Microplastics in freshwater wild and farmed fish species of Bangladesh

In today's world, microplastic contamination of aquatic systems is a subject of major concern. In this study, the incidence of microplastics in freshwater fish from both farmed and wild sources was evaluated. Wild catla (Gibelion catla), stinging catfish (Heteropneustes fossilis), rui (Labeo rohita), tengara catfish (Mystus tengara), and pabdah catfish (Ompok pabda) were collected from Padma River, Turag River, and Bhairab River. Farmed fishes of same species were collected from Mymensingh and Chandpur fish markets. A total of 68 (43.6%) microparticles out of 156 were identified as microplastics using ATR-FTIR. About 66.67% (20 out of 30) of farmed fish samples had microplastics in their digestive system, while 88.4% (23 of 26) of wild fish samples presented microplastics. There was a significant difference (p < 0.05) in average microplastic count between wild and farmed fish. Average microplastic count also showed a significant difference among five fish species (p < 0.01). A variety of polymers were observed, with polyethylene being the most abundant, followed by polyester, polypropylene, polyamide-6, and polyurethane. This study suggests that microplastic contamination is ubiquitous and contamination is common in all of the fish species investigated, independent of their origin (wild or farmed). However, wild fish population is at a greater risk of ingesting microplastics. This study, for the first time ever, reports plastic pollution in freshwater fishes of Bangladesh from wild and farmed sources.