cubic meter. Estuaries and areas with higher organic carbon content appear to be hot spots for microplastic contamination. To accurately measure microplastic levels, it is important to standardize sampling methods across regions so that comparisons can be made over time. This article was authored by Thomas Mays, Thomas Mays, Myra D. van der Meulen, and others.