Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
J Environ Sci (China). 2022 Jul;117:37-45. doi: 10.1016/j.jes.2021.12.032. Epub 2022 Jan 4.
Water quality deterioration often occurs in secondary water supply systems (SWSSs), and increased heavy metal concentrations can be a serious problem. In this survey, twelve residential neighborhoods were selected to investigate the influence of SWSSs on the seasonal changes in heavy metal concentrations from input water to tank and tap water. The concentrations of nine evaluated heavy metals in all groups of water samples were found to be far below the specified standard levels in China. The concentrations of Fe, Mn, and Zn increased significantly from the input water samples to the tank and tap water samples in spring and summer (p < 0.05), especially for the water samples that had been stagnant for a long time. Negative correlations were found between most of the heavy metals and residual chlorine (Fe, Cu, Zn, and As, r = -0.186 to -0.519, p < 0.05). In particular, a high negative correlation was observed between Fe and residual chlorine (r = -0.489 to -0.519, p < 0.01) in spring and summer. Fe and Mn displayed positive correlations with turbidity (r = 0.672 and 0.328, respectively; p < 0.05). In addition, Cr and As were found to be positively associated with some nutrients (NO, TN, and SO; r = 0.420-0.786, p < 0.01). The material of the storage tanks had little influence on the difference in heavy metal concentrations. Overall, this survey illustrated that SWSSs may pose a chronic threat to water quality and could provide useful information for practitioners.
水质恶化经常发生在二次供水系统 (SWSSs) 中，重金属浓度的增加可能是一个严重的问题。在这项调查中，选择了十二个住宅区，以研究 SWSSs 对输入水到水箱和自来水的重金属浓度季节性变化的影响。所有水样中 9 种评价重金属的浓度均远低于中国规定的标准水平。在春夏季，输入水样到水箱和自来水水样中 Fe、Mn 和 Zn 的浓度明显增加（p<0.05），特别是长时间停滞的水样。大多数重金属与余氯之间存在负相关关系（Fe、Cu、Zn 和 As，r=-0.186 至-0.519，p<0.05）。特别是在春夏季，Fe 和余氯之间存在很强的负相关关系（r=-0.489 至-0.519，p<0.01）。Fe 和 Mn 与浊度呈正相关（r=0.672 和 0.328，分别为 p<0.05）。此外，Cr 和 As 与一些营养物质（NO、TN 和 SO）呈正相关（r=0.420-0.786，p<0.01）。储水箱的材料对重金属浓度的差异影响不大。总体而言，本调查表明 SWSSs 可能对水质构成慢性威胁，并可为从业者提供有用信息。
