Occurrence of microplastics in commercial fish from a natural estuarine environment

Abstract Microplastic ingestion has been reported for several marine species, but the level of contamination in transitional systems and associated biota is less known . The aim of this study was to assess the occurrence of microplastic ingestion in three commercial fish species: the sea bass ( Dicentrarchus labrax ), the seabream ( Diplodus vulgaris ) and the flounder ( Platichthys flesus ) from the Mondego estuary (Portugal). Microplastics were extracted from the gastrointestinal tract of 120 individuals by visual inspection and digestion solution. A total of 157 particles were extracted from 38% of total fish (96% fibers), with 1.67 ± 0.27 (SD) microplastics per fish. Significantly higher amount of ingested microplastics was recorded for D. vulgaris (73%). The dominant polymers identified by μ-FTIR were polyester, polypropylene and rayon (semi-synthetic fiber). It is reported for the first time the presence of this pollutant in fish populations from the Mondego estuary raising concerns on their potential negative effects.