Opening the black box of spring water microbiology from alpine karst aquifers to support proactive drinking water resource management.

Domenico Savio,Georg H Reischer,Robert L Mach,Andreas H Farnleitner,Alexander K.T Kirschner,Hermann Stadler,Rita Linke,Alfred P Blaschke,Katalin Demeter,Ulrich Szewzyk,Inés C Wilhartitz,Philipp Stadler,Regina Sommer

doi:10.1002/wat2.1282

Abstract

Over the past 15 years, pioneering interdisciplinary research has been performed on the microbiology of hydrogeologically well‐defined alpine karst springs located in the Northern Calcareous Alps (NCA) of Austria. This article gives an overview on these activities and links them to other relevant research. Results from the NCA springs and comparable sites revealed that spring water harbors abundant natural microbial communities even in aquifers with high water residence times and the absence of immediate surface influence. Apparently, hydrogeology has a strong impact on the concentration and size of the observed microbes, and total cell counts (TCC) were suggested as a useful means for spring type classification. Measurement of microbial activities at the NCA springs revealed extremely low microbial growth rates in the base flow component of the studied spring waters and indicated the importance of biofilm‐associated microbial activities in sediments and on rock surfaces. Based on genetic analysis, the autochthonous microbial endokarst community (AMEC) versus transient microbial endokarst community (TMEC) concept was proposed for the NCA springs, and further details within this overview article are given to prompt its future evaluation. In this regard, it is well known that during high‐discharge situations, surface‐associated microbes and nutrients such as from soil habitats or human settlements—potentially containing fecal‐associated pathogens as the most critical water‐quality hazard—may be rapidly flushed into vulnerable karst aquifers. In this context, a framework for the comprehensive analysis of microbial pollution has been proposed for the NCA springs to support the sustainable management of drinking water safety in accordance with recent World Health Organization guidelines. Near‐real‐time online water quality monitoring, microbial source tracking (MST) and MST‐guided quantitative microbial‐risk assessment (QMRA) are examples of the proposed analytical tools. In this context, this overview article also provides a short introduction to recently emerging methodologies in microbiological diagnostics to support reading for the practitioner. Finally, the article highlights future research and development needs.This article is categorized under: 1Engineering Water > Water, Health, and Sanitation2Science of Water > Water Extremes3Water and Life > Nature of Freshwater Ecosystems

Highlights

Alpine karst aquifers play a vital role in the drinking water supply in many regions throughout the world (Ford & Williams, 2007a)
The presented studies from the Northern Calcareous Alps (NCA) area and from studies performed by other groups abroad Austria shed considerable light on the microbiology in the spring water from alpine karst aquifers
It could be demonstrated that the hydrogeology and catchment situation of a given system has a strong impact on the microbiological characteristics of the spring

Summary

Introduction

Alpine karst aquifers play a vital role in the drinking water supply in many regions throughout the world (Ford & Williams, 2007a). Maintaining the highest quality standards requires coordinated and information-driven efforts, including the sustainable protection of the catchments, optimized spring-abstraction management, and sufficient final treatment. In particular the information on the microbiological water quality of alpine karst springs has mainly been sourced from a fragmentary puzzle of routinely performed surveillance activities. In-depth knowledge on the different aspects of microbiological water quality was largely missing for alpine karst springs. Intensive research activities on the microbiology of alpine karst springs were prompted at the Northern Calcareous Alps (NCA) of Austria at the start of the new millennium. Thereby, a detailed knowledge on the hydrogeological background of the studied alpine karst model systems was regarded as a basic and essential requirement for the interdisciplinary research efforts

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Conclusion