Occurrence, distribution, and potential risks of ingested microplastic particles in three commercial fish species in...

This study investigated the abundance, characteristics, and potential ecological risks of microplastics in three commercially important fish species (Clarias gariepinus, Oreochromis niloticus, and Labeobarbus spp.) in Lake Tana, Ethiopia. Given the increasing anthropogenic pollution from surrounding urban activities and agricultural runoff, evaluating microplastic ingestion in aquatic biota is critical. Thirty-six fish (n = 12 per species) were collected, and their gastrointestinal tracts were analyzed using stereomicroscopy and an infrared spectrometer. Microplastics were detected in 69.5% of the total samples. The ingestion rates varied significantly among the species, with the omnivorous C. gariepinus showing the highest average contamination (4.92 ± 2.68 microplastics per fish), followed by the phytoplanktivorous O. niloticus (2.17 ± 1.99 microplastics per fish), and the herbivorous Labeobarbus spp.(0.17 ± 0.39 microplastics per fish). Fibers (61.8%) and fragments (36.0%) were the dominant shapes, while red (38.2%) and blue (29.2%) were the most frequently observed colors. Polymer analysis identified polyethylene (55%), polypropylene (27%), and polyethylene terephthalate (18%) as the primary types. The severe contamination observed in C. gariepinus and O. niloticus highlights significant ecological risks and potential human health implications. Targeted interventions, such as improved urban waste management and agricultural runoff control, are urgently needed to mitigate microplastic pollution in the Lake Tana ecosystem.