Screening for microplastics in sediment, water, marine invertebrates and fish: Method development and microplastic accumulation

Measurements of microplastics in biota and abiotic matrices are key elements of exposure and risk assessments for this emerging environmental pollutant. We investigated the abundance of microplastics in field-collected biota, sediment and water. An improved sediment extraction method, based on density separation was developed. For analysis of microplastics in biota we found that an adapted enzymatic digestion protocol using proteinase K performed best, with a 97% recovery of spiked plastic particles and no observed degradation effects on the plastics in subsequent Raman analysis. Field analysis revealed that 8 of 9 tested invertebrate species from the North Sea and 68% of analyzed individuals of brown trout (Salmo trutta) from the Swedish West Coast had microplastics in them. Based on the number of plastic particles per kg d.w. the microplastic concentrations found in mussels were approximately a thousand-fold higher compared to those in sediment and surface water samples from the same location. [Display omitted] •Recovery of microplastics (MPs) from sediment was improved with olive oil.•Enzymatic digestion for MPs in biota gave a 97% recovery of spiked particles.•MPs were found in 8/9 invertebrate species on the North Sea coast.•MPs were found in 68% of stomach samples of S. trutta from the Swedish west coast.•Mussels had much higher levels of MPs compared to surrounding water and sediment.