Microplastic contamination in branded and non-branded edible Soybean oil from Bangladesh

This study provides the first evidence from Bangladesh on the occurrence, characteristics, and potential health risks of microplastics (MPs) in both branded and non-branded soybean oils marketed in Bangladesh. A total of 60 randomly collected samples were analyzed using solvent dilution, stereomicroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The mean MP abundance was 53,922 ± 10,510 particles/L, with significantly higher levels in non-branded oils (59,778 ± 11,648 particles/L) compared to branded oils (48,067 ± 4,683 particles/L) (p < 0.05). Fibers predominated (82.50%), with particles sized 101–500 µm being most abundant (35.84%). Transparent MPs were the most frequent (56.29%). FTIR identified six polymer types: Low-Density Polyethylene (LDPE), Low-Density Polyethylene (HDPE), Polypropylene (PP), Polyethylene Terephthalate (PETE), Polyurethane (PU), and nylon, with PU and nylon reported for the first time in edible oils. Principal component analysis indicated broader contamination sources in branded oils, linked to processing and packaging, whereas non-branded oils showed concentrated contamination from coarse particulates. Health risk assessment estimated an Estimated Daily Intake (EDI) of 17.65 MPs/day (adults) and 77.21 MPs/day (children), an Estimated Annual Intake (EAI) of 6,441.24 MPs/year (adults) and 28,180.45 MPs/year (children), and Lifetime MP Exposure (LME) of 4.77×10⁵ MPs (adults) and 2.09×10⁶ MPs (children). The MP Contamination Factor (MPCF) and MP Load Index (MPPLI) indicated moderate contamination and low pollution risk, respectively, underscoring stricter monitoring of edible oils in Bangladesh to prevent future contamination possibilities.