Assessment of Microplastic Contamination in Commercially Important Fish Species From the Old Brahmaputra River and Its Environmental Health Impact

ABSTRACT Microplastic (MP) pollution in freshwater ecosystems poses a significant threat to aquatic biodiversity, food safety, and public health. This study investigates MPs in four commonly consumed freshwater fish species, including Trichogaster fasciata, Mystus tengara, Ompok pabda , and Botia Dario , collected from the old Brahmaputra River in Bangladesh. MPs were found in the intestine of all fish samples and in 37.5% of the muscle tissues, with an average abundance of 5.37 ± 2.69 particles per individual. Thread‐like MPs were mainly found (67%), followed by fragments (13%), pellets (12%), and fibers (8%). Most of the extracted MPs were red and 1–5 mm in size. Fourier transform infrared spectroscopy identified several polymer types, including polyethylene, polypropylene, polyethylene terephthalate, polyamide‐6, polyvinyl chloride, and ethylene vinyl acetate, with polyethylene being the most common polymer detected. Pollution load index and contamination factor analyses reveal significant MP accumulation in fish tissues, highlighting ecological and human health concerns. The findings reveal high MP levels in fish, underscoring the need for collective efforts to protect the river's health for future generations.