New insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution

<span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT...

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Main Authors: Nico Goldscheider, Michiel Pronk, Jakob Zopfi
Format: Article
Language:English
Published: Croatian Geological Survey 2010-06-01
Series:Geologia Croatica
Subjects:
Online Access:http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/105
id doaj-7ff36be3c33647d7926ae5148a3b6447
record_format Article
collection DOAJ
language English
format Article
sources DOAJ
author Nico Goldscheider
Michiel Pronk
Jakob Zopfi
spellingShingle Nico Goldscheider
Michiel Pronk
Jakob Zopfi
New insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution
Geologia Croatica
Particle-size distribution, turbidity, fecal bacteria contamination, karst groundwater monitoring, total organic carbon
author_facet Nico Goldscheider
Michiel Pronk
Jakob Zopfi
author_sort Nico Goldscheider
title New insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution
title_short New insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution
title_full New insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution
title_fullStr New insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution
title_full_unstemmed New insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution
title_sort new insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distribution
publisher Croatian Geological Survey
series Geologia Croatica
issn 1330-030X
1333-4875
publishDate 2010-06-01
description <span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><p align="left">Mobile particles play crucial roles for contaminant transport in karst aquifers, but few studies have investigated the relationships between sediment dynamics and contaminants. This is partly due to the difficulty in monitoring suspended particles: Turbidity is easy to measure but does not deliver detailed information on the size and type of particles; mineralogical laboratory analyses are laborious and not suitable for continuous monitoring. A portable particle counter was used for the study presented here. The instrument delivers time-series of particle-size distribution (PSD), i.e. the number and diameter of suspended particles, grouped into different size-classes ranging from 0.9 to 139 μm. The test site is a karst system near the city of Yverdon-les-Bains, Switzerland. A swallow hole draining agricultural land is connected to two karst springs, 4.8 and 6.3 km away, which are occasionally contaminated by faecal bacteria at highly variable levels. Turbidity alone turned out not to be a reliable indicator for microbial contamination. To obtain more insight into bacteria and particle transport towards the springs, a comprehensive research program was carried out, including tracer tests and monitoring of PSD, turbidity, total organic carbon (TOC), faecal bacteria(</p></span></span></span></span><em><span style="font-family: TimesNewRomanPS-ItalicMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPS-ItalicMT; font-size: xx-small;">E.coli</span></span></em><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">) and various hydrologic and physicochemical parameters. Results show that there are two types of turbidity: A primary turbidity signal occurs shortly after rainfall during the rising limb of the hydrograph; a secondary signal typically occurs during spring flow recession. The first signal is explained by remobilization of conduit sediments due to a hydraulic pressure pulse (autochthonous or pulse-through turbidity). The second peak indicates the arrival of water from the swallow hole, often together with TOC and faecal bacteria (allochthonous or flow-through turbidity). PSD analyses revealed that autochthonous turbidity is composed of a broad mixture of fine and large particles, while allochthonous turbidity predominantly consists of very fine particles. This is explained by sedimentation of larger particles between the swallow hole and the springs. During allochthonous turbidity periods, very good correlation between the finest particles (0.9–1.5 μm) and </span></span><em><span style="font-family: TimesNewRomanPS-ItalicMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPS-ItalicMT; font-size: xx-small;">E. coli </span></span></em><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">was found (R</span></span><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">2 </span></span><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">= 0.93). The relative increase of fine particles can consequently be used as an “early-warning parameter” for microbial contamination of karst spring water. Further applicability and limitations of this approach are also discussed. </span></span>
topic Particle-size distribution, turbidity, fecal bacteria contamination, karst groundwater monitoring, total organic carbon
url http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/105
work_keys_str_mv AT nicogoldscheider newinsightsintothetransportofsedimentsandmicroorganismsinkarstgroundwaterbycontinuousmonitoringofparticlesizedistribution
AT michielpronk newinsightsintothetransportofsedimentsandmicroorganismsinkarstgroundwaterbycontinuousmonitoringofparticlesizedistribution
AT jakobzopfi newinsightsintothetransportofsedimentsandmicroorganismsinkarstgroundwaterbycontinuousmonitoringofparticlesizedistribution
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spelling doaj-7ff36be3c33647d7926ae5148a3b64472020-11-25T01:20:03ZengCroatian Geological SurveyGeologia Croatica1330-030X1333-48752010-06-0163213714210.4154/gc.2010.1070New insights into the transport of sediments and microorganisms in karst groundwater by continuous monitoring of particle-size distributionNico Goldscheider0Michiel Pronk1Jakob Zopfi2Centre of Hydrogeology, University of NeuchâtelCentre of Hydrogeology, University of NeuchâtelInstitute of Geology and Paleontology, University of Lausanne<span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><p align="left">Mobile particles play crucial roles for contaminant transport in karst aquifers, but few studies have investigated the relationships between sediment dynamics and contaminants. This is partly due to the difficulty in monitoring suspended particles: Turbidity is easy to measure but does not deliver detailed information on the size and type of particles; mineralogical laboratory analyses are laborious and not suitable for continuous monitoring. A portable particle counter was used for the study presented here. The instrument delivers time-series of particle-size distribution (PSD), i.e. the number and diameter of suspended particles, grouped into different size-classes ranging from 0.9 to 139 μm. The test site is a karst system near the city of Yverdon-les-Bains, Switzerland. A swallow hole draining agricultural land is connected to two karst springs, 4.8 and 6.3 km away, which are occasionally contaminated by faecal bacteria at highly variable levels. Turbidity alone turned out not to be a reliable indicator for microbial contamination. To obtain more insight into bacteria and particle transport towards the springs, a comprehensive research program was carried out, including tracer tests and monitoring of PSD, turbidity, total organic carbon (TOC), faecal bacteria(</p></span></span></span></span><em><span style="font-family: TimesNewRomanPS-ItalicMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPS-ItalicMT; font-size: xx-small;">E.coli</span></span></em><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">) and various hydrologic and physicochemical parameters. Results show that there are two types of turbidity: A primary turbidity signal occurs shortly after rainfall during the rising limb of the hydrograph; a secondary signal typically occurs during spring flow recession. The first signal is explained by remobilization of conduit sediments due to a hydraulic pressure pulse (autochthonous or pulse-through turbidity). The second peak indicates the arrival of water from the swallow hole, often together with TOC and faecal bacteria (allochthonous or flow-through turbidity). PSD analyses revealed that autochthonous turbidity is composed of a broad mixture of fine and large particles, while allochthonous turbidity predominantly consists of very fine particles. This is explained by sedimentation of larger particles between the swallow hole and the springs. During allochthonous turbidity periods, very good correlation between the finest particles (0.9–1.5 μm) and </span></span><em><span style="font-family: TimesNewRomanPS-ItalicMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPS-ItalicMT; font-size: xx-small;">E. coli </span></span></em><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">was found (R</span></span><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">2 </span></span><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;"><span style="font-family: TimesNewRomanPSMT; font-size: xx-small;">= 0.93). The relative increase of fine particles can consequently be used as an “early-warning parameter” for microbial contamination of karst spring water. Further applicability and limitations of this approach are also discussed. </span></span>http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/105Particle-size distribution, turbidity, fecal bacteria contamination, karst groundwater monitoring, total organic carbon