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Faecal Indicator Bacteria: Groundwater Dynamics and Transport Following Precipitation and River Water Infiltration

Page, Rebecca ; Scheidler, Stefan ; Polat, Elif ; Svoboda, Paul ; Huggenberger, Peter

In: Water, Air, & Soil Pollution, 2012, vol. 223, no. 5, p. 2771-2782

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    Titre
    • Faecal Indicator Bacteria: Groundwater Dynamics and Transport Following Precipitation and River Water Infiltration
    Auteur
    • Page, Rebecca. Department of Environmental Sciences, Applied and Environmental Geology, Institute of Geology and Paleontology, University of Basel, Bernoullistrasse 32, 4056, Basel, Switzerland
    • Scheidler, Stefan. Department of Environmental Sciences, Applied and Environmental Geology, Institute of Geology and Paleontology, University of Basel, Bernoullistrasse 32, 4056, Basel, Switzerland
    • Polat, Elif. Swiss Tropical and Public Health Institute, University of Basel, Socinstrasse 57, 4051, Basel, Switzerland
    • Svoboda, Paul. Cantonal Laboratory Basel-Landschaft, Gräubernstrasse 12, 4110, Liestal, Switzerland
    • Huggenberger, Peter. Department of Environmental Sciences, Applied and Environmental Geology, Institute of Geology and Paleontology, University of Basel, Bernoullistrasse 32, 4056, Basel, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Water, Air, & Soil Pollution, 2012, vol. 223, no. 5, p. 2771-2782. Springer Netherlands
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:316113
    Summary
    Faecal contamination of drinking water extracted from alluvial aquifers can lead to severe problems. River water infiltration can be a hazard for extraction wells located nearby, especially during high discharge events. The high dimensionality of river-groundwater interaction and the many factors affecting bacterial survival and transport in groundwater make a simple assessment of actual water quality difficult. The identification of proxy indicators for river water infiltration and bacterial contamination is an important step in managing groundwater resources and hazard assessment. The time resolution of microbial monitoring studies is often too low to establish this relationship. A proxy-based approach in such highly dynamic systems requires in-depth knowledge of the relationship between the variable of interest, e.g. river water infiltration, and its proxy indicator. In this study, continuously recorded physico-chemical parameters (temperature, electrical conductivity, turbidity, spectral absorption coefficient, particle density) were compared to the counts for faecal indicator bacteria, Escherichia coli and Enterococcus sp. obtained from intermittent sampling. Sampling for faecal indicator bacteria was conducted on two temporal scales: (a) routine bi-weekly monitoring over a month and (b) intense (bi-hourly) event-based sampling over 3 days triggered by a high discharge event. Both sampling set-ups showed that the highest bacterial concentrations occurred in the river. E. coli and Enterococcus sp. concentrations decreased with time and length of flow path in the aquifer. The event-based sampling was able to demonstrate differences in bacterial removal between clusters of observation wells linked to aquifer composition. Although no individual proxy indicator for bacterial contamination could be established, it was shown that a combined approach based on time-series of physico-chemical parameters could be used to assess river water infiltration as a hazard for drinking water quality management