The monitoring of water quality, especially of karst springs, requires methods for rapidly estimating and quantifying parameters that indicate contamination. In the last few years, fluorescence‐based measurements of tryptophan and humic acid have become a promising tool to assess water quality in near real‐time. In this study, we conducted comparative tracer tests in a karst experimental site to investigate the transport properties and behavior of tryptophan and humic acid in a natural karst aquifer. These two tracers were compared with the conservative tracer uranine. Fluorescence measurements were conducted with an online field fluorometer and in the laboratory. The obtained breakthrough curves (BTCs) and the modeling results demonstrate that (1) the online field fluorometer is suitable for real‐time fluorescence measurements of all three tracers; (2) the transport parameters obtained for uranine, tryptophan, and humic acid are comparable in the fast flow areas of the karst system; (3) the transport velocities of humic acid are slower and the resulting residence times are accordingly higher, compared to uranine and tryptophan, in the slower and longer flow paths; (4) the obtained BTCs reveal additional information about the investigated karst system. As a conclusion, the experiments show that the transport properties of tryptophan are similar to those of uranine while humic acid is partly transported slower and with retardation. These findings allow a better and quantitative interpretation of the results when these substances are used as natural fecal and contamination indicators.

中文翻译：

---

现场示踪剂测试可评估色氨酸和腐殖酸在岩溶中的传输特性。

监测水质，特别是岩溶泉水的水质，需要用于快速估计和量化指示污染的参数的方法。在过去的几年中，基于荧光的色氨酸和腐殖酸的测量已成为近乎实时评估水质的有前途的工具。在这项研究中，我们在岩溶实验点进行了对比示踪剂测试，以研究天然岩溶含水层中色氨酸和腐殖酸的传输特性和行为。将这两个示踪剂与保守示踪剂尿素进行了比较。使用在线现场荧光计在实验室中进行荧光测量。所获得的穿透曲线和建模结果表明：（1）在线场荧光计适用于所有三个示踪剂的实时荧光测量；（2）在岩溶系统的快速流动地区，获得的尿素，色氨酸和腐殖酸的转运参数相当；（3）与尿酸和色氨酸相比，在较慢和更长的流动路径中，腐殖酸的运输速度较慢，因此停留时间也更长。（4）获得的BTC揭示了有关所研究的岩溶系统的其他信息。结论是，实验表明色氨酸的转运特性与尿酸类似，而腐殖酸的转运速度较慢且具有延迟。