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Occurrence and Removal Efficiency of Microplastics in Four Drinking Water Treatment Plants in Zhengzhou, China

Water 2023 11 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Yang Li, Yinghui Meng, Liwen Qin, Minghui Shen, Tongtong Qin, Xudong Chen, Beibei Chai, Yue Liu, Yanyan Dou, Yanyan Dou, Xuejun Duan

Summary

Researchers sampled four drinking water treatment plants in Zhengzhou, China, and found microplastics in raw water (13–25 particles per litre) with only partial removal — fibers and fragments dominated, and the treatment process actually shifted polymer composition, with PET becoming the most prevalent type in finished drinking water. The study is significant because it demonstrates that standard treatment cannot fully eliminate microplastics from tap water, meaning that people are regularly consuming microplastics from treated municipal supplies.

Study Type Environmental

As an emerging contaminant, the presence of microplastics is widespread in the environment. However, current research regarding the removal of microplastics by drinking water treatment plants (DWTPs) remains insufficient. This study aims to investigate microplastics in water and sludge in four DWTPs in Zhengzhou; these DWTPs have different water sources. The results revealed that the abundance of microplastics in raw water ranged from 12.80 ± 0.80 to 25.07 ± 1.67 n/L. Overall, fibers and fragments ranging from 10 to 100 μm constituted the primary components. The proportion of white and transparent microplastics was the highest. Among the ten polymer types detected, polyvinyl chloride, polyphenylene oxide, and polyethylene terephthalate were the predominant ones in raw water; polyethylene terephthalate emerged as the prevalent polymer type in treated drinking water, with both polyethylene terephthalate and polyvinyl chloride being primarily present in sludge. The removal rate of microplastics ranged from 45.8% to 74.5%. Furthermore, the removal rates at the sedimentation tank outlet accounted for more than 50.0% of the total removal rate. The abundance of microplastics in sludge was significantly higher than that in water, indicating a concentrated environment for the persistence of microplastics. The proper disposal of sludge has emerged as one of the challenges requiring our attention.

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