The Occurrence of Microplastic Ingestion in Commercial Marine Fish in Miri, Sarawak, Malaysia

ABSTRACT Microplastics are polymer‐based particle compositions of various toxic chemicals with size less than 5 mm. Due to their small size, microplastics can be ingested and accumulate in body tissues of organisms. This raises concerns about their toxicity being transferred to humans via food consumption. However, there are still a limited number of studies on microplastic pollution, especially conducted in Miri, Sarawak, Malaysia. This study aims to determine the abundance and characteristics of microplastics in commercial marine fish in city of Miri, Sarawak, Malaysia. Microplastic ingestion was observed in the gastrointestinal tract of 22 individuals from three commercial marine fish species collected from three different local Miri fish markets. Five grams of dissected gastrointestinal tract was extracted with alkali digestion, followed by density separation and filtration. Then, the sample was identified by multi‐detection techniques such as stereomicroscope for quantification, and morphological analysis along with ATR‐FTIR for chemical characterization. The abundance of ingested microplastics was within the range of 47.03–367.24 items/kg. The highest microplastics concentration was observed in Indian mackerel, implying the potential indicator species. The identified particles had fiber morphology, predominantly polyester (PET) with fiber (73%), black color (48%), and a size range of <1 mm (59%). The observed polymer compositions observed were polystyrene (PS), PET fibers, silicon polymer, and polyamide (PA). Overall, this study established a pathway for utilizing marine fish as a biological indicator in monitoring marine pollution in Miri, Sarawak, Malaysia. This study also provides information to raise public awareness and to support policymakers and researchers in developing strategies to mitigate microplastic pollution, thus protecting both human health and marine environment.