Microplastic Transportation in a Typical Drinking Water Supply: From Raw Water to Household Water

Microplastics in drinking water have attracted increasing global concerns due to their potential adverse impacts on human health. However, there needs to be more knowledge of the occurrence and distribution of microplastics in drinking water systems from water sources to household tap water. Herein, laser direct infrared spectroscopy is used to investigate the occurrence of microplastics in a typical drinking water plant with different water sources. Microplastic information is further used to understand microplastic fates during drinking water supply, including microplastic abundance, size, shape, and polymer type. Overall, the microplastic abundance in treated water ranges from 12.00 to 25.33 particles/L, higher than those in raw water (RW; 2.33–17.33 particles/L) and household water (HW; 8.00–19.67 particles/L), which shows that microplastics are not removed from RW. The main polymers in these microplastics are polyethylene terephthalate, polyvinyl chloride, polyethylene, and polypropylene. At the same time, the main microplastic shapes are fragments and fibers. Small-sized microplastics of 20–100 μm account for up to 76.74% and 79.30% of microplastics during the dry and wet seasons, respectively. Additionally, more microplastics are detected in RW from rivers than those from reservoirs and lakes, and the microplastic abundance in the wet season is higher than that in the dry season. As expected, the potential ecological risk of microplastics in all waters is the I level, which is the lowest level. Most importantly, the annual microplastic intake of an adult via drinking water is 5063–18,301 microplastics, less than that reported in previous studies. These results provide valuable data on the fates of microplastics in drinking water supply systems from water sources to HW and promote authorities to update the treatment technologies for drinking water in the future to remove microplastics efficiently.