Occurrence and exposure analysis of microplastic in the gut and muscle tissue of riverine fish in Kermanshah province of Iran

Highlights: • Microplastics (MPs) have been determined in tissues of fish from the Qarasu River in Kermanashah province. • MPs of mainly fiber and fragment nature were detected in all tissues and species examined. • Mean abundance ranged was higher in stomach contains than muscle in all specious. • The mechanism by which MPs enter muscle tissues is unclear. • The MPs contamination of seafood raises a concern for human consumption. This study aimed to determine the presence of MPs in the gut and muscle tissue of riverine fish collected from the Qarasu River, Kermanshah, Iran. The results highlighted that MPs were found in the gut and muscle of all fish species at an average abundance of 8.12 ± 4.26 P/individual and 0.85 ± 0.38 P/g muscles, respectively. High amounts of MPs were found in the range of 1-25 μm in terms of size distribution. The properties of MPs extracted indicated that PE, PP, PS, and PA in the monotype of fiber and fragment were the most abundant plastic types and shapes found. Additionally, EAI was calculated for MPs found in the muscle. So, 174.43 and 127.19 P/kg/bw/year (1.28 and 0.93 g/kg/bw/year), were intake by two groups of adults and children, respectively. These findings highlight the contamination of fish as a common source of marine food in home consumption and the probability of entrance into the human diet.