Department of Civil, Structural and Environmental Engineering, University of Dublin, Trinity College, Dublin, Ireland.
Department of Civil, Structural and Environmental Engineering, University of Dublin, Trinity College, Dublin, Ireland.
J Contam Hydrol. 2023 Mar;254:104129. doi: 10.1016/j.jconhyd.2022.104129. Epub 2023 Jan 3.
Karst springs are globally important for drinking water supply but are often also exceptionally vulnerable to contamination. Such springs usually exhibit strong variation in microbial water quality in sharp response to rainfall events, thus, posing a health hazard to consumers of water supplied from these sources. The rapid detection of such changes is extremely important as well as being able to establish a link to the sources of such pollution, so that appropriate measures can be taken both in terms of immediate protection of human health and the management of karst aquifers. In this study, a fluorescence-based multi-parameter approach was trialed in order to evaluate which methods can be used to monitor rainfall-induced rapid changes in microbial water quality at karst springs, as well as determine whether such changes can be linked to sources of human effluent contamination. The results from three monitoring periods at two karst springs revealed marked responses to rainfall events for all of the microbial parameters measured. Total cell count (TCC) measurements using flow cytometry (FCM) showed very strong positive correlations with the more conventionally monitored faecal indicator bacteria (FIB) and total coliforms (TC), indicating that such a fluorescence-based and cultivation-independent technique can be very useful to indicate rapid changes in microbial water quality at karst springs. Furthermore, very strong positive correlations were also found between tryptophan-like fluorescence (TLF) measurements and concentrations of all monitored microbial parameters, again demonstrating that such a fluorescence-based approach can also be useful for detecting rapid changes in concentrations of traditional faecal indicators. Interestingly, it was found that fluorescent whitening compounds (FWCs) signals do not necessarily follow temporal variations of microbial indicators. However, the frequency of detection of positive FWCs signals may still reveal useful information about the overall magnitude of human wastewater effluent impacts on karst aquifer systems.
喀斯特泉对饮用水供应至关重要，但通常也极易受到污染。这些泉水的微生物水质通常会随着降雨事件发生剧烈变化，从而对这些水源的消费者构成健康威胁。因此，快速检测此类变化并建立与污染来源的联系非常重要，以便能够采取措施，立即保护人类健康和管理喀斯特含水层。在这项研究中，尝试了一种基于荧光的多参数方法，以评估哪些方法可用于监测喀斯特泉中微生物水质因降雨而引起的快速变化，并确定此类变化是否可归因于人类污水污染的来源。在两个喀斯特泉的三个监测期内，所有测量的微生物参数都对降雨事件产生了明显的响应。使用流式细胞术 (FCM) 进行的总细胞计数 (TCC) 测量与传统监测的粪便指示菌 (FIB) 和总大肠菌群 (TC) 呈非常强的正相关，表明这种基于荧光和非培养的技术对于指示喀斯特泉微生物水质的快速变化非常有用。此外，色氨酸样荧光 (TLF) 测量值与所有监测的微生物参数浓度之间也存在很强的正相关，再次表明这种基于荧光的方法也可用于检测传统粪便指示物浓度的快速变化。有趣的是，发现荧光增白剂 (FWCs) 信号不一定随微生物指标的时间变化而变化。但是，阳性 FWCs 信号的检测频率仍可能揭示有关人类废水对喀斯特含水层系统的整体影响的有用信息。
