Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
Chemosphere. 2021 Mar;267:129270. doi: 10.1016/j.chemosphere.2020.129270. Epub 2020 Dec 10.
The re-release of heavy metals accumulated in the drinking water distribution systems (DWDSs) may pose a significant threat to water quality and human health. In this work, the pipe scales in the actual DWDS were collected, and their physicochemical characteristics were investigated by SEM, XRF, XRD, XPS, and sequential extraction procedure. The co-release potential of heavy metals under different scale dosages, temperatures, and stagnation times was explored by stagnation release tests. Pearson correlation analysis on metal release and human health risk assessment was used to reveal the inter-metal correlation and potential risk of metal release. The results showed that the metal release potential under stagnation water conditions arose primarily from the acid-soluble fraction. The chronic non-carcinogenic risk of soluble metals followed the order: Mn > Fe > Zn > Pb. The risk caused by the soluble metal release could be ignored (HI < 1, HI: hazard index) under normal stagnation times (within 8 h). The major finding of this work was that Ca and Mn were more labile to release and had a significant linear co-release correlation (scale powder: R = 0.906, p < 0.01; pipe section: R = 0.982, p < 0.01), which indicated their co-existence and linear co-release. Ca was recognized as the "major metal" that affected the release of trace metals. The health risk probably increased with the release of Ca, which could also be used as an "indicator" of Mn release.
饮用水分配系统（DWDS）中重金属的再释放可能对水质和人体健康构成重大威胁。在这项工作中，采集了实际 DWDS 中的管道水垢，并通过 SEM、XRF、XRD、XPS 和顺序提取程序研究了其理化特性。通过停滞释放试验探讨了不同水垢剂量、温度和停滞时间下重金属的共释放潜力。通过金属释放的皮尔逊相关性分析和人体健康风险评估，揭示了金属释放的相互关系和潜在风险。结果表明，停滞水条件下的金属释放潜力主要来自于酸可溶部分。可溶性金属的慢性非致癌风险顺序为：Mn > Fe > Zn > Pb。在正常停滞时间（8 小时内）下，可溶性金属释放引起的风险可以忽略不计（HI < 1，HI：危害指数）。这项工作的主要发现是 Ca 和 Mn 更容易释放，并且具有显著的线性共释放相关性（水垢粉末：R = 0.906，p < 0.01；管道部分：R = 0.982，p < 0.01），表明它们的共存和线性共释放。Ca 被认为是影响痕量金属释放的“主要金属”。健康风险可能随着 Ca 的释放而增加，也可以作为 Mn 释放的“指示剂”。
