Investigation of Microplastic Abundance from Commercial Marine Fish in Bintulu, Sarawak, Malaysia

The plastic pollution is an ever-growing issue across the globe. In particular, Microplastics (MPs) can act as toxin accumulators in the fish tissues, which may transfer to human bodies via food chain and potentially harmful to human health. In Malaysia, studies related to MPs mostly focused on sediment and wild-caught freshwater fish. However, there is a lack of study on commercial marine fish especially conducted in Bintulu, Sarawak, East Malaysia. Therefore, this study was to investigate and establish baseline data for future research and monitor of MPs pollution in Bintulu's marine environment. The MPs were observed in the gastrointestinal tracts (GITs) and gills from the 6 species of commercial marine fish. The sample was digested with 15% of KOH solution, with shaking at 90 rpm, at 60 °C for 24 h, then continued with shaking at 90 rpm at room temperature for 24 h. After that, the MPs sample were extracted by density separation using 100 mL NaCl solution. The samples were identified and characterized under stereomicroscope and Attenuated Total Reflection Fourier Transform Infrared spectroscopy (ATR-FTIR). As the result, the highest abundance was found in Alepes djedaba with an abundance of 3.51 $$\pm$$ 0.764 items/g, and the lowest abundance was found in Gerres filamentosus with an abundance of 1.48 $$\pm$$ 0.440 items/g. The most dominant shape, color and size of MPs across the study were fiber (73%), blue (47%) and less than 1 mm (67%), respectively. FTIR analysis detected polymer compositions of polystyrene (PS) and polyamide (PA) in the sample. This study provides baseline data on MPs research in Bintulu and becomes source of information for policy makers to take better actions.