Microplastics (MPs) are widely detected in urban drinking water systems. However, the presence and characteristics of MPs in mountainous drinking water systems with independent and simple filtration facilities have been overlooked. In this study, we revealed the ubiquity of MPs and demonstrated that their concentrations increased along with the pipeline length in Bainitan Village, Tiantai County, China. The simple filtration facility in this village did not effectively remove most MPs. Polyethylene, polyurethane, and polyethylene terephthalate were the dominant polymers in water samples (72.32% in total), while polyvinylchloride, polyurethane, and polyethylene were the most prevalent in the sediment (74.00% in total) of the reservoir. Long fragments were the predominant shape of MPs in all samples, with the majority being smaller than 100 μm. The estimated daily intake of MPs through drinking water ingestion was highest in infants (2.14-31.26 MPs/kg bw/day), compared to children (1.41-20.67 MPs/kg bw/day) and adults (1.05-15.35 MPs/kg bw/day), highlighting their increased vulnerability. This emphasizes the need for advanced water treatment systems in mountainous regions. It also underscores the necessity for government attention to improve water safety in remote areas. Our research will contribute valuable baseline data for further research on MP exposure, particularly in mountainous communities.
Keywords: daily intake; drinking water; human exposure; microplastic; mountainous area.