Occurrence of microplastic particles in the most popular Iranian bottled mineral water brands and an assessment of human exposure

Microplastics (MPs) have recently been detected in different products and environmental samples, ranging from wastewater to drinking water, as well as in products consumed by humans. However, few studies have addressed the contamination by MPs in bottled mineral water. Therefore, in the present study, the contamination by MPs was investigated from 11 samples of popular brands of bottled mineral water in Iran. Using a staining method and stereomicroscope analysis, MPs were detected in 9 out of the 11 sample brands. The amount, shape, and color of MPs varied in different bottles. The most detected MPs were in the shape of fragment (93 %) and fiber (7%), with an average concentration of approximately 8.5 +/- 10.2 particles/L. In addition, there were no MPs in 20 % of the collected samples, which was the reason for the observed high variation of SD. The presence of MPs was demonstrated by FTIR and Raman stereoscopy and the most likely polymers found were PET, PS, and PP. Finally, four scenarios were investigated for daily and annual human exposure to microplastics. The study results indicate that the human daily and annual intake were negligible when compared using Valmet textures; approximately 0.015 P/kg/bw/day and 5.35 P/kg/bw/year for adults and approximately 0.065 P/kg/bw/day and 23.43 P/kg/bw/year for children.

Automated summary

Microplastics have been detected in popular brands of bottled mineral water in Iran, with fragment and fiber shapes being the most common. The average concentration of MP particles was approximately 8.5 particles/L. While most samples contained MPs, 20% did not. Human exposure to microplastics through bottled mineral water was found to be negligible, with daily and annual intake levels well below established safety thresholds.