Microplastic pollution and human risk assessment in Turkish bottled natural and mineral waters

Microplastics (MPs), which arise from the deterioration of larger plastics that are frequently used in daily life and are smaller than 5 mm in size, are found in many environments and can pose a serious threat to human health. Humans ingest these microplastics unintendedly through drinking water. Although plastic pollution has been extensively investigated in a variety of water sources, research on MP contamination in bottled waters is scarce. Hence, in this study, the presence and distribution of MPs were investigated in 150 samples of bottled natural and mineral water brands in Türkiye. Using FTIR stereoscopy and stereomicroscope analysis, MPs were detected in 43 out of the 50 (86%) of these brands. Among the four types of polymers detected, the most abundant type was polyethylene (33%), polypropylene (31%), polyethylene terephthalate (25%), and polyamid (11%). In comparison to natural waters, mineral waters had larger average-sized particles (63.98 ± 4.06 vs. 104.83 ± 14.28 µm) and higher MP concentrations (4.6 ± 0.5 vs. 12.6 ± 1.6 particles/L). Although the most dominant shape was found as fiber in natural waters, fragments were more prevalent in mineral waters. The estimated daily intakes (EDI) for adults and children were expected to be 0.019 and 0.42 MP/kg/bw/day, respectively, in natural waters while EDI were 0.009 and 0.04 MP/kg/bw/day, respectively, in mineral waters. The results of the study suggest that the EDI and annual intake (EAI) are negligible when compared to other studies. The baseline data on MP contamination of bottled water provided in the present study may be significant and useful for researchers to have a better understanding of microplastic contamination exposure.