Microplastics were detected in each of the 160 fish specimens assessed. A total of 5,744 microplastics were counted, with a mean of approximately 40 items found per fish. Six types of microplastics were identified based on shapes: microbeads, fragments, burnt film, fibers, pellets, and thread. Microbeads occurred in all of the assessed fish guts, accounting for 43 percent of all microplastics found, followed by fragments (27 percent), burnt film (14 percent), thread (9 percent), fibers (4 percent), and pellets (3 percent).

Based on the size classes estimated for the study, the researchers believe that close to 15 percent of the microplastics found in the guts of the assessed fish have the potential to translocate through the fishes’ gut barriers into their muscles. The contaminated muscles are then ingested by humans, and may subsequently translocate to other human organ tissues.

The annual intake of microplastics from the consumption of whole fish by the adult population for each species was estimated as follows: M. cephalus (178,220), I. Africana (131,670), P. senegalensis (115,710), P. jubelini (109,060), S. maderensis (101,080), G. decadactylus (101,346), and S. melanotheron (65,170). Estimated annual intakes were generally higher for fish species with broad habitat and feeding preferences.