Influence of microplastics on freshwater bivalves (review)

Anthropogenic pollution of the aquatic environment with microplastics is one of the most urgent but least studied problems of modern ecotoxicology. The review, based on recent literature data, provides an analysis of studies in the field of absorption, bioaccumulation, and biological effects of microplastic exposure in freshwater bivalve molluscs (Bivalvia). A total of 22 studies have been conducted so far, which were performed on representatives of three families: Cyrenidae (45), Unionidae (25) and Dreissenidae (30%). The conducted studies are represented by field observations (43.5), field (8.7) and laboratory (47.8%) experiments. It has been shown that freshwater bivalves, as active filters, are able to absorb and accumulate in soft tissues (gills, hepatopancreas) microplastic particles from both water and bottom sediments, perceiving them as food objects. Bioaccumulation of microplastics in molluscs leads to functional and structural disorders in the body. The joint action of microplastics and other pollutants (cadmium, polychlorinated biphenyls, pharmacological drugs) can cause both synergistic and antagonistic effects in the biological responses of molluscs. Based on the conducted studies, it is suggested to use bivalve molluscs as organisms-bioindicators of freshwater pollution with microplastics.