Occurrence and Assessment of Human Exposure to Microplastic Particles in Bottled Water From Southwest, Nigeria

Background: The investigation of microplastics (MPs) in different environmental media is well documented; however, the prevalence and possible human health risks of MPs in bottled water are not fully understood. Methods: This study was designed to (a) determine the quantity, form, color, and size of MPs, (b) evaluate the influence of physicochemical properties on the release of MPs in bottled water, and (c) estimate the daily intake (EDI) of MPs in eight distinct varieties of bottled water from Southwest Nigeria. The Rose Bengal staining method and microscopic analysis were employed to identify, quantify, and characterize the MPs. Results: The bottled water brands from Southwest Nigeria contained MPs of various shapes, colors, and sizes. The average abundance of MPs was 15.2±2.9 particles/L, with the highest abundance being 21.3±1.8 particles/L. Fibers (82%) were the most detected shape of MPs, followed by fragments (18%), with transparent and blue being the two colors observed. Particle sizes ranged from 0.2 to 2.5 mm. The concentrations of MPs in the bottled water were strongly correlated (r=0.789, P<0.01) with the pH of the water samples. Adults had an estimated EDI of 0.31 to 0.66 particles/kg bw/day, while children’s EDI ranged from 1.13 to 2.36 particles/kg bw/day. Conclusion: These findings provide insights for scientists to better understand the contamination of bottled water by MPs and help regulatory bodies formulate appropriate regulations for the production and bottling of drinking water.