Department of Municipal Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China.
Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
J Hazard Mater. 2023 Oct 5;459:132108. doi: 10.1016/j.jhazmat.2023.132108. Epub 2023 Jul 27.
Microplastics (MPs) are ingested by humans through the daily consumption of drinking water. Pipe scales are recognized as important sites of MPs occurrence in the drinking water distribution system (DWDS). Despite extensive research on drinking water, no study has been conducted to investigate the distribution of MPs in pipe scales within an operational DWDS. The underground placement of DWDSs brings challenges for sampling pipe scales. In this study, 5 tap water and 16 pipe scales samples were collected from a typical DWDS. The analysis of MPs abundance in these 21 samples filled the data gap in the distribution of MPs in both pipe scales and tap water along the DWDSs. MPs were detected in all water samples (1.74-20.88 MPs/L) and pipe scales samples (0.03-3.48 MPs/cm). In tap water, MPs abundance increased abruptly in the stagnant-slow flow region and reached the maximum value (20.88 MPs/L), even surpassing the abundance in raw water (6.42 MPs/L). In the pipe scales, MPs abundance decreased from the upstream to downstream of DWDS and was associated with the heavy metal concentration. MPs smaller than 150 µm accounted for 91.6% of the tap water (21-971 µm) and pipe scales (20-2055 µm). The abundance of MPs showed a logarithmic increase as the size decreased. The proportion of MPs fibers in tap water was lower than that in pipe scales. A total of 35 MPs polymers were detected, with 34 polymers in pipe scales and 26 polymers in tap water. In terms of abundance, polyethylene terephthalate (50.0%) was the dominant polymer in pipe scales, while polyamide (70.3%) was the dominant polymer in tap water. Regarding detection rate, polyamide was detected in all 21 samples, followed by polyurethane in 19 samples. The distribution of MPs along the longitudinal direction of the DWDS was correlated with heavy metal. While the distribution of MPs in the vertical direction of large diameter pipe scales was dependent on their sizes, and densities. The greatest abundance, size and density of MPs were detected at the bottom 120-degree.
微塑料（MPs）通过人类日常饮用水摄入。管垢被认为是饮用水分配系统（DWDS）中 MPs 发生的重要场所。尽管对饮用水进行了广泛的研究，但尚未有研究调查 DWDS 中管垢内 MPs 的分布情况。DWDS 的地下放置给管垢取样带来了挑战。在这项研究中，从一个典型的 DWDS 中采集了 5 个自来水和 16 个管垢样本。对这 21 个样本中 MPs 丰度的分析填补了 DWDS 沿线管垢和自来水中 MPs 分布的空白。所有水样（1.74-20.88 MPs/L）和管垢样本中都检测到 MPs（0.03-3.48 MPs/cm）。在自来水中，MPs 丰度在停滞-缓流区急剧增加，达到最大值（20.88 MPs/L），甚至超过了原水（6.42 MPs/L）的丰度。在管垢中，MPs 丰度从 DWDS 的上游到下游逐渐减少，与重金属浓度有关。小于 150 µm 的 MPs 占自来水（21-971 µm）和管垢（20-2055 µm）的 91.6%。MPs 的丰度随着尺寸的减小呈对数增加。自来水中 MPs 纤维的比例低于管垢中的比例。共检测到 35 种 MPs 聚合物，其中管垢中有 34 种，自来水中有 26 种。就丰度而言，聚对苯二甲酸乙二醇酯（50.0%）是管垢中的主要聚合物，而聚酰胺（70.3%）是自来水中的主要聚合物。就检出率而言，所有 21 个样本中均检出聚酰胺，其次是 19 个样本中的聚氨酯。DWDS 纵向方向上 MPs 的分布与重金属有关。而大直径管垢垂直方向上 MPs 的分布取决于其大小和密度。在底部 120 度处检测到 MPs 的最大丰度、尺寸和密度。
