Assessing the relationship between the abundance and properties of microplastics in water and in mussels

Microplastic pollution is increasingly becoming a great environmental concern worldwide. Microplastics have been found in many marine organisms as a result of increasing plastic pollution within marine environments. However, the relationship between micoplastics in organisms and their living environment is still relatively poorly understood. In the present study, we investigated microplastic pollution in the water and themussels (Mytilus edulis, Perna viridis) at 25 sites along the coastal waters of China. Wealso, for the first time, conducted an exposure experiment in parallel on the same site using M. edulis in the laboratory. A strong positive linear relationship was found between microplastic levels in thewater and in the mussels. Fiberswere the dominantmicroplastics. The sizes ofmicroplastics in themussels were smaller than those in the water. During exposure experiments, the abundance of microbeads was significantly higher than that of fibers, even though the nominal abundance of fiberswas eight times that ofmicrobeads. In general, our results supported positive and quantitative correlations ofmicroplastics in mussels and in their surroundingwaters and that mussels were more likely to ingest smaller microplastics. Laboratory exposure experiment is a good way to understand the relative impacts of microplastics ingested by marine organisms. However, significant differences in the results between exposure experiments and field investigations indicated that further efforts are needed to simulate the diverse environmentally relevant properties of microplastics. (C) 2017 Elsevier B.V. All rights reserved.