The abundance and characteristics of microplastics in different organs of both wild and farmed milkfish (Chanos chanos) from Madura, Indonesia

Microplastics (MPs), represent a significant global issue that endangers aquatic ecosystems. This study aims to analyze the abundance, physical characteristics (shape, color, and size), and types of polymers and chemical compounds in gills, stomach and intestines of milkfish from marine waters and ponds from Madura Indonesia. The Kruskal-Wallis test showed that MPs in milkfish gills and water from all of the locations were not statistically different, but MPs in the stomach and intestine differed. The Mann-Whitney test showed that milkfish from Camplong pond (PCM) had the most MPs in the stomach and intestine, while milkfish from Jrengik (PJM) pond and Camplong coastal water (CWM) had no significant difference. The fiber-shape MPs were the most abundant in all organs of milkfish and water. The black MPs were the most prevalent among all milkfish organs. The MPs measuring less than 500 µm were most abundant in milkfish organs and water across all locations. The increase in MPs abundance in aquatic environments was associated with higher concentrations of MPs in organs. The Spearman correlation test revealed no correlation between the abundance of MPs in milkfish organs and the length of milkfish across all locations. Seven MPs polymers were identified in various organs of milkfish and water: polyvinyl chloride, polystyrene, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene, and ethylene-vinyl acetate. The analysis of the gills, stomach and intestines of milkfish using gas chromatography-mass spectrometry identified the presence of plasticizers, stabilizers, lubricants, release agents, and various additives, such as octadecanoic acid, 1-hexadecanol, oleic acid, eicosane, and hexadecanoic acid.