Extraction and characterization of microplastics in seafood: Identification of a suitable protocol and application to field study

International audienceMarine litter consists in 60 to 80% of plastics including microplastics, usually defined as particles with a size below 5 mm. Microplastics now constitute a major worldwide concern with physical and chemical threats relative to adsorbed persistent organic pollutants or plastic additives such as flame retardant, bisphenol A or phthalates.To date, international bodies recommend using standardized, effective and cost efficient analytical methods since microplastics studies implies sampling a large number of individuals. Nonetheless, protocols currently dedicated to microplastics isolation are still facing limits as polymer degradation or huge dwell times. The purpose of this work was to benchmark six existing protocols regarding their impact on polymers and their efficiently dissolving organic matter. A first step allowed selecting and slightly modifying the three most promising protocols after tests on six of the most produced plastics in the world. These three protocols were then applied to 15 different polymers and their impacts were assessed based on weighing, microscopic observations, identification by pyrolysis coupled with GC/MS (Pyr-GC/MS) and Raman microspectrometry. Selection of suitable protocols, i.e. with no incidence on polymers, was performed by comparison of the results obtained before and after application of digestion methods. Finally, a single protocol was retained after tests performed on seafood tissues, consisting in evaluation of digestion efficiencies and spiking tests.A field study was launched to assess the prevalence of microplastics in seafood products highly consumed in France. To this end, three species of fish (common sole, mackerel, black seabream) and two species of shellfish (mussels and cockles) were sampled to monitor their level of microplastic contamination.Based on this study, the selected protocol could now be proposed as an efficient, and cost effective isolation process of microplastics from seafood tissues