Do different habits affect microplastics contents in organisms? A trait-based analysis on salt marsh species

Salt marshes in urban watersheds are prone to microplastics (MP) pollution due to their hydrological characteristics and exposure to urban runoff, but little is known about MP distributions in species from these habitats. In the current study, MP occurrence was determined in six benthic invertebrate species from salt marshes along the North Adriatic lagoons (Italy) and the Schelde estuary (Netherlands). The species represented different feeding modes and sediment localisation. 96% of the analysed specimens (330) did not contain any MP, which was consistent across different regions and sites. Suspension and facultative deposit-feeding bivalves exhibited a lower MP occurrence (0.5-3%) relative to omnivores (95%) but contained a much more variable distribution of MP sizes, shapes and polymers. The study provides indications that MP physicochemical properties and species' ecological traits could all influence MP exposure, uptake and retention in benthic organisms inhabiting European salt marsh ecosystems.