Final Report Summary - MARMICROTOX (Marine microplastics toxicity: investigating microplastics and their co-contaminants in marine organisms) One of the most prominent and ubiquitous anthropogenic changes in the marine environment has been the accumulation of plastic debris throughout the oceans. The physicochemical properties of plastics, extensive use in products and indiscriminate disposal are the key factors that contribute to the permanence and abundance of plastics in marine environments. Larger pieces of plastic ultimately fragment into smaller particulates, and plastics are also manufactured as small particles or fibres that are eventually released into the environment. Microplastics (MPs) are particles between 5 mm and 1 µm, and are reported as the most abundant pieces of plastics found in the marine environment. These particles accumulate at the sea surface on shorelines and in sediments and can be found in remote areas, far from their original source.Microplastics are ingested by organisms and the prominent concerns of this exposure include physical disruption of tissue surfaces, negative effects on digestive system processes, absorption across epithelial membranes and accumulation in internal tissues, trophic transfer in the food web and increasing the bioavailability of toxic substances (co-contaminants) that may be associated with microplastics. The goal of this project, MARMICROTOX, was to assess abundance and type of microplastics in wild mussels collected from sites on the coast of Scotland, as well as to conduct laboratory studies to investigate 1) effects of microplastics uptake in mussels in gills and digestive gland tissue, 2) assess pathophysiological effects in fish and 3) understand whether co-contaminants sorbed to microplastics are bioavailability to mussels and fish.This project has contributed to an advance in the understanding of microplastic effects in aquatic organisms. Our data indicates that particles are present at very low levels in wild mussels and in mussels placed in cages deployed at various locations in Scotland. Co-contaminants (cadmium and Benzo(a)pyrene) sorbed to MPs were bioavailable to mussels via ingestion, but only at high plastic particle concentrations. Rainbow trout ingested MPs and there were no gross indications of distress in fish exposed to MPs or MPs with sorbed triclosan (a bactericide present in toiletry products). Analyses of the effects of MPs and triclosan on fish gut microbiota and immune system function are nearing completion. Our data represents an important step into the assessment and analysis of MPs contamination levels and effects, leading to a better understanding of possible ecological risks.For more information, please see:Dr. Ana Catarino: epaquatic.org/ana-catarino-hwu
