TRANSPORT AND FATE OF PARTICLES AND MICROBIAL CONTAMINANTS IN KARST AQUIFER SYSTEMS

Although karst aquifers are an important source of drinking water on a global scale and are known to be particularly prone to contamination, contaminant behaviour in such systems has received much less attention so far compared to other aquifer types. This has several reasons such as the high temporal variability of processes in karst aquifers, the limited accessibility, the difficulty to adequately equip sites or the difficulty to study relevant processes in laboratory settings. The present ongoing study focusses on the behaviour of microbial contaminants, which are among the most frequent and problematic contaminants in karst aquifers as they generally deteriorate episodically groundwater quality by short-term, high-level contamination events. Sediments and suspended particles/colloids of different types and origin not only play important roles for the formation and dynamics of karst aquifer systems but are also crucial for the transport and attenuation of microbial contaminants. By integrating global observations of high-resolution time series of turbidity, particle-size distribution and microbial parameters at outlets with process-oriented experiments carried out directly within unique experimental research sites, this presentation provides new insights into key processes that control the fate of faecal and pathogenic microorganisms in karst aquifer systems.