Sub-Basin Scale Heterogeneity in the Polymeric Composition of Floating Microplastics in the Mediterranean Sea

Here, we present the results of a large-scale survey of floating microplastics (<5 mm) and meso-plastics (5-20 mm) in central-western Mediterranean waters, providing the largest polymeric characterization ever performed (n = 4050 parti- cles). We confirm the Mediterranean Sea as severely contaminated by plastic pollution and describe for the first time the complex mixture of synthetic polymers floating on its surface, testing the hypothesis that plastic distribution and compo- sition are not homogeneous and that geographical differences exist between sub-basins.