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). 2023 Mar;125:148-159. doi: 10.1016/j.jes.2022.01.036. Epub 2022 Feb 1.
Urban villages are unique residential neighborhoods in urban areas in China. Roof tanks are their main form of water supply, and water quality deterioration might occur in this system because of poor hygienic conditions and maintenance. In this study, water samples were seasonally collected from an urban village to investigate the influence of roof tanks as an additional water storage device on the variation in the microbial community structure and pathogenic gene markers. Water stagnation in the roof tank induced significant decreases in chlorine (p < 0.05), residual chlorine was as low as 0.02 mg/L in spring. Propidium monoazide (PMA)-qPCR revealed a one-magnitude higher level of total viable bacterial concentration in roof tank water samples (2.14 ± 1.81 × 10 gene copies/mL) than that in input water samples (3.57 ± 2.90 × 10 gene copies/mL, p < 0.05), especially in spring and summer. In addition, pathogenic fungi, Mycobacterium spp., and Legionella spp. were frequently detected in the roof tanks. Terminal users might be exposed to higher microbial risk induced by high abundance of Legionella gene marker. Spearman's rank correlation and redundancy analysis showed that residual chlorine was the driving force that promoted bacterial colonization and shaped the microbial community. It is worth noted that the sediment in the pipe will be agitated when the water supply is restored after the water outages, which can trigger an increase in turbidity and bacterial biomass. Overall, the findings provide practical suggestions for controlling microbiological health risks in roof tanks in urban villages.
城市村庄是中国城市地区独特的住宅区。屋顶水箱是其主要的供水形式，由于卫生条件和维护不善，该系统的水质可能会恶化。本研究季节性地从一个城市村庄采集水样，以调查屋顶水箱作为额外的储水装置对微生物群落结构和病原基因标志物变化的影响。水箱中的水停滞导致氯含量显著下降（p < 0.05），春夏季残留氯低至 0.02 毫克/升。吖啶橙单染（PMA）-qPCR 显示，屋顶水箱水样中的总活菌浓度比进水样高一个数量级（2.14 ± 1.81×10 基因拷贝/mL）（p < 0.05），尤其是在春夏季。此外，真菌、分枝杆菌和军团菌经常在屋顶水箱中被检测到。终端用户可能会因军团菌基因标志物的高丰度而面临更高的微生物风险。Spearman 秩相关和冗余分析表明，残留氯是促进细菌定殖和塑造微生物群落的驱动力。值得注意的是，停水后恢复供水时，管道中的沉积物会被搅动，这会导致浊度和细菌生物量增加。总的来说，这些发现为控制城市村庄屋顶水箱中的微生物健康风险提供了实用建议。
