Microplastics exposure in European flat oyster, Ostrea edulis: Evaluation of accumulation and depuration under controlled conditions and molecular assessment of a set of reference genes

Marine plastic waste is increasing dramatically, making this pollution one of the most serious environmental threats of recent decades. Plastic degrades and breaks down into smaller fragments, i.e. microplastics (MPs), bioavailable to a wide range of organisms. In particular, filter-feeding organisms are exposed to MPs through ingestion, so that bivalves are widely used as models to evaluate MPs environmental contamination. This research had two objectives: a) analyze bioaccumulation and depuration capacities of Ostrea edulis exposed to microplastics, b) identify a "robust" set of reference genes to assess bivalves' response to stress induced by microplastics pollutants. The experimental protocol unfolded in two phases: a 28 days exposure of specimens to MPs followed by a 7-days depuration period. During the first phase, individuals were exposed to a daily concentration of 10^4 MPs/L particles, previously subjected aged. Additionally, four weekly samples were collected for gene expression analysis. During depuration phase, every 24 hours, an oyster was collected and digested in hydrogen peroxide, filtrated, dried and analysed under stereomicroscope. After 28 days of exposure, the mean concentration of accumulated MPs stood at 5.31±0.86 particles/g distributed as follows: filaments 79 Also see: https://micro2024.sciencesconf.org/557519/document