Small microplastics and other components of microlitter in Arctic invertebrates (Amphipods)

Microplastics larger than 100 μm have been more studied than small microplastics (SMPs,< 100 μm). Due to their size, SMPs and other microlitter components (MLCs, e.g., plastic additives, natural and non-plastic fibres) can be carried further away from the release sources by atmospheric and marine currents. Plastic additives are mixed with plastic polymers to form plastic objects; they can be leached into the environment during their breakup. As fragments, SMPs and MCLs can be easily ingested by organisms and enter the trophic web. This study mainly focused on the identification of potential bioindicators of plastic pollution; to do so, the environmental load of SMPs and MCLs (quantification and identification) in organisms belonging to Arctic species of Amphipods (Crustacea) was evaluated. Some of the genres analyzed are cosmopolitan, and they can potentially be employed as bioindicators of plastic pollution around the globe. In the summer of 2022, specimens of Amphipoda were sampled in the coastal waters of Kongsfjorden, located on Spitsbergen Island, North-West of the Svalbard Archipelago. MPs and MLCs were extracted and then analyzed via Micro-FTIR (quantification and simultaneous characterization). All the operations of the pretreatment were performed in a clean room to minimize plastic contamination. The procedure does not use elevated temperatures or strong reagents that can destroy the particles. A wide variety of polymers and additives were observed; sizes, shapes and abundances were evaluated. Most of these particles are smaller than 100 μm. This confirms that the invertebrates and other organisms can ingest these particles. The load of SMPs and MCLs in invertebrates, predated by organisms in the upper layers of the food web, may enhance their biomagnification. Further results will also tell us more about the release hotspots for these contaminants and the influence of local and long-range transport.∗