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GQ10: Groundwater Quality Management in a Rapidly Changing World

Edited by Mario Schirmer, Eduard Hoehn & Tobias Vogt

IAHS Publ. 342 (2011) ISBN 978-1-907161-16-2, 512 + xvi pp. Price £

Groundwater is a vital resource and a conveyor belt for dissolved and particulate matter. It is a crucial component of local, regional and global water cycles, and the quality of groundwater is inextricably linked with global environmental and social viability. The GQ10 conference focused on the need to manage, sustain, repair and protect groundwater quality under rapidly changing climatic and global conditions. The aim was to build a bridge between contaminant hydro(geo)logy to other scientific disciplines and to society.

Abstracts of the papers in this volume

can be seen at:

www.iahs.info

http://www.iahs.info/

Preface

The GQ10 conference theme was Groundwater Quality Management in a Rapidly Changing World, and focused on the need to manage, sustain, repair and protect groundwater quality under rapidly changing climatic and global conditions. We aimed to build a bridge between contaminant hydro(geo)logy to other scientific disciplines and to society. Groundwater is a vital resource and a conveyor belt for dissolved and particulate matter. It is a crucial component of local, regional and global water cycles, and the quality of groundwater is inextricably linked with global environmental and social viability.

The conference brought together researchers, regulators, contractors, consultants, planners and water supply agencies to address the important issues related to groundwater quality. We addressed a wide range of groundwater issues including:

Groundwater quality under conditions of global / climate change Processes at groundwater–surface water interfaces Biogeochemical interactions Groundwater ecosystems Urban hydrogeology Emerging chemicals of concern Geogenic contaminants including radio isotopes Non-aqueous phase liquids (LNAPLs and DNAPLs) Groundwater at complex contaminated mega-sites Contaminant dynamics in karst systems Natural attenuation Innovative clean-up technologies Protecting and managing groundwater quality Policy and controls on groundwater quality Vadose zone processes Salinization of groundwater resources Groundwater scarcity Groundwater quality issues in aquifer storage and water re-useWe experienced socially and technically stimulating discussions. With the GQ10

conference, we truly hope that we were able to move groundwater science forward and could further combine our continuing efforts for the benefit of human kind.

GQ10 was the seventh in an international series of conferences, held under the aegis of the International Association of Hydrological Sciences (IAHS), which is organized every three years. The last two conferences took place in Waterloo (Canada) in 2004 and Fremantle (Australia) in 2007. With GQ10, hosted by Eawag in Zurich, Switzerland, 13–18 June 2010, the series returned to Europe.

The research papers presented at GQ10 by leading scientists and water professionals from around the world formed a valuable summary of the state of knowledge in these areas. The present publication consists of 115 selected and peer-reviewed papers from GQ10. They include both oral and poster papers presented at GQ10. They were selected for publication by the GQ10 Editorial Board and Scientific Committee from over 270 abstracts submitted from 37 countries.

Mario Schirmer, Eduard Hoehn & Tobias VogtEawag–Swiss Federal Institute of Aquatic Science and Technology,

Überlandstrasse 133, 8600 Dübendorf, Switzerland

The editors wish to thank all conference authors and reviewers for their cooperation during the compilation of this book. We especially thank Samuel Diem, Sabrina Bahnmueller and Matthias Rudolf von Rohr (all Eawag) for putting together all conference papers before GQ10 started. We very much appreciate their enthusiasm and support.

The conference was organised by the Conference Committee: Mario Schirmer, Eawag, University of Neuchâtel (Chairman) Eduard Hoehn, Eawag (Co-Chairman) Tobias Vogt, Eawag Peter Huggenberger, University of Basel Daniel Hunkeler, University of Neuchâtel Wolfgang Kinzelbach, ETH Zurich Ronald Kozel, Swiss Federal Office for the Environment Fritz Stauffer, ETH Zurich

The conference organisers gratefully acknowledge the support of the following sponsors: Eawag, Swiss Federal Institute of Aquatic Science and Technology Swiss National Science Foundation Swiss Federal Office for the Environment (BAFU) STS Sensors Ltd. ÅF-Colenco Ltd. Swiss Cooperative for the Disposal of Radioactive Waste, NAGRA Intera Inc. Swiss Association of Geologists, CHGeol Simultec AG Roche Innovative Messtechnik Weiss Bachema AG Swiss Association for the Gas and Water Industry, SVGW Solexperts Ltd. Stump Foratec Ltd. Malcolm Pirnie

They also thank the members of the International Scientific Committee: Mike Annable , University of Florida (USA) Jim Barker, University of Waterloo (Canada) Barbara Bekins, United States Geological Survey (USA) Poul Bjerg, Technical University of Denmark (Denmark) Greg Davis, CSIRO Land and Water (Australia) Georgia Destouni, University of Stockholm (Sweden) Peter Grathwohl, University of Tübingen (Germany) Mary Hill, United States Geological Survey (USA) Colin Johnston, CSIRO Land and Water (Australia) David Lerner, University of Sheffield (UK) Sascha Oswald, University of Potsdam (Germany) Henning Prommer, CSIRO Land and Water (Australia) Suresh Rao, Purdue University (USA) Mike Rivett, University of Birmingham (UK) Ed Sudicky, University of Waterloo (Canada) Mike Trefry, CSIRO Land and Water (Australia) Yanxin Wang, China University of Geosciences (China)

Chunmiao Zheng, University of Alabama (USA)

Contents

Preface by Mario Schirmer, Eduard Hoehn & Tobias Vogt v

1 Groundwater quality under conditions of global climate changes

Groundwater quality, climate and irrigation: large-scale, long-term trends in the Aral Sea Drainage Basin Jerker Jarsjö & Rebecka Törnqvist

3

Climate change impact on the leaching of a heavy metal contamination in a small lowland catchment Ate Visser, Joop Kroes, Michelle van Vliet, Stephen Blenkinsop & Hans Peter Broers

7

Groundwater characteristic of the Najd aquifers, Oman, derived from isotope and hydrochemical signatures K. Al-Mushaikhi, G. Strauch, K. Osenbrück, T. Müller, K. Knöller & S. Oswald

11

2 Policy and Controls on Groundwater Quality

Incorporating groundwater quality in the water-supply and sanitation sector development program for Bangladesh Kazi Matin Ahmed & Peter Ravenscroft

17

Optimal fertilizer control for meeting EU groundwater nitrate concentration standards: El Salobral-Los Llanos case study S. Peña-Haro, M. Pulido-Velazquez & C. Llopis-Qlbert

21

3 Groundwater Scarcity

Large-scale modelling of groundwater resources in an arid region Edda Kalbus, Sascha Oswald, Wenqing Wang, Olaf Kolditz, Irina Engelhardt, Mohammed I. Al-Saud & Randolf Rausch

27

Eighty-year variability in rainfall in northern Nigeria and its effect on aquifer recharge S. A. Ayanlaja

31

1

4 Urban Hydrogeology

Methodologies and tools for the estimation of mass fluxes of xenobiotics at different scales in urban areas Frido Reinstorf, Sebastian Leschik, Andreas Musolff, Hans-Reinhard Gläser, Karsten Osenbrück, Monika Möder, Gerhard Strauch & Mario Schirmer

37

Investigation and modelling of the degradation during rapid sand filtration and redox sensitivity of the industrial contaminant p-TSA R. Meffe, G. Massmann, C. Kohfahl, T. Taute, E. Holzbecher, D. Richter & U. Dünnbier

42

Optimal sampling schedules of integral pumping tests for the investigation of groundwater contamination from urban line sources Sebastian Leschik, Marti Bayer-Raich, Andreas Musolff & Mario Schirmer

46

Manufactured nanoparticle movement in the groundwaters of a redbed sandstone: laboratory experiments and field observations John Tellam, Richard Greswell, Michael Riley & Syed Rahman

50

Dynamic plant uptake modelling and mass flux estimation A. Rein, P. Bauer-Gottwein & S. Trapp

55

Micropollutant mass flow in urban receiving waters Andreas Musolff, Sebastian Leschik, Gerhard Strauch & Mario Schirmer

59

Multi-chemical and isotope approach for studying shallow and deep groundwater interaction in an urban area: the case of Tivoli Plain (central Italy) V. Carucci, M. Petitta & R. Aravena

63

Thermal groundwater use in urban areas – spatiotemporal scales and concepts Jannis Epting, Peter Huggenberger & Christoph Butscher

67

Groundwater quality of upper and lower Dupi Tila aquifers in the megacity Dhaka, Bangladesh K. M. Ahmed, S. Sultana, M. A. Hasan, P. Bhattacharya, M. K. Hasan, W. G. Burgess & M. A. Hoque

71

Hydrochemical and microbiological assessment of groundwater from the weathered basement aquifer in Ibadan Metropolis, SW-Nigeria Moshood N. Tijani & Seybatou Diop

75

Assessment of groundwater vulnerability and quality under urban-industrial influence in a subtropical town of north India D. C. Singhal, H. Joshi & V. K. Sharma

79

Societal costs for remediation of an MTBE groundwater contamination by air stripping Mario Schirmer & Horst Niemes

84

Simulation of the impact of the South to North Water Transfer Project on groundwater in the Beijing plain Yang Yong, Li Guo-Min, Dong Yan-Hui, Li Ming, Yang Jiang-Qing, Zhou Dong & Yang Zhong-Shan

88

Reasonable exploitation of groundwater based on numerical simulation in Pinggu basin, Beijing, China Hai-Zhen Xu, Guo-Min Li, Shou-Quan Zhang, Yan-Hui Dong & Ming Li

92

5 Emerging Chemicals of Concern

A new approach for calculating the predicted environmental concentration of human pharmaceuticals in groundwater at bank filtration sites Beate Müller, Traugott Scheytt, Matthias Zippel, Stephan Hannappel, Jutta Klein-Goedicke & Klaus Duscher

99

The artificial sweetener acesulfame as marker of domestic wastewater in groundwater Ignaz J. Buerge, Hans-Rudolf Buser, Maren Kahle, Markus D. Müller & Thomas Poiger

103

Laboratory simulated transport of microcystin-LR and cylindrospermopsin in groundwater under the influence of stormwater ponds: implications for harvesting of infiltrated stormwater Andrew M. O’Reilly, Martin P. Wanielista, Keith A. Loftin & Ni-Bin Chang

107

Perfluorinated chemicals in Swiss groundwater – results of the National Groundwater Monitoring NAQUA Miriam Reinhardt, Ronald Kozel, Stephanie Zimmermann, Heinz Rupp, Otmar Zoller & Eduard Hoehn

112

Investigations of industrial waste migration in a heterogeneously layered medium Julia V. Fedorova & Alexey V. Lekhov

116

6 Non-aqueous Phase Liquids (LNAPLS and DNAPLS)

Long-term natural attenuation of crude oil in the subsurface Barbara Bekins, Mary Jo Baedecker, Robert P. Eganhouse & William N. Herkelrath

123

Simulation of DNAPL distribution depending on groundwater flow velocities using TMVOC Katharina Erning, Dirk Schäfer, Andreas Dahmke, Antonella Luciano, Paolo Viotti & Marco Petrangeli Papini

128

Source functions for multi-component DNAPLs based on streamtube analysis Michael C. Brooks, A. Lynn Wood & James W. Jawitz

132

Mass depletion–mass flux reduction relationships during pumping used to determine source zone mass of a reactive brominated-solvent DNAPL C. D. Johnston, G. B. Davis, T. P. BAstow, M. D. Annable, M. G. Trefry, A. Furness, Y. Geste, R. Woodbury & S. Rhodes

136

Evaluation of multi-component NAPL source zone screening models by numerical simulation C. Beyer, D. Schäfer, C. H. Park, O. Kolditz & S. Bauer

140

Three-dimensional modelling and analysis of dense nonaqueous phase liquid source zone architecture in heterogeneous soil Chiu-Shia Fen & Changchieh Tsai

144

The use of dynamic contact angle measurement to assess NAPL wetting hysteresis John Heneghan & Ryan D. Wilson

148

Laboratory testing of temperature increases, surfactants and co-solvents as options to enhance dissolution in a brominated-solvent source zone G. B. Davis, T. P. Bastow, C. D. Johnston, B. M. Patterson, M. D. Annable, P. S. C. Rao, Y. Geste, R. J. Woodbury & S. Rhodes

152

7 Groundwater at Complex Contaminated Mega-Sites

A regional flux-based risk assessment approach for multiple contaminated sites on groundwater bodies S. Brouyère, P. Jamin, F. Dollé, B. Chisala, Ph. Orban, I.-C. Popescu, C. Hérivaux & A. Dassargues

159

Integrated screening level evaluation of megasite redevelopment S. Schädler, M. Morio & M. Finkel

163

Drinking water production close to contaminant sites: a case study from the region of Basel, Switzerland Adrian Auckenthaler, Dominik Baenninger, Annette Affolter, Eric Zechner & Peter Huggenberger

167

Three-dimensional numerical simulation of groundwater contamination by organoarsenic compounds in Kamisu City, Japan S. Watanabe, N. Egusa, T. Hirata, N. Yokoyama, Y. Yamazato & M. Morita

171

From conceptual to numerical modelling of a complex contaminated site in Italy Francesca Bozzano, Nicolò Colombani, Micol Mastrocicco & Marco Petitta

176

Experimental and mathematical methods to quantify the water flux and the transport processes in heterogeneous aquifer model systems Marko Hünniger, Susanne I. Schmidt, Nicolas Peuckmann & Piotr MaŁoszewski

180

Influence of pore water and microbial heterogeneities on the evolution of NAPL contamination at old mega sites D. Puigserver, L. Cónsola, J. M. Carmona, J. M. Nieto, A. Cortés & M. Grifoll

184

A screening level method to derive contaminant distributions in groundwater for early stage assessments of brownfields Maximilian Morio & Michael Finkel

189

Contaminated mega-site management: the complex problem challenge Mario Schirmer, Katharine N. Farrell, Ken Lyon & James Armstrong

194

8 Innovative Clean-up Technologies

Persulfate treatment of gasoline-range organics K. Sra, N. R. Thomson & J. F. Barker

201

Testing an autotrophic sulfate reduction reactor to treat sulfate-rich groundwaters highly contaminated by mining activities Felix Bilek & Stephan Wagner

205

Evaluation in a continuous-flow column of different fermenting substrates for the reductive dehalogenation of trichloroethene M. Azizian, I. Marshall, S. Behrens, A. Spormann & L. Semprini

209

Increasing confidence in treatment performance assessment using a geostatistical approach Zuansi Cai & Ryan D. Wilson

213

Toward enhanced remediation methods using chaotic advection Michael G. Trefry, Guy Metcalfe, Daniel R. Lester, Alison Ord & Klaus Regenauer-Lieb

217

Applications and implications of direct groundwater velocity measurement at the centimetre scale J. F. Devlin, P. C. Schillig, I. Bowen, D. L. Rudolph, N. R. Thomson, G. P. Tsoflias & J. A. Roberts

221

Biosparging successfully limited fugitive VOCs while remediating residual weathered gasoline in a shallow sand aquifer C. D. Johnston, R. Woodbury, T. P. Bastow & Y. Geste

225

9 Natural Attenuation

Assessment of chlorinated ethenes biodegradation in an anaerobic aquifer by isotope analysis and microcosm studies Karin Ebert, Christine Laskov, Sebastian Behrens & Stefan Haderlein

231

Chlorine isotope fractionation of organic contaminants: added value for in situ assessment of natural attenuation processes Christoph Aeppli, Charline Wiegert,Henry Holmstrand & Örjan Gustafsson

235

Monitored natural attenuation of arsenic: promises and pitfalls from two case studies Janet G. Hering

239

Influence of natural attenuation and river fluctuations on benzene dispersion in an alluvial aquifer subject to strong interactions with surface water J. Batlle-Aguilar, S. Brouyère, A. Dassargues, B. Morasch & D. Hunkeler

243

Proving natural attenuation at a petroleum hydrocarbon contaminated site by high-resolution direct push measurements as a basis for reactive transport modelling Anita Peter, Benedict Miles & Georg Teutsch

247

Three-dimensional analytical models for isotope ratios in pollutant plumes of organic contaminants undergoing different biodegradation kinetics Patrick Höhener & Olivier Atteia

251

Design and evaluation of bench-scale tank experiments for the quantification of transverse dispersion using numerical simulations E. Ballarini, S. Bauer, C. Eberhardt, M. Rolle, P. grathwohl & C. Beyer

255

Two-dimensional flow-through experiments: versatile test systems for a combined investigation of transport and reactive processes in porous media M. Rolle, G. Chiogna, C. Eberhardt, C. Haberer, C. Griebler, O. A. Cirpka & P. Grathwohl

259

Boundary conditions for explosives degradation in a Quaternary aquifer A. Weber & S. Tränckner

263

Groundwater pollution potential of additives used in borehole heat exchanger fluids D. Ilieva, B. Morasch & S. B. Haderlein

267

MNA site investigations – comparison of conceptual approaches derived from virtual model scenarios and real site studies S. Grandel, D. Schäfer, S. Bauer, A. Dahmke & C. Beyer

271

Assessing of the effect of physical heterogeneity on single well tracer tests using imaging experiments G. L. Barns, R. D. Wilson & S. F. Thornton

275

Scaling kinetics of organic compounds degradation: laboratory values extended to field sites O. Atteia & A. Mangeret

279

Enhanced natural attenuation – determining the potential for reductive dechlorination in an oxic aquifer Daniel Buchner, Meenakshi Loganathan, Sebastian Behrens, Christine Laskov, Thomas Schöndorf & Stefan Haderlein

283

Determination of in situ biodegradation rates using 13C-labelled aniline Barbara Morasch, Patrick Höhener & Daniel Hunkeler

287

Compound specific C and N isotope analysis of negatively charged pesticides: on-injector derivatization/GC-IRMS versus LC-IRMS Sandra Reinnicke, Anat Bernstein & Martin Elsner

291

Natural attenuation of gasoline hydrocarbons from residual sources containing ethanol Juliana G. Freitas, Marian T. Mocanu, José Luiz G. Zoby, John W. Molson & James F. Barker

295

10 Protecting and Managing Groundwater Quality

Application of groundwater life expectancy in the delineation of time-dependent capture zones for water supply wells J. W. Molson & E. O. Frind

301

Geometry of well capture zones in fractured media: uncertainties using an equivalent porous media approach Martí Bayer-Raich, Jerker Jarsjö & Salvador Jordana

305

Risk analysis for riverine groundwater extraction R. M. Page, P. Huggenberger, J. Epting & G. Lischeid

309

Using probabilistic well vulnerability criteria for a risk-based preventive drinking water safety concept Rainer Enzenhoefer, Wolfgang Nowak & Rainer Helmig

314

Nationwide characterisation of buffering capacities and background compositions of groundwater aquifers in the Netherlands Jasper Griffioen, Janneke Klein & Ruth Heerdink

318

Capture probability maps for addressing uncertainty: protection vs mitigation Marcelo R. Sousa, Emil O. Frind & David L. Rudolph

322

Assessing the impact of PrefaceBeneficial Management Practices for controlling nitrate concentrations in well water R. Rahman, E. O. Frind & D. L. Rudolph

326

Leaching of trace elements from a clay till aquitard by seepage from an oil sands tailings facility A. A. Holden, S. E. Haque, R. B. Donahue & A. C. Ulrich

330

Modelling nitrate dynamics in the well catchment Baltenswil (Zurich, Switzerland) Fritz Stauffer & Sebastian Stoll

334

Application of an agronomic model to determine optimal management strategies to reduce nitrate concentrations in groundwater S. Peña-Haro, M. Pulido-Velazquez, H. Yang, J. Liu & C. Llopis-Albert

338

A method for standardising groundwater nitrate concentrations A. Vrijhoef & L. J. M. Boumans

342

Guidelines for optimal design of electron acceptor injection wells to enhance bioremediation of contaminated groundwater Mohamed M. A. Mohamed

346

Fate of iodinated X-ray contrast media compounds under aerobic and anaerobic groundwater conditions B. M. Patterson, M. Shackleton, A. J. Furness & F. Busetti

350

Vulnerability zones to nitrate pollution in an Alpine region (South Tyrol, Italy) Roberta Bottarin, Uta Schirpke & Ulrike Tappeiner

354

Nitrogen leaching to groundwater and surface water in the Dutch peat region A. E. J. Hooijboer & B. Fraters

358

Multivariate statistical approach to a hydrogeochemical characterization of the Virttaankangas aquifer, SW Finland Päivi Niemistö & Kirsti Korkka-Niemi

362

Modern groundwater management: measures undertaken at the source – pilot project nitrate reduction in Klettgau SH Kurt Seiler, Iwan Stössel, Roger Biedermann & Markus Boller

367

Groundwater quality in Dutch water management Hilde F. Passier, Ruth Heerdink, Joachim Rozemeijer, Ate Visser, Yan-Chun Zhang, Stefan Jansen & Victor Beumer

371

The role of permeability distribution on nitrate fate and transport, in different scale experiments under saturated conditions M. Mastrocicco, N. Colombani & G. Castaldelli

375

Application of multivariate analytical methods in assessment of factors responsible for waterborne Kashin-Beck disease in Sichuan, China Xinxin Guo, Yiqun Gan & Yanxin Wang

379

Risk-based prioritisation of point sources through assessment of the impact on a water supply Niels D. Overheu, Mads Troldborg, Nina Tuxen, John Flyvbjerg, Henrik Østergaard, Carsten B. Jensen, Philip J. Binning & Poul L. Bjerg

383

Decision analysis to minimize agricultural groundwater demand and salt water intrusion using treated wastewater Ahmed Al-Juaidi, Ungtae Kim & Jagath J. Kaluarachchi

387

Passive samplers for monitoring VOC in groundwater: prospects related to mass flux measurements G. Verreydt, J. Bronders, I. Van Keer, L. Diels & P. Vanderauwera

391

11 Processes at Groundwater–Surface Water Interfaces

Do variable hydrologic and redox conditions influence organic pollutants in the streambed? C. Schmidt & E. Kalbus

397

Assessing groundwater travel times and biogeochemical processes during riverbank filtration under the aspect of river restoration T. Vogt, P. Schneider, S. Peter, E. Durisch-Kaiser, M. Schirmer & O. A. Cirpka

401

Experimental investigation of evaporation and condensation in sandy soils under simulated arid conditions E. Shimojima, I. Tamagawa & J. V. Turner

405

Effect of an artificial flood wave on groundwater in the hyporheic zone Stefan Banzhaf, Traugott Scheytt, Reinhard Bierl & Andreas Krein

410

Spatial characterization of hydraulic conductivity in alluvial gravel-and-sand aquifers: a comparison of methods S. Diem, T. Vogt & E. Hoehn

414

Field study and iron reactive simulation in riverbank water supply well fields Ekaterina Kazak, Sergey Pozdniakov & Natalia Muromec

419

Hydrogeochemical and isotopic indications of groundwater–surface water interactions at Lake Pyhäjärvi, SW Finland Kirsti Korkka-Niemi, Anne Rautio, Päivi Niemistö & Juha A. Karhu

423

Monitoring of change of the chemical composition of groundwater during vegetation periods Inom Normatov, Muslima Kholmirzoeva & Nabi Nosirov

427

12 Biogeochemical Interactions

Denitrification hot spot and hot moments in a restored riparian system Simone Peter, Romana Rechsteiner, Moritz F. Lehmann, Klement Tockner, Tobias Vogt, Bernhard Wehrli & Edith Durisch-Kaiser

433

Identifying biogeochemical processes beneath stormwater infiltration ponds in support of a new best management practice for groundwater protection Andrew M. O’Reilly, Ni-Bin Chang, Martin P. Wanielista & Zhemin Xuan

437

Reactive transport upscaling of small reactive heterogeneities for regional modelling David Rodríguez Aguilera, Johan R. Valstar & Jasper Griffioen

441

Use of chemical and biological techniques in the remediation of sites contaminated by chlorinated solvents D. Puigserver, J. M. Carmona, J. Barker, A. Cortés, X. Nogueras & M. Viladevall

445

13 Vadose Zone Processes

Modelling hydrologic and geochemical filtering of reactive solute transport in catchments P. S. C. Rao, N. B. Bas, S. Zanarado, C. J. Harman, M. Sivapalan & A. Rinaldo

451

Comparison of gasoline spills with different ethanol fractions Juliana G. Freitas, John D. Mosquera, Anthony L. Endres & James F. Barker

455

Reactive transport column experiment in volcanic ash soil and numerical modelling with anion and cation exchange reactions K. Nakagawa, S.-I. Wada & K. Momii

459

Laboratory experiments to determine oxygen transport in a fluctuating capillary fringe C. M. Haberer & P. Grathwohl

463

14 Contaminant Dynamics in Karst Systems

Estimation of nitrate discharge in a fractured limestone aquifer below a dairy farm in Ireland Florian Landig, Owen Fenton, Paul Bons, Deirdre Hennessy, Karl Richards & Philipp Blum

469

Towards developing conceptual models for reactive contaminant transport in karst Michael Sinreich

473

Particle density distribution measurements to control water quality of karst springs Dominik Baenninger, Adrian Auckenthaler & Nicole Itin

477

Estimating the vulnerability of karst springs to microbial contamination based on numerical flow modelling Christoph Butscher, Adrian Auckenthaler, Stefan Scheidler & Peter Huggenberger

481

15 Salinization of Groundwater Resources

Development of groundwater salinity in the Wadi Zerka Ma’in catchment area, Dead Sea, Jordan Taleb Odeh, Stefan Geyer, Mario Schirmer, Tino Rödiger, Christian Siebert & Richard Gloaguen

487

Modelling and controlling of groundwater and salt movement in Yanqi basin, northwestern China Shuixian Wang, Xinguang Dong & Bing Wu

491

Groundwater as a driver of salinity in the Wybong Creek catchment, New South Wales, Australia J. F. Jasonsmith, B. C. T. Macdonald, D. C. Mcphail, S. Beavis, I. White, F. Biswas & M. Norman

496

16 Groundwater Ecosystems

Assessment of groundwater quality in parts of the basement complex terrain of southwestern Nigeria Abel O. Talabi & Moshood N. Tijani

501

Key word index 507

GQ10: Groundwater Quality Management in a Rapidly Changing World (Proc. 7th International Groundwater Quality Conference held in Zurich, Switzerland, 13–18 June 2010). IAHS Publ 342, 2011, 3-6.

Groundwater quality, climate and irrigation: large-scale, long-term trends in the Aral Sea Drainage Basin

JERKER JARSJÖ & REBECKA TÖRNQVISTDepartment of Physical Geography and Quaternary Geology, Stockholm University, SE-106 91 Stockholm, [email protected]

Abstract We consider contaminant spreading under changing ambient conditions in the Aral Sea Drainage Basin (ASDB) in Central Asia, synthesising data on water-borne contaminants that occur at hazardously high concentrations. The basin has undergone an enormous irrigation expansion. Furthermore temperatures have increased by about 1C during the 20th century, and are expected to continue to increase in the near future. Results show that high concentrations of chromium, lead and copper in groundwater systems of ASDB constitute a considerable health hazard. However, in adjacent surface water systems, concentrations of the same contaminants are much lower. If downstream surface water resources dry up due to climate changes or continued upstream irrigation expansion, polluted groundwater can become the only remaining source for drinking water supply.Key words groundwater quality; climate change; irrigation expansion; large-scale trends


Climate change impact on the leaching of a heavy metal contamination in a small lowland catchment

ATE VISSER1, JOOP KROES2, MICHELLE VAN VLIET2, STEPHEN BLENKINSOP3 & HANS PETER BROERS1

1 Deltares, Princetonlaan 6, PO Box 85467, 3508 AL Utrecht, The [email protected] Wageningen University and Research Centre, Droevendaalsesteeg 4, PO Box 47, 6700AA Wageningen, The Netherlands3 Water Resource Systems Research Laboratory, School of Civil Engineering and Geosciences, Cassie Building, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK

Abstract The objective of this study was to assess the potential effects of climate change on the transport of pre-existing spatially-extensive trace metal contamination to a small lowland catchment in the south of the Netherlands. The area surrounding the Keersop has been contaminated with heavy metals by the atmospheric emissions of four zinc ore smelters. This heavy metal contamination, e.g. with Cd and Zn, has accumulated in the topsoil and leaches towards surface water system, especially during high groundwater levels and high discharge rates. Simulated projections of future climate predict increased precipitation in winter, less precipitation in summer, and higher air temperatures throughout the year. These climate change scenarios projected lower groundwater levels and lower discharge rates. As a result of

1

lower groundwater levels, transport of Cd and Zn towards surface water is also projected to decrease in the future climate. These results indicate a positive effect of climate change on a limited aspect of surface water quality.Key words climate change; surface water quality; heavy metal contamination; future climate scenarios


Groundwater characteristic of the Najd aquifers, Oman, derived from isotope and hydrochemical signatures

K. AL-MUSHAIKHI P

1,3P, G. STRAUCHP

1P, K. OSENBRÜCKP

2P, T. MÜLLERP

1P, K.

KNÖLLERP

2P & S. OSWALDP

4P

1 Helmholtz Centre for Environmental Research – UFZ, Department of Hydrogeology, Permoserstraβe 15, 04318 Leipzig, GermanyHTU [email protected] UTH

2 Helmholtz Centre for Environmental Research – UFZ, Department Isotope Hydrology, Theodor-Lieser-Straße 4, 06120 Halle/Saale, Germany3 Ministry of Regional Municipality & Water Resources, Salalah, Sultanate of Oman4 University of Potsdam, Institute for Earth Sciences, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany

Abstract Groundwater in the Najd region of Oman is more or less the only water resource for farming, housing, and animal feeding. Increasing efforts for a sustainable use of this groundwater needs to improve the knowledge about the origin, distribution, and recharge of the resource. The multi-component approach of the application of hydrochemical and isotope methods supports the complex understanding of the groundwater evolution in the four main aquifers A–D of the Najd region. The study reviews the hydrogeochemical character and a differentiated signature of the water isotopes P2PH, P18PO, and P3PH in all Najd aquifers from A to D. It focuses on the groundwater chemical and isotopic behaviour, and the relationship between aquifers. The Najd groundwater is classified mainly as Na-Ca-Mg-SOB4B-Cl, however, varying between the aquifers from A to D. The stable water isotopes P2PH and P18PO as well as tritium refer to the different recharge conditions in the past and recent infiltration processes including mixing of paleo-/sub-modern to recent groundwater between the aquifers. A hypothesis about origin and hydrochemical characteristic of groundwater from the Najd region is derived from the hydrochemical and isotope data from this study.Key words environmental isotopes; groundwater; hydrochemistry; Najd aquifers, Oman; water quality


mailto:[email protected]

Incorporating groundwater quality in the water-supply and sanitation sector development program for Bangladesh

KAZI MATIN AHMED1 & PETER RAVENSCROFT2

1 Department of Geology, University of Dhaka, Dhaka 1000, Bangladesh [email protected] AMEC Entec, Cambridge Business Park, Cambridge CB4 0WZ, UK

Abstract In 2005, the government of Bangladesh adopted a Sector Development Program (SDP) to provide water supply and sanitation for all. In Bangladesh water supplies are drawn mainly from shallow and deep alluvial aquifers. A shift to groundwater in the 1970s was orchestrated to reduce the burden of diarrhoeal disease from polluted surface water. Historically, groundwater quality has been neglected, but subsequent surveys have found exceptional levels of As pollution, as well as contamination by Mn, Fe, B, Ba, Cl and U. There are also growing risks from agricultural and industrial chemicals, and waste disposal. Shallow aquifers are at high risk from arsenic and anthropogenic contaminants. The deep aquifer is currently safe in this respect, but its sustainable yield is uncertain. Implementing sector policies for quality and quantity requires major investment in resource investigation and development, water treatment, and institution building.Key words groundwater; water quality; national; local; management; Bangladesh


Optimal fertilizer control for meeting EU groundwater nitrate concentration standards: El Salobral-Los Llanos case study

S. PEÑA-HARO1,2, M. PULIDO-VELAZQUEZ2 & C. LLOPIS-ALBERT2 1 Institute of Environmental Engineering, ETH Zurich, HIL G33.3, Wolfgang-Paulistrasse 15, CH-8093 Zürich, [email protected] Department of Hydraulics and Environmental Engineering, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022, Valencia, Spain

Abstract High nitrate concentration in groundwater deteriorates water quality, restricts its use for drinking water supply, and causes economic and environmental impacts. Although the legislation on groundwater quality refers to the pollutant concentration, the effects of most measures on groundwater quality are often evaluated in terms of their potential for emission reduction at the source. A hydro-economic modelling framework is used for determining the most cost-efficient management of fertilizer in agriculture that meets EU groundwater nitrate pollution standards for agricultural basins. Agronomic simulations are used to obtain crop yields and nitrate leaching, while numerical groundwater flow and solute transport simulation models were used to develop unit source solutions that were assembled into a pollutant concentration response matrix. The benefits in agriculture were determined through crop prices and crop production functions. The methodology was applied to El Salobral-Los Llanos

aquifer, located in the southeast of the Mancha Oriental aquifer system (Spain), which extends over 421 km2. The main land use is agriculture. Nitrate concentrations fluctuate from 18.7 to 54.1 mg/L, exceeding the allowed concentration for human consumption. The hydro-economic model shows the spatial fertilizer application rate that minimizes income losses in agriculture constrained by groundwater quality requirements at the wells for drinking water supply. Key words groundwater nitrate pollution; management; optimal fertilizer; hydro-economic modelling


Large-scale modelling of groundwater resources in an arid region

EDDA KALBUS1, SASCHA OSWALD1,2, WENQING WANG3, OLAF KOLDITZ3, IRINA ENGELHARDT4, MOHAMMED I. AL-SAUD5 & RANDOLF RAUSCH6

1 Helmholtz Centre for Environmental Research – UFZ, Department of Hydrogeology, Permoserstr. 15, 04318 Leipzig, Germany [email protected] University of Potsdam, Institute for Geoecology, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany3 Helmholtz Centre for Environmental Research – UFZ, Department of Environmental Informatics, Permoserstr. 15, 04318 Leipzig, Germany4 Technical University of Darmstadt, Institute for Applied Geosciences, Schnittspahnstr. 9, 64287 Darmstadt, Germany5 Ministry of Water & Electricity, Riyadh, Kingdom of Saudi Arabia6 GTZ International Services, PO Box 2730, Riyadh 11461, Kingdom of Saudi Arabia

Abstract In arid regions, the available water resources are largely restricted to groundwater. Therefore, a precise quantification of the available groundwater resources, including groundwater recharge, is essential for the management of the limited water resources. For a consistent assessment and the analysis of future exploitation scenarios, numerical modelling is a helpful tool. Our approach is to combine information and process knowledge from various backgrounds to simulate the development of the current situation during the last millennia and account for complex boundaries and spatial variability. The model represents the Upper Mega aquifer system in the eastern part of Saudi Arabia, which consists of several coupled aquifers, as first data analyses results indicate. Due to the size of the model region and the required model precision, sophisticated modelling systems and large computational resources are required. The model may serve as a prognostic tool for an Integrated Water Resources Management.Key words groundwater modelling; groundwater recharge; arid regions; OpenGeoSys; data management system


Eighty-year variability in rainfall in northern Nigeria and its effect on aquifer recharge

S. A. AYANLAJAOlabisi Onabanjo University, Ago-Iwoye, Nigeria

[email protected]

Abstract The northern part of Nigeria above latitude 11° falls in the Sudan Savanna and Sahel zones, with some 30 million people, mostly farmers growing rain fed millet sorghum, and grass for ruminant animals. The agrarian and semi-nomadic communities source domestic water from seasonal brooks, rivers and hand dug wells. The study seeks to understand the relationship between rainfall quantity and groundwater recharge, and therefore is able to predict quantity of water obtainable in these cisterns. Annual rainfall data collected from weather stations, as reported in various secondary sources for the four principal towns in the region: Sokoto, Kano, Katsina and Maiduguri for a period of 80 years (1920–2000), were analysed in comparison with rate of changing water levels in the hand dug wells in Mulgwe in the Chad basin. In all the stations, rainfall gently oscillated around the mean during the period 1920 and 1960 after which it started to dramatically decrease. Thus, average rainfall in Maiduguri during the periods 1920–1960, and 1965–2000 were 832.4 and 554.0 mm, respectively. Water level measurements in Mulgwe hand dug wells in the Chad basin between 1964 and 1973 show that water level reduced by as much as 735 cm within the 10-year period. Regression analysis between annual rainfall and yearly water level decline in the well shows r = 0.634, thus revealing a close association between these factors. There is therefore a need to mitigate climate change by reducing the prevalent deforestation and the continuous gas flaring in Nigeria.Key words groundwater; climate change, deforestation; gas flaring


Methodologies and tools for the estimation of mass fluxes of xenobiotics at different scales in urban areas

FRIDO REINSTORF1, SEBASTIAN LESCHIK2, ANDREAS MUSOLFF2, HANS-REINHARD GLÄSER2, KARSTEN OSENBRÜCK3, MONIKA MÖDER4, GERHARD STRAUCH2 & MARIO SCHIRMER5

1 University of Applied Sciences Magdeburg-Stendal, Department of Water Resources and Waste Management, Breitscheidstr. 2, 39114 Magdeburg, [email protected] Helmholtz Centre for Environmental Research – UFZ, Department Hydrogeology, Permoserstr. 15, 04318 Leipzig, Germany3 Helmholtz Centre for Environmental Research – UFZ, Department Isotope Hydrology, Theodor-Lieser-Str. 4, 06120 Halle, Germany4 Helmholtz Centre for Environmental Research – UFZ, Department Analytics, Permoserstr. 15, 04318 Leipzig, Germany5 EAWAG - Swiss Federal Institute of Aquatic Science and Technology, Department Water Resources and Drinking Water, Ueberlandstraße 133, 8600 Duebendorf, Switzerland

Abstract In the context of sustainable urban water management, the estimation of mass fluxes plays a fundamental role in the assessment of the anthropogenic impacts of xenobiotics in urban water systems. Numerous well-known methods exist for parameter estimation and process identification in aquifers and surface waters. Thus, the need has evolved for appropriate applicable methods especially for urban areas. This article provides an overview of new and known methods that are applied in our investigations for estimating fluxes within and between different compartments which are influenced by urban sewer systems. Multiple-scale approaches combining measuring and modelling methods to estimate the mass fluxes on a large (>100 km2) and medium (<10 km2) scale are discussed. Additionally, methods are considered that allow the quantification of interaction processes between the compartments on a small (<1000 m2) scale.Key words urban areas; xenobiotics; modelling; integral pumping test; passive sampler


Investigation and modelling of the degradation during rapid sand filtration and redox sensitivity of the industrial contaminant p-TSA

R. MEFFE1, G. MASSMANN2, C. KOHFAHL3, T. TAUTE1, E. HOLZBECHER4, D. RICHTER5 & U. DÜNNBIER6 1 Institute of Geological Sciences, Free University Berlin, Malteserstr. 74-100, 12249 Berlin, [email protected] Institute of Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, D-26111 Oldenburg, Germany3 Instituto Geológico y Minero, Pza. de España–Torre Norte, 41013 Sevilla, Spain4 Georg-August-Universität Göttingen, GZG, Goldschmidtstr. 3, 37077 Göttingen, Germany5 DVGW-Technologiezentrum Wasser (TZW), Karlsruher Straße 84, 76139 Karlsruhe, Germany6 Department of Laboratories, Berliner Wasserbetriebe, 10864 Berlin, Germany

Abstract A finite element model was set up to determine degradation rate constants for p-TSA during rapid sand filtration (RSF). Data used for the model originated from a column experiment carried out in the filter hall of a drinking water treatment plant in Berlin (Germany). Model results were fitted to measured profiles and breakthrough curves of p-TSA for different infiltration rates using both first-order reaction kinetics and Michaelis-Menten kinetics. Both approaches showed that degradation rates varied both in space and time. Higher degradation rates were observed in the upper part of the column, probably related to higher microbial activity in this zone. Measured and simulated breakthrough curves revealed an adaption phase with lower degradation rates after infiltration rates were changed, followed by an adapted phase with more elevated degradation rates. Irrespective of the mathematical approach and the infiltration rate, degradation rates were very high, probably owing to the fact that filter sands have been in operation for decades, receiving high p-TSA concentrations with the raw water. The persistence of p-TSA in the anoxic groundwater, p-TSA removal during aerated rapid filtration and results from incubation experiments, suggest that oxic conditions are essential for p-TSA degradation. Key words p-TSA; microbial degradation; reactive transport modelling; redox sensitivity



Optimal sampling schedules of integral pumping tests for the investigation of groundwater contamination from urban line sources

SEBASTIAN LESCHIK1, MARTI BAYER-RAICH2, ANDREAS MUSOLFF3 & MARIO SCHIRMER4

1 UFZ - Helmholtz Centre for Environmental Research, Department Groundwater Remediation, Permoserstrasse 15, 04318 Leipzig, Germany [email protected] 2 Amphos 21 Consulting S.L., Passeig de Rubi 29-31, 08197 Valldoreix Barcelona, Spain 3 UFZ – Helmholtz Centre for Environmental Research, Department Hydrogeology, Permoserstrasse 15, 04318 Leipzig, Germany4 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department Water Resources and Drinking Water, Ueberlandstrasse 133, 8600 Duebendorf, Switzerland

Abstract The integral pumping test method (IPT) can be used to investigate the spatial heterogeneous and temporal variable release of wastewater constituents from urban line sources (e.g. leaky sewers). Long-time pumping (several days) and simultaneous sampling yield concentration-time series that can be used for the evaluation of average concentration Cav

along control planes in an aquifer. The applied sampling schedules during IPT operations have an important influence on the accuracy of the Cav estimations. A detailed investigation of 30 high-frequency concentration-time series from two field sites in the city of Leipzig (Germany) was performed to optimize the number of samples and the sampling time of IPTs in the vicinity of urban line sources. The results show that IPTs with a low number of samples can also provide reliable Cav values. Concerning the optimal sampling times a sampling scheme with constant time intervals is preferable.Key words average concentration; integral pumping test; sampling schedule; urban line source


Manufactured nanoparticle movement in the groundwaters of a redbed sandstone: laboratory experiments and field observations

JOHN TELLAM1, RICHARD GRESWELL1, MICHAEL RILEY1 & SYED RAHMAN2 1 School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK [email protected]

2 Environmental Sciences, Jahangirnagar University, Dhaka 1342, Bangladesh

Abstract Production of manufactured nanoparticles (mNPs) is likely to increase significantly in the near future. To investigate mNP mobility in sandstone groundwaters, column experiments have been completed on intact continental redbed sandstone. SiO2 mNP breakthrough concentrations decrease as ionic strength increases, with reversibility indicating secondary minimum attachment: a maximum retention capacity is observed. In contrast, initial metal oxide mNP breakthrough concentrations in deionized water gradually fall as clogging occurs, mobility being in the order (Si >) Ti, Sb > Ce, Ag: no detectable breakthrough occurs for artificial groundwater solutions, even after many 100s of pore volumes. These results suggest that most particles have limited mobility, consistent with measured potentials, but that remobilization can occur if conditions change. A small proportion of particles appear to be more mobile, and this is confirmed by the presence of small amounts of mNPs in wellwaters. Key words manufactured nanoparticles; colloids; urban; groundwater


Dynamic plant uptake modelling and mass flux estimation

A. REIN, P. BAUER-GOTTWEIN & S. TRAPPDepartment of Environmental Engineering, Technical University of Denmark, Miljøvej, Bd. 113, DK-2800 Kgs. Lyngby, [email protected]

Abstract Plants significantly influence contaminant transport and fate. Important processes are uptake of soil and groundwater contaminants, as well as biodegradation in plants and their root zones. Models for the prediction of chemical uptake into plants are required for the set-up of mass balances in environmental systems at different scales. Feedback mechanisms between plants and hydrological systems can play an important role. However, they have received little attention to date. Here, a new model concept for dynamic plant uptake models applying analytical matrix solutions is presented, which can be coupled to groundwater transport simulation tools. Exemplary simulations of plant uptake were carried out in order to estimate chemical concentrations in the soil–plant–air system and the influence of plants on contaminant mass fluxes from soil to groundwater.Key words plant uptake; dynamic; analytical solution; mass fluxes; groundwater transport; coupling


Micropollutant mass flow in urban receiving waters

ANDREAS MUSOLFF1, SEBASTIAN LESCHIK2, GERHARD STRAUCH1 & MARIO SCHIRMER3

1 UFZ – Helmholtz Centre for Environmental Research, Department of Hydrogeology, Permoserstr. 15, 04318 Leipzig, Germany

[email protected] UFZ – Helmholtz Centre for Environmental Research, Department of Groundwater Remediation, Permoserstr. 15, 04318 Leipzig, Germany3 Eawag – Swiss Federal Institute of Aquatic Science and Technology, Department Water Resources and Drinking Water, Überlandstr, 133, 8600 Dübendorf, Switzerland

Abstract Urban water resources are frequently polluted by micropollutants originating from wastewater. Since the urban water cycle is characterized by complex interaction between surface water, groundwater and the wastewater system we applied an integral approach to quantify the annual micropollutant mass flow from an urban drainage area (sewershed). Over the course of one year, concentrations of several micropollutants were monitored in untreated and treated wastewater and in groundwater. In combination with models of annual urban water flow, micropollutant mass flow was derived. The mass release was highest for the treated wastewater pathway to the surface water. Nevertheless, through the pathway of combined sewer overflow (CSO) and groundwater discharge out of the sewershed boundaries a significant part of the annual mass flow was released. As a consequence, the mass release by CSO and groundwater discharge should be taken into account in micropollutant assessments.Key words urban hydrogeology; PPCP (pharmaceuticals and personal care products); sewer leakages; combined sewer overflow


Multi-chemical and isotope approach for studying shallow and deep groundwater interaction in an urban area: the case of Tivoli Plain (central Italy)

V. CARUCCI1, M. PETITTA1 & R. ARAVENA2

1 Department of Earth Sciences, University of Rome La Sapienza, P.le Aldo Moro 5, 00185 Rome, [email protected] 2 Department of Earth and Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L-3G1, Canada

Abstract Interaction between shallow and deep groundwater flow systems has been investigated by the means of chemical and isotopic tracers in the Tivoli Plain aquifer system (Rome, central Italy). During the last decade an intense activity in the travertine quarries in the Acque Albule basin has caused a significant drop in the water table of the shallow travertine aquifer. A multi-isotope approach was used to have a better understanding of interactions between shallow and deep aquifers, and to improve the knowledge of the conceptual hydrogeological model, which has implications for groundwater management in the Tivoli plain. The hydrochemistry of the travertine aquifer is characterized by a mixing between two end-members related, respectively, to groundwater coming directly from outcropping carbonate aquifers and to groundwater circulating in deep buried Meso-Cenozoic carbonate sequences. 18O and 13C isotope tracers are diagnostic for the geochemical mixing definition. Key words hydrochemistry; environmental isotopes; travertine; central Italy; mixing aquifer


Thermal groundwater use in urban areas – spatiotemporal scales and concepts

JANNIS EPTING, PETER HUGGENBERGER & CHRISTOPH BUTSCHERDepartment of Environmental Sciences, Applied and Environmental Geology, University of Basel,

Bernoullistr. 32, 4056 Basel, Switzerland [email protected]

Abstract Over the last few decades, the use of the urban subsurface and urban groundwater resources has increased significantly. The application of groundwater for process and cooling purposes in particular may result in considerable pressure on urban aquifers. Additionally, the extension of subsurface infrastructures and the diffuse heat input of heated buildings have resulted in elevated groundwater temperatures in many urban areas. Therefore, for the sustainable development of urban subsurface resources, adequate management approaches are required. This includes the development of tools that will facilitate investigation of groundwater and heat flow processes at relevant spatiotemporal scales. An approach is presented where data from high resolution depth-oriented temperature monitoring are incorporated into 3-D numerical models that facilitate the simulation of groundwater flow and thermal regimes. The results form the basis for the development of concepts for the use of the urban subsurface for specific aquifer regions and future use scenarios. Key words urban groundwater management; thermal groundwater use; vertical temperature monitoring


Groundwater quality of upper and lower Dupi Tila aquifers in the megacity Dhaka, Bangladesh

K. M. AHMED1, S. SULTANA1, M. A. HASAN1, P. BHATTACHARYA2, M. K. HASAN3, W. G. BURGESS3 & M. A. HOQUE3

1 Department of Geology, University of Dhaka, Dhaka 1000, Bangladesh [email protected] Department of Land and Water Resources Engineering, Royal Institute of Technology, Stockholm, SE-100 44, Sweden3 Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK

Abstract Dhaka is one of the fastest growing megacities of the world and is set to become the third largest by 2025. Currently about 86% of the municipal water supply comes from over 500 wells drilled in the Dupi Tila aquifers underlying the city. The Upper Dupi Tila aquifer

(UDTA) is overexploited and a large part has been dewatered; abstractions from the lower Dupi Tila started only recently. Results of water analysis and EC surveys have been used to decipher the variations in groundwater quality in the UDTA and LDTA. EC surveys reveal a systematic deterioration of water quality in the vicinity of the Buriganga River in southeast Dhaka. The UDTA is more widely affected by anthropogenic processes than the LDTA, which still largely exhibits its intrinsic water quality characteristics. Regular monitoring and proper management practices are essential to protect the quality of this precarious resource.Key words Dhaka megacity; urban; Dupi Tila aquifer; anthropogenic; pollution


Hydrochemical and microbiological assessment of groundwater from the weathered basement aquifer in Ibadan Metropolis, SW-Nigeria

MOSHOOD N. TIJANI1 & SEYBATOU DIOP2

1 Geology Department, University of Ibadan, Ibadan, Nigeria [email protected] 2 Institut des Sciences de la Terre, Université Cheikh Anta Diop de Dakar, BP 5396 Dakar-Fann, Sénégal

Abstract A hydrogeochemical study was carried out on the shallow groundwater system of the weathered regolith aquifer within Ibadan Metropolis, with the objective of determining geochemical characteristics as well as identifying the influence of household activities on both chemical and microbiological quality status. Hydrochemical analyses of water samples from 50 shallow dug-wells revealed total dissolved solids of 54–1055 mg/L (av. 373 mg/L) and dominance of Ca, Na and HCO3 as major ionic components, thereby suggesting a precipitation dominated low mineralized water system with limited residence time typical of a weathered crystalline bedrock setting. However, the total heterotrophic bacteria count (THBC) in the range of 20–3500 and coliform bacteria (E. coli) of 1–200 in some of the water samples alongside high NO3 concentration, is a clear indication of impacts of human waste inputs through in-house septic/soakaway pits. Key words basement aquifer; hydrochemistry; microbiological assessment; groundwater quality; urban anthropogenic impact


Assessment of groundwater vulnerability and quality under urban-industrial influence in a subtropical town of north India

D. C. SINGHAL, H. JOSHI & V. K. SHARMADepartment of Hydrology, Indian Institute of Technology Roorkee, Roorkee 247667, India

[email protected]

Abstract The growth of urban settlements and industrial activities, along with increasing demands for various water uses, are causing considerable stress on the water supplies worldwide. The present study examines the impact of urbanization and industrial development on the shallow groundwater regime in a subtropical town (Saharanpur) of north India where the major source of water supply for drinking is from shallow hand pumps and tubewells tapping alluvial aquifers. Many of the industrial units of the town discharge waste effluents directly into the nearby drains. The assessment of groundwater vulnerability by using the well known DRASTIC Index approach has indicated that many central and southern localities of the town are threatened by pollution. This is corroborated by the analysis of groundwater samples wherein parameters like faecal coliforms, cadmium, chromium, nitrates and sulphate occur in high concentrations. For future protection of groundwater, 11 additional well locations have been identified for quality monitoring.Key words groundwater; protection; Saharanpur; alluvial aquifer; vulnerability; north India


Societal costs for remediation of an MTBE groundwater contamination by air stripping

MARIO SCHIRMER1 & HORST NIEMES2

1 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department Water Resources and Drinking Water, Ueberlandstr. 133, 8600 Duebendorf, [email protected] 5 Helmholtz Centre for Environmental Research – UFZ, Department of Hydrogeology, Permoserstraβe 15, 04318 Leipzig, Germany

Abstract The case study deals with the long-term contamination problem of the Leuna aquifer. The contamination can only be solved using external technological intervention because the aquifer has an extraordinarily low natural attenuation capability for the specific pollutants. Due to the longevity of the contamination source, the groundwater treatment technique that was chosen for the site must operate for at least 30 years. Since the polluter-pay-principle cannot be applied, the estimated dynamic prime costs for solving this problem must be understood as costs for a political decision, which have to be paid for by current and future generations, and are quite high in comparison to the water production costs of the downstream Daspig water works.Key words groundwater contamination; MTBE-remediation techniques; costs for groundwater treatment


Simulation of the impact of the South to North Water Transfer Project on groundwater in the Beijing plain

YANG YONG1, LI GUO-MIN1, DONG YAN-HUI1, LI MING1, YANG JIANG-QING2, ZHOU DONG3 & YANG ZHONG- SHAN3

1 Institute of Geology and Geophysics Chinese Academy of sciences, Beijing 100029, [email protected] Ministry of Water Resources, Department of Hydrological Analysis, Beijing 100053, China3 Beijing Hydraulic Center, Beijing 100039, China

Abstract In the Beijing plain, the groundwater level has been gradually descending due to extensive groundwater pumping in consecutive drought years. With the implementation of the South to North Water Transfer Project, an opportunity has been provided for restoration of groundwater under over-exploitation state. On the basis of hydrogeology conditions of the Beijing plain, as well as the high performance parallel computing platforms, a numerical groundwater flow model was established. The results show that several obvious depression cones of groundwater have been formed because of the rapid decline of groundwater levels in the Beijing plain in recent years. After the implementation of the South to North Water Transfer Project and due to the restrictions on groundwater exploitation, the area of the cone of depression will be reduced to different degrees, and the centre level of depression cone will rise up. It is a benefit to relieve water shortage and control the development of land subsidence and the deterioration of the ecological environment.Key words South to North Water Transfer Project; groundwater dynamic change; Beijing plain; numerical model; parallel computing


Reasonable exploitation of groundwater based on numerical simulation in Pinggu basin, Beijing, China

HAI-ZHEN XU1, GUO-MIN LI1, SHOU-QUAN ZHANG2, YAN-HUI DONG1 & MING LI1

1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, [email protected] Beijing Water Authority, Beijing, 100038, China

Abstract Beijing is facing a serious water crisis because of an unprecedented economic and population boom. Two well fields were built in Pinggu basin, Beijing east, to ease the water pressure before water diversion of the South-to-North Water Diversion Project. In order to study the influence of the huge quantity of extraction in the Pinggu basin, a 3-D transient groundwater flow model was developed and several scenarios were simulated in the prediction periods. By analysing the simulation results, some useful conclusions were reached, which


http://dict.cnki.net/dict_result.aspx?searchword=%E6%B0%B4%E6%96%87&tjType=sentence&style=&t=hydrological+analysis

could be used for groundwater management and pumping strategies for the long-term sustainability of groundwater.Key words groundwater; numerical model; scenario analysis; well field


A new approach for calculating the predicted environmental concentration of human pharmaceuticals in groundwater at bank filtration sites

BEATE MÜLLER1, TRAUGOTT SCHEYTT1, MATTHIAS ZIPPEL2, STEPHAN HANNAPPEL2, JUTTA KLEIN-GOEDICKE3 & KLAUS DUSCHER2

1 Technische Universität Berlin, Department of Applied Geosciences, Hydrogeology Research Group, Ackerstraße 71-76, 13355 Berlin, Germany [email protected] HYDOR Consult GmbH, Am Borsigturm 40, 13507 Berlin, Germany3 Federal Environment Agency, Wörlitzer Platz 1, 06844 Dessau, Germany


The artificial sweetener acesulfame as marker of domestic wastewater in groundwater

IGNAZ J. BUERGE1, HANS-RUDOLF BUSER1, MAREN KAHLE2, MARKUS D. MÜLLER1 & THOMAS POIGER1

1 Agroscope Changins-Wädenswil Research Station ACW, Plant Protection Chemistry, Schloss, 8820 Wädenswil, [email protected] Umweltbundesamt, PO Box 1406, 06813 Dessau-Rosslau, Germany

Abstract To assess sources and magnitude of possible groundwater contamination, chemical markers have proved to be useful. A chemical that is used in everyday life, the artificial sweetener acesulfame, may be ideally suited for detection of traces of domestic wastewater in natural waters. The compound was found ubiquitously in wastewater, surface waters, and groundwater from Switzerland. Acesulfame was not eliminated in wastewater treatment plants (WWTPs), and was quite persistent in lakes, where concentrations increased with population in the catchment area and decreased with water throughflow. Highest concentrations in groundwater were observed in areas with significant infiltration of river water, where the infiltrating water received considerable discharges from WWTPs. Given the currently achieved


detection limit of approx. 0.01 µg/L, the presence of ≥0.05% wastewater can be traced in groundwater.Key words chemical marker; domestic wastewater; groundwater; artificial sweeteners


Laboratory simulated transport of microcystin-LR and cylindrospermopsin in groundwater under the influence of stormwater ponds: implications for harvesting of infiltrated stormwater

ANDREW M. O’REILLY1, MARTIN P. WANIELISTA2, KEITH A. LOFTIN3 & NI-BIN CHANG4

1 US Geological Survey, Florida Water Science Center, 12703 Research Pkwy, Orlando, Florida 32826, [email protected] University of Central Florida, Water Research Center and Stormwater Management Academy, 4000 Central Florida Blvd, Building 91, Suite 442, Orlando, Florida 32816, USA3 US Geological Survey, Organic Geochemistry Research Laboratory, 4821 Quail Crest Place, Lawrence, Kansas 66049, USA4 University of Central Florida, Department of Civil, Environmental, and Construction Engineering, 4000 Central Florida Blvd, Building 91, Suite 442, Orlando, Florida 32816, USA

Abstract Water shortages in the southeastern United States have led to a need for more intensive management and usage of stormwater for beneficial uses such as irrigation. Harvesting of infiltrated stormwater from horizontal wells in sandy aquifer sediments beneath stormwater ponds has emerged as an alternative in need of evaluation. Cyanobacteria may proliferate in stormwater ponds; cyanotoxins produced by these organisms represent potential public health concerns. Results of two, saturated flow, sand column experiments indicate breakthrough of microcystin-LR (MCLR) and cylindrospermopsin (CYL) within 1–2 pore volumes indicating little removal attributable to sorption. Concentration-based MCLR removal efficiencies up to 90% were achieved, which we hypothesize were predominantly due to biodegradation. In contrast, CYL removal efficiencies were generally less than 15%. On the basis of these results, removal of sandy soil in the stormwater pond bottom and addition of sorption media with greater binding affinities to cyanotoxins may enhance natural attenuation processes prior to water withdrawal.Key words cyanotoxin; natural attenuation; ELISA; stormwater management; water harvesting


Perfluorinated chemicals in Swiss groundwater – results of

the National Groundwater Monitoring NAQUA

MIRIAM REINHARDT1, RONALD KOZEL1, STEPHANIE ZIMMERMANN1, HEINZ RUPP2, OTMAR ZOLLER2 & EDUARD HOEHN3

1 Swiss Federal Office for the Environment FOEN, CH-3003 Bern, [email protected] 2 Swiss Federal Office of Public Health FOPH, CH-3003 Bern, Switzerland3 Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland

Abstract Perfluorinated chemicals (PFC) are the subject of increasing public concern. Due to their hydro- and oleo-phobic properties, they are used in diverse industrial processes, and occur in several consumer products. The thermal and chemical stability of certain PFC has resulted in their global distribution in the environment. In a pilot study of the Swiss National Groundwater Monitoring NAQUA, PFC were detected at 21 of 49 sampled NAQUA monitoring sites. Except for one monitoring site, concentrations were below 100 ng/L, in most cases even below 10 ng/L. The highest concentrations were generally recorded for Perfluoroctanesulfonate (PFOS). All monitoring sites at which PFC were detected are situated in unconsolidated aquifers along rivers. The discharge of treated or untreated wastewater into rivers and streams and the subsequent infiltration of these waters into groundwater appear to be the major source of PFC in Swiss groundwater. Key words perfluorinated chemicals; groundwater monitoring; NAQUA; PFOS; Switzerland


Investigations of industrial waste migration in heterogeneously layered medium

JULIA V. FEDOROVA & ALEXEY V. LEKHOVMoscow State University, Geological Faculty, Department of Hydrogeology, Leninskie Gory 1, 119234 Moscow, Russiajuliafedor @mail.ru

Abstract A model for radioactive waste (RAW) migration in heterogeneously layered media taking account diffusion, sorption and complexing, was developed. The model was applied to liquid RAW deep disposal of the Siberian Chemical Complex (Tomsk, Russia). Waste is injected into permeable sandy layers (channels), divided by poorly-permeable clayey layers (blocks). In the model view, the industrial waste is a solution of the basic salt (NaNO3) and the micro salts (nitrates of Cs and Sr). The solution contains both stable and radioactive isotopes of strontium and caesium. The groundwater is fresh; its composition is presented by the macro salt and natural isotopes of the radionuclides. The theory of Onsager is used for diffusion calculation. The simulation shows that low concentrations of the radionuclides are transported along a channel with almost the same velocity as the macro components. We found, that the radionuclides diffusion into blocks will be minimal, if they occur under natural conditions. In the case of mutual diffusion and sorption of the isotopes as one chemical agent, clayey blocks “shut” due to macro salt diffusion and the radionuclides do not penetrate into them.


Key words multicomponent diffusion; waste migration; radionuclides; modelling


Long-term natural attenuation of crude oil in the subsurface

BARBARA BEKINS1, MARY JO BAEDECKER2, ROBERT P. EGANHOUSE2

& WILLIAM N. HERKELRATH3

1 US Geological Survey, MS 496, 345 Middlefield Rd., Menlo Park, California 94025, [email protected] US Geological Survey, MS 432, 12201 Sunrise Valley Dr., Reston, Virginia 20192, USA3 US Geological Survey, MS 496, 345 Middlefield Rd., Menlo Park, California 94025, USA

Abstract The time frame for natural attenuation of crude oil contamination in the subsurface has been studied for the last 27 years at a spill site located near Bemidji, Minnesota, USA. Data from the groundwater contaminant plume show that dissolved benzene concentrations adjacent to the oil decreased by 50% between 1993 and 2007. To assess how this decrease is related to benzene concentrations in the crude oil, samples of oil were bailed from floating oil in five wells and analysed for volatile components. Compared to reference oil collected from the pipeline in 1984, benzene concentrations in the well located farthest downgradient in the oil have decreased an average of 50%. Benzene and ethylbenzene depletion are linearly correlated with oil saturation in the pore space suggesting that dissolution is the primary removal mechanism and biodegradation within the oil body is insignificant.Key words petroleum; benzene; methanogenic; biodegradation


Simulation of DNAPL distribution depending on groundwater flow velocities using TMVOC

KATHARINA ERNING1, DIRK SCHÄFER1, ANDREAS DAHMKE1, ANTONELLA LUCIANO2, PAOLO VIOTTI2 & MARCO PETRANGELI PAPINI3

1 Dept. of Applied Geology, Christian-Albrechts-University Kiel, Ludewig-Meyn-Strasse 10, 24118 Kiel, [email protected] Dept. of Hydraulics, Transportations and Roads, Sapienza University of Rome, Via Eudossiana 18, 00184 Roma, Italy3 Dept. of Chemistry, Sapienza University of Rome, P. le Aldo Moro 8, 00185 Roma, Italy

Abstract Remediation actions on groundwater contaminations are based on the knowledge of

the position, the size and the mass of the source zone. We focus in our research on the question, whether high groundwater flow velocities can cause a displacement of a DNAPL source zone. Additionally, the impact of high groundwater flow velocities on the development of the DNAPL body is investigated. The tool for these investigations is multiphase modelling of different flow scenarios with TMVOC. The simulation revealed that even low groundwater flow velocities affect the DNAPL movement and distribution in the saturated zone and should thus be taken into account by site investigation.Key words DNAPL infiltration; lateral displacement; groundwater flow velocities; multiphase flow modelling; TOUGH; TMVOC


Source functions for multi-component DNAPLs based on streamtube analysis

MICHAEL C. BROOKS1, A. LYNN WOOD1 & JAMES W. JAWITZ2

1 US EPA, Office of Research and Development, National Risk Management Research Laboratory, GWERD, Ada, Oklahoma 74820, [email protected] University of Florida, Soil and Water Science Department, Gainesville, Florida 32611, USA

Abstract The purpose of this work is to investigate source functions for multi-component DNAPLs under heterogeneous conditions using a streamtube approach. Heterogeneity in the hydraulic conductivity field is represented by a collection of streamtubes with a distribution of travel times, and the DNAPL is assumed to be distributed uniformly across all streamtubes. Dissolution from each streamtube is assumed to follow Raoult’s law. Results are used to assess how multi-component dissolution alters the source function relative to single component dissolution, as well as assess the relative importance of hydraulic conductivity heterogeneity and multi-component dissolution on the source function. Source functions for both single and multi-component DNAPLs indicate that flushing efficiency decreases as solubility decreases. However, this effect is more pronounced for the less soluble compounds in the multi-component case due to the preferential elution of the more soluble compounds. Source functions for both single and multi-component DNAPLs also indicate that greater flux reduction is achieved through less mass removal as heterogeneity increases, however the effect is less pronounced in the multi-component case.Key words DNAPL; contaminant flux; remediation; modelling


Mass depletion–mass flux reduction relationships during pumping used to determine source zone mass of a reactive

brominated-solvent DNAPL

C. D. JOHNSTON1,2, G. B. DAVIS1,2, T. P. BASTOW1, M. D. ANNABLE3, M. G. TREFRY1,2, A. FURNESS1, Y. GESTE1, R. WOODBURY1 & S. RHODES4

1 CSIRO Land and Water, Private Bag no. 5, Wembley, Western Australia 6913, [email protected] 2 School of Earth and Environment, University of Western Australia, Nedlands, Australia3 Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, Florida 32611-6450, USA 4 Rio Tinto, 120 Collins Street, Melbourne, Victoria 3000, Australia

Abstract Mass depletion–mass flux relationships usually applied to natural groundwater flow away from a dense non-aqueous phase liquid (DNAPL) source were evaluated for pumping from the source zone itself. Three simplified dissolution models (exponential, power function and rational mass) performed well in fitting data from 285 days of pumping which removed 150 kg of dissolved organics from a multi-component, reactive brominated solvent DNAPL. There was little to choose between the models. The variance of groundwater velocities observed during a partitioning inter-well tracer test (PITT) aided model parameterisation, although the power function and rational mass models fits were not particularly sensitive to these parameters. Differing dissolution rates of the two dominant components of the DNAPL did not affect the utility of the models for the period examined. Estimates from all three models of around 250 kg for the initial mass of DNAPL were similar to the 220 kg estimated from the PITT. Key words brominated solvent; DNAPL; source zone; PITT; mass depletion; mass flux reduction; groundwater


Evaluation of multi-component NAPL source zone screening models by numerical simulation

C. BEYER1, D. SCHÄFER1, C.H. PARK2, O. KOLDITZ2 & S. BAUER1

1 Institute of Geosciences, Christian Albrechts University Kiel, Ludewig-Meyn-Str. 10, 24118 Kiel, [email protected] Department of Environmental Informatics; Helmholtz Centre for Environmental Research UFZ, Permoserstr. 15, 04318 Leipzig, Germany

Abstract Conceptually simple screening models of NAPL source zone behaviour have become a popular and useful tool for the prediction of source zone longevity and contaminant discharge at NAPL contaminated sites. Here, we evaluate two multi-component NAPL dissolution screening models against synthetic contamination scenarios, generated by detailed numerical simulations. We gradually increase the complexity of the synthetic scenarios and progressively violate the simplifying assumptions inherent in the screening models in order to assess the effects of these simplifications on the prediction of the mixed NAPL source zone lifespan and contaminant emission. Results indicate that for simple source zone configurations, one of the two screening models is able to closely predict the overall source lifespan, while the

emission of highly soluble constituents may be underestimated at early and overestimated at late times. The second screening method predicts well the emissions of highly soluble compounds but underestimates the lifespan of the source. Discrepancies increase for more complex source zone configurations in heterogeneous aquifers. Key words multi-component NAPL dissolution; source zone; screening models; numerical simulation; heterogeneity


Three-dimensional modelling and analysis of dense nonaqueous phase liquid source zone architecture in heterogeneous soil

CHIU-SHIA FEN & CHANGCHIEH TSAI Feng Chia University, Department of Environmental Engineering and Science, no. 100, Wenhwa Rd.,

Taichung, Taiwan, [email protected]

Abstract Dense nonaqueous phase liquid (DNAPL) source zone characteristics was investigated through three-dimensional (3-D) simulations of DNAPL infiltration and spreading in random soil permeability fields which were generated with the same geostatistical parameters. Results show asymmetric distribution of DNAPL saturation and high variabilities of maximum DNAPL saturation and spreading in the vertical direction. This implies that two-dimensional DNAPL mass distribution may not be representative of the characteristics of 3-D distribution for assessing mass flux/reduction of source zone dissolution.Key words dense nonaqueous phase liquid (DNAPL); DNAPL source zone; numerical modelling; geostatistics, heterogeneity


The use of dynamic contact angle measurement to assess NAPL wetting hysteresis

JOHN HENEGHAN1 & RYAN D. WILSON2

1 KrotoSchool of Earth and Environment, University of Leeds, Leeds LS2 9JT, [email protected] KrotoResearch Institute, Department of Civil and Structural Engineering, University of Sheffield, Sheffield S3 7HQ, UK

Abstract The wetting behaviour of a non-aqueous phase liquid (NAPL) is known to be one


factor in controlling its behaviour in the sub-surface, and is commonly measured as a static value on a given mineral surface. However, the mobilisation and movement of NAPL in an aquifer environment is a dynamic process, with wetting behaviour also showing dynamic behaviour. Consequently it is conjectured that static contact angles are of only limited use in assessing NAPL behaviour in contaminant source zones. To this end, dynamic wetting angles were measured on three surfaces (quartz, haematite and calcite) with a range of points of zero charge (pHpzc). Measurements of dynamic advancing and receding angles were made and estimations of wetting hysteresis were calculated.Key words NAPLs; wetting; hysteresis; contact angle


Laboratory testing of temperature increases, surfactants and co-solvents as options to enhance dissolution in a brominated-solvent source zone

G. B. DAVIS1,2, T. P. BASTOW1, C. D. JOHNSTON1,2, B. M. PATTERSON1,3, M. D. ANNABLE4, P. S. C. RAO5, Y. GESTE1, R. J. WOODBURY1 & S. RHODES6

1 CSIRO Land and Water, Private Bag no. 5, Wembley, Western Australia 6913, Australia 2 School of Earth and Environment, University of Western Australia, Western Australia 6009, Australia [email protected] 3 School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, Western Australia 6009, Australia 4 Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, Florida 32611-6450, USA 5 School of Civil Engineering & Agronomy Department, Purdue University, 550 Stadium Mall Drive, West Lafayette, Indiana 47907-2051, USA 6 Rio Tinto, 120 Collins Street, Melbourne, Victoria 3000, Australia

Abstract Enhanced dissolution from a brominated-solvent, DNAPL (dense non-aqueous phase liquid) source zone at a site in Western Australia was identified as a potentially feasible strategy to reduce the net flux in a groundwater plume exiting the site. Laboratory testing of increased temperatures, and addition of selected surfactants and co-solvents was undertaken to see which would maximise the solubilisation of the DNAPL tetrabromoethane (TBA) and yet limit enhanced DNAPL mobility (assessed by reductions in interfacial tension – IFT). Increased temperatures and addition of surfactants showed only modest increases in soluble TBA up to 5000 mg L-1, with often dramatic reductions in IFT to zero. Co-solvents increased TBA solubilisation concentrations up to 144 000 mg L-1. Ethanol was chosen for subsequent testing due to its enhanced solubilisation of TBA, up to 87 000 mg L-1 at 50% ethanol, and limited reduction in IFT (7.3 mN m-1). Ethanol also has cost, environmental and safety advantages. Key words brominated solvent; co-solvent; surfactant; temperature; ethanol; DNAPL; enhanced dissolution



A regional flux-based risk assessment approach for multiple contaminated sites on groundwater bodies

S. BROUYÈRE1, P. JAMIN1, F. DOLLÉ1, B. CHISALA1,2, PH. ORBAN1, I.-C. POPESCU3, C. HÉRIVAUX4 & A. DASSARGUES1

1 Université de Liège, Fac. Applied Sciences, Dpt ArGEnCo, Geo³-Hydrogeology & Environmental Geology and Aquapôle Research Centre, Building B52, B-4000 Sart Tilman, [email protected] University of Sheffield, Groundwater Protection and Restoration Group,Kroto Research Institute, University of Sheffield, Broad Lane, Sheffield S3 7HQ, UK3 Service publique de Wallonie, DGARNE-DGO3, Division de l'Eau, Direction des Eaux Souterraines, 15, Avenue Prince de Liège, B-5100 Jambes, Belgium4 BRGM (French Geological Survey), Water Department, 1039 rue de Pinville, 34000 Montpellier, France

Abstract In the context of the Water Framework Directive, management plans have to be set up to monitor/maintain water quality in surface and groundwater bodies in the EU. In heavily industrialised and urbanised areas, the cumulative effect of multiple contaminant sources is likely, and presents a challenge which has to be evaluated. In order to propose adequate measures, the calculated risk should be based on criteria reflecting the risk of water quality deterioration, in a cumulative manner and at the scale of the entire surface water or groundwater body. An integrated GIS- and flux-based risk assessment approach for groundwater and surface water bodies is described herein, with a regional scale indicator for evaluating the quality status of the groundwater body. It is based on the SEQ-ESO currently used in the Walloon region of Belgium which defines, for different water uses and for a detailed list of groundwater contaminants, a set of threshold values reflecting the levels of water quality and degradation with respect to each contaminant. The methodology is illustrated with its first real-scale application on a groundwater body: a contaminated alluvial aquifer which has been classified at risk of not reaching a good quality status by 2015. Key words regional risk assessment; groundwater body; groundwater quality; industrial contaminants; Water Framework Directive; multiple contaminant sources


Integrated screening level evaluation of megasite redevelopment

S. SCHÄDLER, M. MORIO & M. FINKELInstitute for Geosciences, University of Tübingen, Sigwartstr. 10, 72076 Tübingen, Germany

[email protected]

Abstract Megasite redevelopment is often hampered by complex contamination and stakeholder networks. This calls for decision support to provide integrative yet transparent evaluation of redevelopment options to stakeholders with different expertise. We describe a


new integrated method for the comparative evaluation of megasite redevelopment options. The method aims to support communication between stakeholders by visualizing consequences of adjustments and alterations in planning options at screening level. It enables an early evaluation of whether and how abandoned land may be assigned a sustainable and marketable land use. To this end, we use tailored data interpretation methods and integrate basic technical issues of soil and groundwater remediation processes, economic assessment of brownfields with a transparent market-oriented risk rebate, and the contribution of planned future land use to sustainable urban and regional development. Case study results show that this method supports the identification of: (i) sustainable and economically favourable land use options, and (ii) the most influential factors to be considered during redevelopment.Key words brownfields redevelopment; integrated assessment; decision support; valuation of contaminated land; sustainable land use; remediation cost estimation


Drinking water production close to contaminant sites: a case study from the region of Basel, Switzerland

ADRIAN AUCKENTHALER1, DOMINIK BAENNINGER1, ANNETTE AFFOLTER2, ERIC ZECHNER2 & PETER HUGGENBERGER2

1 Department of Environmental Protection and Energy, Canton Basel-Land, Rheinstrasse 29, 4410 Liestal, [email protected] Department of Environmental Sciences, Applied and Environmental Geology, University of Basel, Bernoullistrasse 32, 4056 Basel, Switzerland

Abstract Production of drinking water in urban areas is challenged by different kinds of groundwater contamination. It is especially difficult to evaluate the origin of the contamination when former waste disposal sites and other sources of pollution are present. The presented site is characterized by a complex geological setting and changes in hydraulic boundary conditions over time. In order to take the appropriate measures to understand the transport processes of the contaminants, combined and adapted investigation methods were applied. They include drilling of observation wells, the chemical analysis of solid matter and groundwater as well as the construction of a 3-D groundwater flow model. Only the combination of all these methods made it possible to understand the observed distribution of contaminants. Results suggest that the actual contamination in the aquifer is due both to remobilisation of contaminants and changing hydraulic boundary conditions affecting the flow direction of the contaminant plumes.Key words contaminated site; remobilisation; volatile organic compounds; groundwater quality, numerical modelling


Three-dimensional numerical simulation of groundwater contamination by organoarsenic compounds in Kamisu City, Japan

S. WATANABE1, N. EGUSA2, T. HIRATA2, N. YOKOYAMA3, Y. YAMAZATO4

& M. MORITA5

1 Graduate School of Wakayama University, 930 Sakaedani, Wakayama City, Wakayama 640-8510, Japan2 Wakayama University, 930 Sakaedani, Wakayama City, Wakayama 640-8510, [email protected] Kanagawa Prefecture, 1 Nihon-odori, Naka-ku, Yokohama City, Kanagawa 231-8588, Japan4 Koken Ltd., 4-7 Chiyoda-ku, Tokyo 102-8459, Japan5 Ehime University, 3-5-7 Tarumi, Matsuyama City, Ehime 790-8566, Japan

Abstract The transport processes of groundwater contamination by organoarsenic compounds was examined on a large scale in Kamisu City, Ibaraki Prefecture, Japan, using a three-dimensional numerical simulation. The results of the 3-D numerical simulation revealed that groundwater contamination had spread approx. 3 km downstream from the contaminant source and also that groundwater extraction from industrial wells located downstream of the study area had limited the spread of the groundwater contamination until the operation of some wells stopped.Key words groundwater contamination; organoarsenic compounds; diphenylarsinic acid; transport processes; numerical simulation


From conceptual to numerical modelling of a complex contaminated site in Italy using hydrogeological and hydrochemical characterization

FRANCESCA BOZZANO1, NICOLÒ COLOMBANI1, MICOL MASTROCICCO2 & MARCO PETITTA1

1 Department of Earth Sciences, University of Rome La Sapienza, P.le Aldo Moro 5, 00185 Rome, [email protected] 2 Department of Earth Sciences, University of Ferrara, Ferrara, Italy

Abstract Chemical, geological and hydrogeological investigations were conducted in a polluted site in southern Italy, with the aim of improving and validating a conceptual model of groundwater flow and contaminant transport. The collected data allowed building of a numerical model, which takes into account groundwater flow interaction with salt water intrusion by a density-dependent model. Simulation results agree with field data, showing that the salt wedge intrusion has reached the pumping wells, the dissolved contaminants are completely intercepted by a P&T system and that around 25% of exploited flow comes from losses from a surface seawater canal. Finally the three dimensional flow model was validated by new data collected in

2009, and it is now used to forecast and to manage the pumping rates of more than 70 wells.Key words conceptual model; numerical model; remediation; mega-sites; Italy


Experimental and mathematical methods to quantify the water flux and the transport processes in heterogeneous aquifer model systems

MARKO HÜNNIGER1, SUSANNE I. SCHMIDT1,2, NICOLAS PEUCKMANN1

& PIOTR MAŁOSZEWSKI1

1 Helmholtz Zentrum München–German Research Center for Environmental Health (Germany), Institute of Groundwater Ecology, Ingolstädter Landstr. 1, 85764 Neuherberg, [email protected] Centre for Systems Biology (CSB), School of Biosciences, University of Birmingham, Birmingham, UK

Abstract Suitable use of water resources requires a fundamental understanding of filter, buffer and storage functions of soil/water systems. Heterogeneous systems, which include different flow paths (e.g. karst and fissured aquifers and/or multilayered porous media) are of special importance. The aim of this investigation was to assess the heterogeneity of water fluxes and to quantify the transport processes in an aquifer system model. The experiments were performed in an indoor groundwater aquifer system model. Two artificial tracers, bromide and tritium, were simultaneously injected through a fully penetrating well, yielding a 2-D transport process. Mathematical mass transport models based on analytical and numerical methods were used, and adapted for describing heterogeneity.Key words mass transport processes; heterogeneity of water fluxes; artificial tracers


Influence of pore water and microbial heterogeneities on the evolution of NAPL contamination at old mega sites

D. PUIGSERVER1, L. CÓNSOLA1, J. M. CARMONA1, J. M. NIETO2, A. CORTÉS3 & M. GRIFOLL2

1 Departament de Geoquímica, Petrologia i Prospecció Geològica, Universitat de Barcelona, C/Martí i Franquès s/n, 08028 Barcelona, [email protected] Departament de Microbiologia. Universitat de Barcelona, C/Martí i Franquès s/n, 08028 Barcelona (Spain), Diagonal Sud, Facultat de Biologia, Edifici nou, Pl. Baixa. DIAGONAL, 645, 08028 Barcelona, Spain3 Departament de Productes Naturals, Biologia Vegetal i Edafologia. Facultat de Farmàcia, Diagonal Sud,

Facultat de Farmàcia, Pl. 4ª. Av. Joan XXIII, S/N. 08028 Barcelona, Spain

Abstract Industrial sites are periodically affected by contamination episodes. This has a large impact on the hydrochemical and biogeochemical background, affecting parameters such as sorption capacity, mass stored on the matrix and microbial diversity. In the case of aged episodes, the presence of contaminants in the matrix of the levels with lower hydraulic conductivity prolongs the remediation, owing to back diffusion, and simultaneously promotes a significant microbial diversity. The Petrochemical Complex at La Pineda (Spain) provides us with a good example in this regard. One of the contaminant episodes involves carbon tetrachloride and chloroform. Our work confirmed the existence of a complex matrix of organic compounds in the pore water and in groundwater accompanied by a considerable microbial diversity, evidenced by the DGGE in the sediment samples.Key words pore water; microbial communities; chloromethanes; back diffusion; inhibition of degradation


A screening level method to derive contaminant distributions in groundwater for early stage assessments of brownfields

MAXIMILIAN MORIO & MICHAEL FINKELCentre for Applied Geosciences (ZAG), Universität Tübingen, Sigwartstraße 10, D-72076 Tübingen, Germany

[email protected]

Abstract The complexity and scale of groundwater contamination at mega-sites requires an early identification and prioritization of focal areas and risks in order to drive further decisions concerning detailed investigation programmes and remediation measures. There is a need for the enhancement and appropriate processing of sparse amounts of groundwater contamination data, especially during the early investigation stages of mega-sites. We present a flow guided interpolation method (FGI) that has been adapted to the type, scale and information basis that are typically available at the early stages of revitalization projects at contaminated sites. Comparison of remediation cost estimations against investigation expenses show how uncertainty about required remediation measures and associated costs change during tiered brownfield revitalization projects.Key words particle tracking; interpolation; mega-site management; groundwater contamination; GIS; remediation costs; FGI


Contaminated mega-site management: the complex problem challenge

MARIO SCHIRMER1, KATHARINE N. FARRELL2, KEN LYON3 & JAMES ARMSTRONG3

1 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department Water Resources and Drinking Water, Ueberlandstr. 133, 8600 Duebendorf, [email protected] 2 Institute of Environmental Science and Technology (ICTA), Autonomous University of Barcelona, Campus de Bellaterra, Barcelona, Spain3 WorleyParsons Infrastructure and Environment, 100-4500 16th Avenue NW, T3B 0M6 Calgary, Alberta, Canada

Abstract In Europe and North America, industrial activity has led to special recognition of sites with mega-contamination (mega-sites), distinguished by the magnitude and chemical complexity of their contamination. They can become nearly intractable problems due to complex and intertwined influences of socio-economic, hydrogeological, biological and political elements. Mega-sites are, and will continue to be, part of the inherited environment in 21st century societies and their long-term management presents new challenges that we specifically address in this paper. We use lessons from the mega-site case study of Leuna, Germany, to develop new long-term strategies for situations where conventional remediation and management approaches may be untenable. These lessons highlight the risks associated with incomplete consideration of complex socio-ecological interactions that cannot easily be analysed or their influences predicted. Accordingly, we propose a broader risk management approach entailing iterative, adaptive assessments of both site based risks and environmental sustainability criteria. We then re-examine project planning approaches for potential mega-sites, proposing that they be expanded to include stakeholder involvement in the design of anticipative post-closure coping strategies. The underlying modelling challenge is to identify sufficient relevant problem factors to cover the broad scope of site characteristics without becoming ensnared in irresolvable detail. Key words mega-sites; groundwater; contamination; remediation; management; socio-ecological interactions


Persulfate treatment of gasoline-range organics

K. SRA1, N. R. THOMSON1 & J. F. BARKER2

1 University of Waterloo, Department of Civil and Environmental Engineering, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada [email protected] University of Waterloo, Department of Earth and Environmental Sciences, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada

Abstract Persulfate is a strong chemical oxidant with a higher oxidation potential on activation to the sulfate free radical and has been shown to be capable of destroying a wide range of organic compounds. The potential for persulfate to oxidize gasoline compounds was assessed in a series of bench-scale trials. The comprehensive data set assembled demonstrated that persulfate activated by peroxide or chelated-iron resulted in almost complete oxidation (>99%) of selected gasoline compounds; however, the associated reaction rate coefficients were practically similar to those observed using inactivated persulfate. Based on the results from this reactivity study, a pilot-scale field trial was conducted to understand the ability of inactivated persulfate to treat a well characterized gasoline source zone. The performance data


collected (organic compounds, sodium, sulfate, carbon dioxide, persulfate, carbon isotope, pH, and EC) indicated that the source zone strength was significantly reduced following treatment, although partial rebound was evident in the late-time data collected 140 days following treatment.Key words gasoline; chemical oxidation; persulfate; reaction kinetics; source zone rebound


Testing an autotrophic sulfate reduction reactor to treat sulfate-rich groundwaters highly contaminated by mining activities

FELIX BILEK & STEPHAN WAGNER Groundwater Research Center Dresden, Meraner Str. 10, 01217 Dresden, Germany

[email protected]

Abstract Autotrophic sulfate reduction in a technical in situ reactor is evaluated to remediate mining impacted groundwaters. Complete metal precipitation and sulfate removal below 2–4 mM is performed in three steps: (1) iron sulfide precipitation, (2) sulfate reduction, (3) excess sulfide stripping and sulfide reoxidation. High amounts of alkalinity can be transferred to the treated water. The reactor system has run stable for 3 years. It is adjustable to a wide range of raw water quality and is ready to be transferred to the field. The demand of H2 as e-donator and CO2 as pH-controlling species is dependant on the three parameters c(Fe), c(SO4) and c(Fe)/c(SO4).Key words in situ remediation technology; sulfate reduction; gas-bubble reactor


Evaluation in a continuous-flow column of different fermenting substrates for the reductive dehalogenation of trichloroethene

M. AZIZIAN1, I. MARSHALL2, S. BEHRENS3, A. SPORMANN2 & L. SEMPRINI1

1 School of Chemical, Biological, and Environmental Engineering, Oregon State University, 102 Gleeson Hall, Corvallis, Oregon 97331, USA [email protected] Departments of Civil and Environmental Engineering, and of Chemical Engineering, Stanford University, 318 Campus Drive, E250, Stanford, California 94305-5429, USA

3 Center for Applied Geosciences, Eberhard Karls University Tübingen, Sigwartstr. 10, Tübingen, Germany

Abstract A continuous-flow column study was conducted to analyse the reductive dehalogenation of trichloroethene (TCE) in aquifer material with a composition high in iron oxides. The column was bioaugmented with the Point Mugu (PM) culture, which is a mixed microbial enrichment culture capable of completely transforming TCE to ethene (ETH). Most of the metabolic reducing equivalents were channelled to sulfate, Fe(III), and Mn(IV) reduction. When equal electron-reducing equivalents were added, the most effective dehalogenation was achieved using formate as an electron donor, with 14% of the electron equivalents going towards dehalogenation reactions, compared to 6.7% for lactate and 9.6% for propionate. Lactate and propionate addition resulted in a significant increase in Geobacter, Spirochaetes, and Desulfovibrio phylotypes relative to Dehalococcides when compared to formate addition. Molecular results support chemical observations that a greater percentage of the electron donor addition was channeled to Fe(III) reduction when lactate and propionate were added compared to formate.Keywords reductive dehalogenation; column study; electron donors; chlorinated solvents


Increasing confidence in treatment performance assessment using a geostatistical approach

ZUANSI CAI & RYAN D. WILSON Department of Civil and Structural Engineering, University of Sheffield, UK

[email protected]

Abstract Mass discharge estimates using concentrations measured in multilevels are often made by assuming a uniform flow field; however uncertainty contributions from spatial concentration and flow field variability are often overlooked. We introduce a geostatistical approach to estimate mass discharge using transect data of concentration and hydraulic conductivity. The magnitude and uncertainty of mass discharge was quantified by conditional simulation. An important benefit of the approach is that the uncertainty from concentration and hydraulic conductivity has been accounted for during the mass discharge estimate. We used the approach for performance assessment of a source area TCE bioremediation experiment. The results show that the geostastical approach increased confidence in the mass discharge estimate, by providing a more accurate estimate with uncertainty interval. The mass discharge of dissolved parent and daughter-products of chlorinated solvent demonstrated that the engineered bioremediation has elevated the degradation rate of TCE. The accumulation of the daughter products cis-DCE and VC over the treatment period suggests that the enhanced degradation of cis-DCE and VC remains a major challenge for engineered bioremediation of DNAPL source areas.Key words mass discharge; contaminant source bioremediation; geostatistics; TCE, performance assessment


Toward enhanced remediation methods using chaotic advection

MICHAEL G. TREFRY1,2,3, GUY METCALFE4, DANIEL R. LESTER5, ALISON ORD3 & KLAUS REGENAUER-LIEB2,3,6

1 CSIRO Land and Water, Private Bag 5, Wembley, Western Australia 6913, [email protected] Western Australian Geothermal Centre of Excellence, 26 Dick Perry Avenue, Kensington, Western Australia 6151, Australia3 School of Earth and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia4 CSIRO Materials Science and Engineering, PO Box 56, Highett, Victoria 3190, Australia5 CSIRO Mathematics, Informatics and Statistics, Private Bag 33, South Clayton MDC, Victoria 3169, Australia6 CSIRO Earth Science and Resource Engineering, 26 Dick Perry Avenue, Kensington, Western Australia 6151, Australia

Abstract Many remediation activities in the terrestrial subsurface involve the need to recover/emplace distributions of scalar quantities (e.g. dissolved phase concentration and heat) from/in volumes of saturated porous media. These scalars can be targeted by pump-and-treat technologies, where target fluids are abstracted from the porous medium, or by amendment technologies, were specific chemicals or substrates are injected into the porous medium in order to promote beneficial transformations of water quality or mineralogy. Application examples include in situ leaching for precious metals, recovery of dissolved contaminant plumes, or harvesting of heat energy from geothermal reservoirs. While conventional pumping methods work reasonably well, costs associated with maintaining pumping schedules are high and improvements in efficiency would be welcome. In this paper we discuss how transient switching of the pressure at different wells can intimately control subsurface flow, generating a range of “programmed” flows with various beneficial characteristics. Some programs produce chaotic mixing flows which deliver rapid transport, whilst others create encapsulating flows which can confine pollutants for in situ treatment. In a simplified model of an aquifer subject to balanced injection and extraction pumping, chaotic flow topologies have been predicted theoretically and verified experimentally using Hele-Shaw cells. Mixing enhancement due to chaotic advection and kinematic confinement of aquifer volumes are key features of the chaotic dynamics. Understanding these phenomena may form the basis for new efficient technologies for groundwater remediation or amendment.Key words chaotic advection; pumping; flow; contamination; mixing; confinement


Applications and implications of direct groundwater velocity measurement at the centimetre scale

J. F. DEVLIN1, P. C. SCHILLIG1, I. BOWEN1, D. L. RUDOLPH2, N. R.

THOMSON3, G. P. TSOFLIAS1 & J. A. ROBERTS1

1 University of Kansas, Department of Geology, Lindley Hall rm 120, 1475 Jayhawk Blvd., Lawrence, Kansas 66045, USA [email protected] University of Waterloo, Department of Earth and Environmental Sciences, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada 3 University of Waterloo, Department of Civil and Environmental Engineering, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada

Abstract A recently developed probe for measuring groundwater velocity at the centimetre scale in porous media, the Point Velocity Probe (PVP), was deployed in separate projects to measure transient heterogeneity in a sandy aquifer undergoing aerobic bioremediation, as an aquifer characterization tool for the design of an in situ denitrification program, and as a tool for mapping flow in unprecedented detail around a dipole well. In the first project, local flow magnitudes varied in time by up to a factor of 3, and directions varied by over 40° in association with biological activity, which was independently confirmed. In the second project, detailed velocity measurements were made in a glacial outwash aquifer with average groundwater velocities estimated to be about 2–4 m/day. A thin zone of high water flux, with velocities in excess of 10 m/day was detected. This zone was later confirmed by a tracer test and by hydraulic conductivity determinations of core material from the site. In the third project, detailed measurements of flow, in three dimensions, immediately next to a dipole well, agreed well with model predictions in most locations. If PVPs continue to prove reliable in future research, much may be learned about small scale flow phenomena, including flow in reactive treatment zones. Key words groundwater velocity measurement; transient heterogeneity; bioremediation; dipole well; denitrification


Biosparging successfully limited fugitive VOCs while remediating residual weathered gasoline in a shallow sand aquifer

C. D. JOHNSTON1,2, R. WOODBURY1, T. P. BASTOW1 & Y. GESTE1

1 CSIRO Land and Water, Private Bag no. 5, Wembley, Western Australia 6913, [email protected] 2 School of Earth and Environment, University of Western Australia, Nedlands, Australia

Abstract A field trial of biosparging examined if an air injection scheme could be implemented that stimulated biodegradation and avoided the emission of fugitive volatile organic compounds (VOCs) from a weathered gasoline while maintaining effective remedial performance. The objective was to avoid costly off-gas collection and treatment usually required when treating highly volatile light non-aqueous phase liquid (LNAPL) in shallow aquifer systems. The trial was conducted in a sand aquifer where residual gasoline LNAPL contaminated the water table zone at a depth of only 2.5 m. The evolution and fate of the generated VOCs was intensively monitored by multi-level sampling from the vadose zone and flux hoods at the ground surface. A judicious air injection strategy was able to maintain VOC

mass flux within the biodegradative capacity of the vadose zone. This was despite VOC concentrations up to 160 000 g L-1 being generated from the LNAPL. Key words biosparging; air sparging; LNAPL; petroleum hydrocarbon; gasoline; volatile organic compounds; remediation; biodegradation; vadose zone


Assessment of chlorinated ethenes biodegradation in an anaerobic aquifer by isotope analysis and microcosm studies

KARIN EBERT, CHRISTINE LASKOV, SEBASTIAN BEHRENS & STEFAN HADERLEINCenter for Applied Geoscience (ZAG), Eberhard Karls University of Tuebingen, Sigwartstr. 10, 72076 Tuebingen, Germany [email protected]

Abstract This work focused on identification and quantification of natural attenuation of chlorinated ethenes in a contaminated aquifer beneath an industrial area using compound specific isotope analysis (CSIA). Presence of cis-1,2-dichloroethene (cis-DCE) and vinylchloride (VC), as well as in situ redox conditions indicated degradation of the primary contaminant trichloroethene (TCE) by reductive dechlorination. The potential for VC degradation was further corroborated by PCR-analysis on water samples which confirmed the presence of Dehalococcoides strains and VC reductases. In situ biodegradation was estimated by various approaches, including concentration measurements along the groundwater flow path, microcosm studies and by compound specific stable carbon isotope analysis. Using the Rayleigh model carbon isotope enrichment factors, ε, were determined both in the field and in microcosm experiments for each dechlorination step. Estimates of biodegradation based on enrichment factors derived from microcosms (–8.6‰ (cis-DCE) and –27.2‰ (VC)) were consistently lower (up to 40%) than those based on field data. Our results of the isotope study at field scale, microcosm experiments and molecular marker analysis provided conclusive information on natural attenuation processes and can be recommended as a general approach for site characterisation and risk assessment in NA studies. Key words natural attenuation; chlorinated ethenes; CSIA; microcosm experiments; carbon isotope fractionation


Chlorine isotope fractionation of organic contaminants: added value for in situ assessment of natural attenuation processes

CHRISTOPH AEPPLI, CHARLINE WIEGERT, HENRY HOLMSTRAND & ÖRJAN GUSTAFSSON

Department for Applied Environmental Science (ITM), Stockholm University, 106 91 Stockholm, [email protected]

Abstract A simple and accurate analytical method was developed for compound-specific determination of chlorine isotopic composition (δ37Cl) of organochlorines based on GC/MS analysis. This method was applied to investigate natural attenuation of pollutants at contaminated field sites. Chlorine isotope fractionation of chlorinated ethenes in a contaminated aquifer with mixed redox conditions was indicative for ongoing reductive dechlorination. Furthermore, the 37Cl enrichment associated with biotransformation of polychlorinated phenols, which are prevalent soil and groundwater contaminants, was investigated in laboratory and field studies. Overall, our results demonstrate the potential of δ37Cl compound-specific isotope analysis for assessing the fate of organochlorine groundwater and soil contaminants. Key words organochlorines; chlorine isotope fractionation; compound-specific stable isotope analysis; natural attenuation; biodegradation


Monitored natural attenuation of arsenic: promises and pitfalls from two case studies

JANET G. HERINGEawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600

Dübendorf, [email protected]

Abstract Monitored natural attenuation (MNA) relies on processes, such as sorption and precipitation that sequester arsenic (As) in the subsurface and thus protect downgradient receptors. It is not a simple exercise to determine whether MNA could be a viable strategy for managing As-contaminated groundwater at a specific site. On the basis of two previously-described case studies, the type of evidence that could support selection of MNA as a management option is summarized. The potential for MNA to be effective is discussed in the context of the mechanisms by which As is mobilized in the source area and sequestered away from the source area. Particular attention is paid to the assumption that persistence of As in the source area is evidence of biogeochemical control of mobilization. The situations where MNA is most likely to be effective are suggested.Key words biogeochemistry; mobilization; redox; sequestration; sorption


Influence of natural attenuation and river fluctuations on

benzene dispersion in an alluvial aquifer subject to strong interactions with surface water

J. BATLLE-AGUILAR1,2, S. BROUYÈRE1, A. DASSARGUES1, B. MORASCH3,4

& D. HUNKELER3

1 Department ArGEnCo, Hydrogelogy Unit and Aquapôle, University of Liège, Building B52/3, B-4000 Sart Tilman, [email protected] Present address: National Centre for Groundwater Research and Training (NCGRT), School of the Environment, Flinders University, GPO Box 2100, Adelaide, SA-5001, Australia3 Centre for Hydrogeology, University of Neuchâtel, Rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland4 Present address: Institute for Geosciences, Center for Applied Geosciences (ZAG), Sigwartstr 10, D-72076 Tübingen, Deutschland

Abstract A numerical groundwater flow and transport model, calibrated under transient conditions, was used to simulate benzene attenuation in an alluvial aquifer discharging into the Meuse River, Belgium. The mean benzene degradation rate used in the model was quantified in situ along the groundwater flow path using compound-specific carbon isotope analysis (CSIA). The results of the transient solute transport simulations confirmed that benzene concentrations decreased almost five orders of magnitude within 70 m downgradient of the main source zone, and dropped below the detection limit in the zone adjacent to the river. This was consistent with the absence of benzene in downgradient piezometers located in the vicinity of the river. Interestingly, benzene concentrations were observed to be inversely correlated to river water levels, leading to the hypothesis that benzene dispersion was controlled by natural attenuation and river fluctuations.Key words groundwater; brownfield; benzene; stable isotope fractionation; natural attenuation


Proving natural attenuation at a petroleum hydrocarbon contaminated site by high-resolution direct push measurements as a basis for reactive transport modelling

ANITA PETER1, BENEDICT MILES2 & GEORG TEUTSCH3

1 Christian-Albrechts-University of Kiel, Institute for Geosciences, Ludewig-Meyn-Str. 10, 24118 Kiel, [email protected] GCI – Groundwater Consulting Engineers GmbH, Bahnhofstr. 19, 15711 Königs Wusterhausen, Germany3 Helmholtz Centre for Environmental Research - UFZ GmbH, Permoser Str. 15, 04318 Leipzig, Germany

Abstract At a former military air-field site contaminated by kerosene as NAPL phase, comprehensive site investigations were performed in order to prove the efficacy of natural attenuation. The site investigations included high-resolution direct-push measurements to determine lithological and geochemical parameters, as well as contaminant data. A three-

dimensional flow model based on the site data indicated that a perched aquifer extending over a portion of the site has a strong influence on the distribution of groundwater recharge to the main aquifer by intercepting and focusing it in localised areas. On the basis of the three-dimensional flow model a multi-component reactive transport model was set up to simulate transport of four major contaminants as well as of four electron acceptors along two vertical transects in the groundwater flow direction. Model predictions show that the presence of the perched aquifer has a major impact on the contaminant plume development due to strongly reduced groundwater recharge rates, and thus reduced supplies of oxygen and sulphate. Furthermore, the limited supply of Fe(III) in the mineral phase as an immobile electron acceptor eventually leads, after its depletion, to a renewed growth of the contaminant plume.Key words natural attenuation; direct-push technology; reactive multi-component transport modelling


Three-dimensional analytical models for isotope ratios in pollutant plumes of organic contaminants undergoing different biodegradation kinetics

PATRICK HÖHENER1 & OLIVIER ATTEIA2

1 Laboratoire Chimie Provence, UMR 6264, Universités d'Aix Marseille I, II et III-CNRS, Case 29, 3, Place Victor Hugo, F-13331 Marseille Cedex 3, France

[email protected]

2 Université de Bordeaux, EGID, 1 Allée Daguin, 33607 Pessac Cedex, France

Abstract We present analytical models that are able to predict stable isotope ratios and contours of concentrations for organic pollutants in homogeneous aquifers for three different assumptions regarding the biodegradation kinetics. Stable isotope ratios are computed after modelling the individual reactive transport of isotopic species in the aquifer. The isotopes in these species undergo fractionation by biodegradation or sorption. We find that the isotope ratios in the plumes are very sensitive to the assumptions underlying the biodegradation kinetics in the models. When biodegradation occurs throughout the core of the plume as a first-order reaction, the transversal gradients in isotope ratios are smooth. When biodegradation is modelled by double-Monod kinetics in a bi-molecular reaction with an electron acceptor at the plume fringes, steep transversal isotope gradients are observed. Combined plume-and-fringe degradation produces the most realistic predictions of isotope ratios. Isotope fractionation by sorption causes another pattern of isotope ratios, where isotope shifts are restricted to near the forerunning front of the expanding plume. Key words risk assessment; groundwater plumes; organic pollutants; monitoring; stable isotopes


Design and evaluation of bench-scale tank experiments for the quantification of transverse dispersion using numerical simulations

E. BALLARINI1, S. BAUER1, C. EBERHARDT2, M. ROLLE2, P. GRATHWOHL2 & C. BEYER1

1 Institute for Geosciences, University of Kiel, Ludewig-Meyn-Str. 10, D-24118 Kiel, [email protected] Center for Applied Geosciences, University of Tübingen, Sigwartstraße 10, D-72076 Tübingen, Germany

Abstract 2-D bench-scale tracer tank experiments were performed in a well controlled laboratory set-up in order to reproduce the behaviour of contaminants in groundwater. Transverse dispersion, which represents an important parameter for mixing processes, was determined so far by employing a “forward method”, using the analytical solution of the 2-D advection–dispersion equation for a constant concentration line source. The correctness of this method is evaluated in this work using a “backward method”. Synthetic tank experiments, where all the parameters (porosity, hydraulic conductivity, longitudinal and transverse dispersivity, etc.) are known a priori, were run, the numerical results re-elaborated and the fitted parameters compared to the respective “true” values used in the numerical simulations. The synthetic experiments demonstrate that for a porous medium with a grain size of 0.5–0.75 mm and a porosity of 0.37, the fitted longitudinal and transverse dispersivities are 5.4 10-4 m and 4.2 10-5 m, respectively. A sensitivity analysis showed which parameters affect the plume distribution and where in the tank the influence is higher and easier to measure. Moreover, the numerical model can be used to improve the set-up for new tank experiments. The parameter estimation procedure developed for the conservative tracer tests will also be applied to the upcoming reactive transport experiments.Key words tank experiments; numerical modelling; dispersivity; tracer plume; inverse modelling


Two-dimensional flow-through experiments: versatile test systems for a combined investigation of transport and reactive processes in porous media

M. ROLLE1, G. CHIOGNA1, C. EBERHARDT1, C. HABERER1, C. GRIEBLER2, O. A. CIRPKA1 & P. GRATHWOHL1

1 Center for Applied Geoscience, University of Tübingen, Sigwartstrasse 10, D-72076 Tübingen, [email protected] 2 Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, D-85764 Neuherberg, Germany

Abstract In the present study we report on the results of laboratory experiments aimed at

mailto:[email protected]%0D

investigating transport and diffusion/dispersion limited reactions in saturated porous media. In similar 2-D bench-scale set-ups we studied different processes, including transport of conservative tracers, fast abiotic mixing-controlled acid/base reactions, and contaminant biodegradation, including aerobic degradation and oxidation of petroleum hydrocarbons (i.e. toluene and ethylbenzene) coupled to nitrate reduction. The experiments were carried out in both homogeneous and heterogeneous porous media under steady-state and transient (i.e. oscillating) flow fields. The scale of the experimental set-up allowed high-resolution monitoring by combining a number of physico-chemical and microbiological methods. The laboratory experiments were always accompanied by numerical flow and transport simulations. We compared the modelling results with the observed data and we used different measures, including a newly defined flux-related dilution index, to quantify the mixing and the reaction extent under various experimental conditions. Key words natural attenuation; laboratory experiments; mixing; biodegradation; numerical modelling


Boundary conditions for explosives degradation in a Quaternary aquifer

A. WEBER & S. TRÄNCKNERDGFZ e.V., Dresden Groundwater Research Centre, Meraner Str. 10, 01217 Dresden, Germany

[email protected]

Abstract Decades after contamination explosives and related compounds (ERC) still persist in aquifers. A factorial design of laboratory studies was applied to discriminate limiting factors on the degradation of polar and less polar ERC. The results were confirmed by evaluation of groundwater observations at a field site in Elsnig (Germany). Especially the persistence against microbial attack, lack of carbon sources and complexity of contamination hinder degradation of ERC. The present work increases insight into the still sparse understanding of the influence of geochemical aquifer conditions on natural attenuation processes for ERC.Key words nitroaromatic compounds; hexogen; trinitrotoluene; natural attenuation; limited degradation; groundwater; redox


Groundwater pollution potential of additives used in borehole heat exchanger fluids

D. ILIEVA, B. MORASCH & S. B. HADERLEINCenter for Applied Geoscience (ZAG), Environmental Mineralogy & Chemistry, Eberhard-Karls Universität

Tübingen, Sigwartr. 10, D-72076 Tübingen, [email protected]

Abstract Ground-based heat exchanger systems need to be evaluated in terms of potential effects on groundwater quality due to the risk of leakage of borehole heat exchanger fluids. They contain glycols or inorganic brines as major components, but typically also various additives. As the identity of these additives is proprietary information, the major objective of this study was to obtain an overview of the identities and properties of individual additive compounds used in borehole heat exchanger fluids. Leading companies in the production and distribution of these fluids were invited to participate in a confidential data survey. A wide variety of additive compounds were assembled, which can be grouped into ten chemical classes: triazoles, carboxylic acids/carbonates, phosphonates, alcohols, aldehydes, ethers borates, silicates, nitrates and hydroxides. Among these substances some are also used in other applications, e.g. aircraft de-icing fluids and engine antifreeze formulations, and are of potential concern for groundwater quality. Based on their abundance in the investigated borehole heat exchangers and their concerning environmental behaviour in the subsurface, benzotriazoles, tolyltriazoles and some carbonates were selected for further biodegradation experiments.Key words additives; benzotriazoles; groundwater pollution; antifreeze formulations; biodegradability; geothermal energy


MNA site investigations – comparison of conceptual approaches derived from virtual model scenarios and real site studies

S. GRANDEL, D. SCHÄFER, S. BAUER, A. DAHMKE & C. BEYERChristian-Albrechts-University Kiel, Institute for Geosciences, Ludewig-Meyn-Str. 10, 24118 Kiel, Germany

[email protected]

Abstract Site investigation approaches for assessment of natural attenuation processes have been derived from synthetic model scenarios and were compared to real site investigation procedures. Comparison was focused on methods used for site investigation. Direct-push technologies and isotope measurements have growing importance in practice compared to methods used 10 years ago; and have also been increasingly applied in non-research projects. Key words monitored natural attenuation; site investigation concepts; field and model studies


Assessing of the effect of physical heterogeneity on single well

tracer tests using imaging experiments

G. L. BARNS, R. D. WILSON & S. F. THORNTON Groundwater Protection and Restoration Group, University of Sheffield, Kroto Research Institute, Broad Lane, Sheffield S3 7HQ, [email protected]

Abstract Single well forced gradient tracer tests can be used to assess aquifer properties for natural attenuation and remediation design. Measurements of aquifer properties monitored in the well are depth-averaged and therefore may misrepresent or fail to identify important flow and mass flux paths. Such spatial information is critical for remedial system design. UV imaging tests were undertaken in a pseudo 2-D tank filled with glass beads, with a centrally positioned slotted well screen. Fluorescent tracer migration during dipole flow tracer tests (DFTTs) and push–pull tests (PPTs) were examined under isotropic and simple layered conditions. Results show that small variations in hydraulic conductivity significantly affect tracer flow. For DFTTs these produce discernable differences in breakthrough curves, which can be used to help identify important hydrogeological features.Key words imaging; heterogeneity; tracer tests; natural attenuation; remediation


Scaling kinetics of organic compounds degradation: laboratory values extended to field sites

O. ATTEIA & A. MANGERET Institut EGID, 1 allée Daguin, 33607 Pessac Cedex, France [email protected]

Abstract In this paper we study the degradation kinetics of chlorinated solvents in the laboratory and in the field. Microcosms were prepared from groundwater from a field site and showed biodegradation of PCE to ethene only when organic matter (as propionate) was added to the microcosm. In the field, the same geochemical model was applied in conjunction with a transport model to simulate chlorinated solvents and electron acceptors concentrations. Due to the uncertainty on the size of the degradation zone (reducing area) several values of kinetic constant and several models might be used to fit the measured field data. A model using kinetic values obtained in the laboratory suggests that degradation only occurs in a small area. From this study and data from other sites, two major conclusions can be drawn: (i) at most sites the area where degradation occurs seems to be fairly small, and (ii) for chlorinated solvents plume modelling, working on electron acceptors spatial distribution is as important as assessing the kinetic degradation rates.Key words natural attenuation; modelling; chlorinated solvents; kinetics



Enhanced natural attenuation – determining the potential for reductive dechlorination in an oxic aquifer

DANIEL BUCHNER1, MEENAKSHI LOGANATHAN1, SEBASTIAN BEHRENS1, CHRISTINE LASKOV1, THOMAS SCHÖNDORF2 & STEFAN HADERLEIN1 Center for Applied Geoscience (ZAG), Eberhard Karls University of Tuebingen, Sigwartstr. 10, 72076 Tuebingen, [email protected] 2 HPC HARRESS PICKEL CONSULT AG, Ziegelhofstraße 210a, 79110 Freiburg i. Br., Germany

Abstract The aim of the study was to demonstrate the stimulation of reductive dehalogenation of chlorinated ethenes in an oxic aquifer. Microcosms with aquifer material were amended with different organic substrates as electron donors in order to stimulate microbial reductive dechlorination. Next to molasses and lactate a commercial product was applied, which has been described as controlled-release carbon zero valent iron particles (EHC™). In addition, vitamins and bicarbonate buffer were added to the microcosms to further stimulate growth of halorespiring microorganisms. Reductive dechlorination was followed by measuring chlorinated ethene concentrations and their stable carbon isotope fractionation. The microbiological community was monitored by terminal restriction fragment length polymorphism (T-RFLP). The EHC™ amended microcosms showed only incomplete conversion of PCE, resulting in an accumulation of cis-DCE after incubation for 103 days. In the microcosms amended with molasses, complete reductive dechlorination of PCE to ethene was observed within 56 days. The degradation of the less chlorinated ethenes correlated with the appearance of Dehalococcoides microorganisms and carbon isotope fractionation. Also one of the parallel set-ups amended with lactate showed complete dechlorination. In this microcosm an isotopic overtaking of VC was observed, proving complete microbiological degradation to ethene. Control microcosms without substrate addition showed no dechlorination during the whole experiment. Our study demonstrates that the potential for microbial reductive dechlorination was present and can be stimulated in an oxic aquifer by establishing reducing conditions and supplementing fermentable substrates.Key words enhanced natural attenuation; chlorinated ethenes; isotope fractionation; T-RFLP; oxic aquifer


Determination of in situ biodegradation rates using 13C-labelled aniline

BARBARA MORASCH1,2, PATRICK HÖHENER3 & DANIEL HUNKELER1

1 Centre of Hydrogeology and Geothermics, University of Neuchâtel, Rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland 2 Present address: Centre of Applied Geoscience (ZAG), University of Tübingen, Sigwartstr. 10, D-72076 Tübingen, Germany

[email protected] Laboratoire Chimie Provence, Université de Provence-CNRS, Place Victor Hugo, F-13331 Marseille Cedex 3, France

Abstract A concept was developed that allowed the quantification of contaminant biodegradation in complex systems employing 13C-labelled compounds. Sediment–groundwater microcosms with contaminated aquifer material were spiked with 13C-labelled mono-aromatic model substrates and their fate was studied over time. First-order biodegradation rate constants were generated from the apparent concentration decrease in the water phase, where HgCl2-amended controls accounted for abiotic contaminant loss. Secondly, rate constants were calculated from the increase of 13C-CO2 in the headspace of the microcosms upon substrate utilization. The model compound aniline proved that both 13C-based approaches were suitable to demonstrate the intrinsic mineralization potential. Moreover, rate constants based on the 13C recovery in the CO2 of the headspace were unaffected by sorption compared to rate constants derived from concentration measurements in the water phase. Key words 13C-stable isotopes; groundwater contamination; biodegradation rates; mono-aromatic compounds


Compound specific C and N isotope analysis of negatively charged pesticides: on-injector derivatization/GC-IRMS versus LC-IRMS

SANDRA REINNICKE, ANAT BERNSTEIN & MARTIN ELSNERInstitute of Groundwater Ecology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, [email protected]

Abstract We developed analytic methods to enable Compound Specific Isotope Analysis (CSIA) of two frequently detected pesticides, bentazone and MCPA. Both occur in negatively charged form at circum neutral pH and are not easily analysed by GC/IRMS. We therefore pursued two strategies, (i) derivatization by trimethylsulfonium hydroxide (TMSH), followed by GC-IRMS, and (ii) analysis by liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). In the tested concentration range (4000–5000 ppm), accurate and precise 15N values of –0.63‰ ± 0.3‰ (n = 33) were observed for the bentazone derivative when TMSH was used in a small excess. This value was in perfect agreement with results from elemental analyser-IRMS (EA-IRMS) (15N = –0.62‰ ± 0.03‰). In contrast, carbon isotope values 13C of methylated bentazone and MCPA showed a bias towards negative values becoming more positive with increasing excess of TMSH. With an excess of 250 or more, constant and reproducible 13C values (SD < 0.3‰) were obtained for bentazone concentrations between 3 and 300 ppm and a MCPA concentration of 200 ppm. In both cases values showed an offset of 1‰ compared to EA-IRMS values, likely because of the addition of a carbon atom during derivatization. In comparison, LC-IRMS results for 13C of bentazone (60–200 ppm) also resulted in reproducible values, but surprisingly also showed an offset of 1‰ compared to EA-IRMS values. Our study


showed that both methods (derivatization with GC-IRMS and LC-IRMS) are feasible approaches for isotope analysis of ionic pesticides, allowing a novel way to assess their fate in the environment.Key words compound specific isotope analysis; GC-IRMS; LC-IRMS; derivatization


Natural attenuation of gasoline hydrocarbons from residual sources containing ethanol

JULIANA G. FREITAS1, MARIAN T. MOCANU1, JOSÉ LUIZ G. ZOBY1, JOHN W. MOLSON2 & JAMES F. BARKER1

1 University of Waterloo, Department of Earth and Environmental Sciences, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada [email protected] Université Laval, Dept. of Geology and Geological Engineering, Quebec City, Quebec G1V 0A6, Canada

Abstract Natural attenuation limits the length of dissolved plumes emanating from gasoline contaminated sites and is commonly applied as a remediation technique. As ethanol is often used as a gasoline additive, it can potentially impact the biodegradation of aromatic hydrocarbons from gasoline. Three gasoline residual sources with different ethanol fractions were placed in a pristine aquifer to evaluate the impact of ethanol in gasoline on hydrocarbon biodegradation. Numerical modelling was applied to compare dissolved plumes formed from each source. Biodegradation was found to be adequately represented by Monod-type kinetics, with oxygen being the main limiting factor. The greater overlap between the ethanol and hydrocarbon plumes in the high (95%) ethanol fraction caused a significant reduction in hydrocarbon biodegradation.Key words ethanol; gasoline; natural attenuation; numerical modelling


Application of groundwater life expectancy in the delineation of time-dependent capture zones for water supply wells

J. W. MOLSON1 & E. O. FRIND2

1 Université Laval, Dept. of Geology & Geological Engineering, Québec, Québec G1V 0A6, Canada [email protected] University of Waterloo, Dept. of Earth & Environmental Sciences, Waterloo, Ontario N2L 3G1, Canada

Abstract Mean groundwater age and mean life expectancy are useful concepts for describing steady-state groundwater systems. Mean life expectancy is related to capture probability, which expresses the probability of a particle being captured by a well, taking into account uncertainty in the form of dispersion and mixing. We show that mean life expectancy can be used in the delineation of time-dependent well capture zones, which are required for defining wellhead protection areas. The life expectancy approach is an alternative to particle tracking, which neglects uncertainty. Key words mean groundwater age; mean life expectancy; capture probability; well capture zones; groundwater protection


Geometry of well capture zones in fractured media: uncertainties using an equivalent porous media approach

MARTÍ BAYER-RAICH1, JERKER JARSJÖ2 & SALVADOR JORDANA1

1 Amphos 21, Passeig de Garcia i Faria, 49–51, 08019 Barcelona, [email protected] 2 Dept. of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, Sweden

Abstract We aim to set up a methodology to establish a range of validity of the radial flow approach for fractured aquifers using a 2-D scenario with two families of fractures. At first, the parameters considered will be the size (radius) of the capture zone (rcylinder) in an equivalent homogeneous aquifer and the ratio of the hydraulic conductivity of fractures and rock matrix (Kfract/Krock). We take as a master variable the maximum distance dmax from the pumping well to the isochrone. Results based in one realization show that, if the capture zone is sufficiently large, the fractured aquifer can be treated as a homogeneous porous media considering equivalent properties. Our preliminary simulations indicate that the cylinder formula rcylinder can be applied to fractured aquifers providing reasonable (i.e. order of magnitude) estimates of dmax

for the range of Kfract/Krock<20 studied here.Key words well capture zone; fractured media; equivalent porous media; radial flow; cylinder formula


Risk analysis for riverine groundwater extraction

R. M. PAGE1, P. HUGGENBERGER1, J. EPTING1 & G. LISCHEID2

1 Department of Environmental Sciences, Applied and Environmental Geology, University of Basel, Bernoullistr. 32, 4056 Basel, [email protected]

2 Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Hydrology, Eberswalder

Str. 84, 15374 Müncheberg, Germany

Abstract Natural filtration in aquifers can improve the quality of groundwater relative to infiltrating surface water. During high discharge events, the microbial load of the groundwater can be several orders of magnitude higher than under normal flow conditions. The risk of contamination of groundwater extraction wells through infiltrating river water has been assessed by: (1) considering hydraulic gradients between the river and the groundwater, as well as the behaviour of quality parameters, such as turbidity, electrical conductivity and spectral absorbance coefficient; (2) principal component analysis to identify areas, time periods and parameters sensitive to infiltrating river. The results illustrate the major processes influencing the groundwater body in the study area, thus enabling a real-time assessment of potential sources of contamination.Key words river–groundwater interaction; principal component analysis; drinking water


Using probabilistic well vulnerability criteria for a risk-based preventive drinking water safety concept

RAINER ENZENHOEFER, WOLFGANG NOWAK & RAINER HELMIG University of Stuttgart, Institute for Hydraulic Engineering, Department for Hydromechanics and Modeling of Hydrosystems, Pfaffenwaldring 61, 70569 Stuttgart, Germany [email protected]

Abstract The most common concept to control the risk of drinking water contamination is the delineation of advection-based well-head protection zones. In 2006 Frind et al. extended this concept by introducing four intrinsic well vulnerability criteria that account for additional advective–dispersive transport information, such as dilution of peak concentrations through diffusion and dispersion. Our approach quantifies the uncertainty of well catchments and protection zones based on these advective–dispersive vulnerability criteria within a probabilistic framework. In order to account for uncertainty and to keep computational costs low at the same time, we combine Monte Carlo simulations with a temporal moment approach for model reduction. Our method allows stakeholders to take informed risk-based decisions in order to better control and manage the risk within their well catchments, which is necessary to develop complete risk management schemes as recommended by current Water Safety Plans.Key words well catchment delineation; wellhead protection; well vulnerability; uncertainty; risk assessment


Nationwide characterisation of buffering capacities and


background compositions of groundwater aquifers in the Netherlands

JASPER GRIFFIOEN1,2, JANNEKE KLEIN1,2 & RUTH HEERDINK2

1 TNO Geological Survey of the Netherlands, PO Box 80.015, 3508 TA Utrecht, The [email protected] Deltares, PO Box 85467, 3508 AL Utrecht, The Netherlands

Abstract Sustainable groundwater management asks for good insight into the geochemical characteristics of the groundwater aquifers. A nationwide environmental geochemical characterisation of shallow sedimentary deposits was initiated in the Netherlands to meet this information need. The methodology is briefly outlined and some results are presented for the northern part of the Netherlands.Key words geochemistry; characterisation; aquifer sediment; buffering capacity; background composition


Capture probability maps for addressing uncertainty: protection vs mitigation

MARCELO R. SOUSA, EMIL O. FRIND & DAVID L. RUDOLPH University of Waterloo, Department of Earth and Environmental Sciences, 200 University Avenue West, N2L 3G1 Waterloo, Ontario, [email protected]

Abstract Decision-makers often rely on numerical groundwater models to support source water protection decisions for areas surrounding water production wells. However, model results can be associated with a high degree of uncertainty. One way to address this uncertainty is to consider an array of alternative scenarios deemed representative of the system. A simple method is proposed to combine the results from alternative scenarios into two types of capture probability maps: one focused on protection, and the other on mitigation. The proposed approach is applied to a municipal well located in a complex glacial aquifer system in Ontario, Canada. For this case, the two types of maps are found to differ substantially.Key words uncertainty; numerical modelling; source water protection; capture zones


Assessing the impact of PrefaceBeneficial Management Practices for controlling nitrate concentrations in well water

R. RAHMAN1, E. O. FRIND2 & D. L. RUDOLPH2 1 Schlumberger Water Services (Canada) Ltd., 460 Philip Street, Suite 101, Waterloo, Ontario N2L 5J2, Canada 2 Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada [email protected]

Abstract Beneficial Management Practices (BMPs) can be used to control nitrate concentrations in wells in agricultural areas. For optimal benefit, it is necessary to identify the best areas for BMP application, to determine the actual impact, and to estimate the time frame of the impact. The concept of well vulnerability can be used for this purpose. An example focused on a municipal well located in a complex moraine aquifer system is provided. A backward vulnerability analysis is used to map optimum areas as well as response time for BMP application, while a forward analysis is used to plot the evolution of the response under various scenarios. The impact is given in terms of the change in concentration in the well water and the time frame for the change to take effect, all relative to a no-BMP scenario. Because all values are relative, denitrification need not be taken into account. Key words Beneficial Management Practices; impact assessment; nitrate concentration; well vulnerability; well capture zone; groundwater modelling


Leaching of trace elements from a clay till aquitard by seepage from an oil sands tailings facility

A. A. HOLDEN1, S. E. HAQUE, R. B. DONAHUE3 & A. C. ULRICH1

1 3-133 Markin/CNRL Natural Resources Engineering Facility, University of Alberta, Edmonton T6G 2W2, [email protected] Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver V6T 1Z4, Canada3 Applied Geochemical Engineering Solutions Inc. 9535-91 Street, Edmonton T6C 3P6, Canada

Abstract In northern Alberta, Canada, large oil sands tailings containment structures are being constructed on top of buried glaciofluvial sand channels. These channels have the capacity to act as potential migration pathways, facilitating the seepage of tailings water out of the containment structure and into adjacent water systems. Preliminary hydrogeological modelling of the first known site suggests that process-affected (PA) water from the tailings pond will infiltrate through the clay till and into the underlying sand channel. However, the environmental consequences of long-term seepage are not known. In the present study, radial diffusion cells have been constructed to examine the mitigation or mobilization of trace elements as ingressing PA water interacts with the native clay till sediments/pore waters, en route to the underlying aquifer. The data show no evidence of release of As, Se, Cr or Cd resulting from the introduction of PA water to the clay till sediment-pore water systems. Results suggest the mitigation or uptake of Mo and Zn, and the release of Si, Pb, Sr and Ba

across each of the three aquitard zones tested. Understanding the environmental impact of tailings seepage is of great importance given the increasing scarcity of water resources in Alberta. The present research offers a scientific basis to guide future remediation and reclamation strategies, environmental impact assessments, and seepage mitigation schemes. Key words trace elements; seepage; process-affected water; oil sands tailings ponds–geochemical interactions; clay till


Modelling nitrate dynamics in the well catchment Baltenswil (Zurich, Switzerland)

FRITZ STAUFFER & SEBASTIAN STOLLETH Zurich, Institute of Environmental Engineering, Wolfgang-Pauli-Strasse 15, 8093 Zurich, Switzerland

[email protected]

Abstract Nitrate dynamics are investigated for the catchment of the drinking water pumping well Baltenswil (Zurich, Switzerland). Land use in the well catchment is mainly agriculture and forestry. Nitrate input into the subsurface is estimated based on yearly maps of crop rotation on the agricultural plots within the catchment, and on the results from lysimeter studies on nitrate mobilization for similar soils and climatic conditions and crop rotation. Calibration of the saturated part of the flow model is performed using long-term series of head data in wells and piezometers. Transient flow and transport modelling was performed using the software MIKE SHE for the period between 1994 and 2009 and compared with measured head and nitrate data. The results point to the importance of nitrate input and groundwater recharge rate for the complex nitrate transport system.

Key words groundwater; nitrate; drinking water well; solute transport; modelling


Application of an agronomic model to determine optimal management strategies to reduce nitrate concentrations in groundwater

S. PEÑA-HARO1,2, M. PULIDO-VELAZQUEZ2, H. YANG3, J. LIU4 & C. LLOPIS-ALBERT2

1 Institute of Environmental Engineering, ETH Zurich, HIL G33.3, Wolfgang-Paulistrasse 15, CH-8093 Zürich, [email protected] Department of Hydraulics and Environmental Engineering, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022, Valencia, Spain3 Eawag, Swiss Federal Institute of Aquatic Science and Technology, PO Box 611, 8600 Dübendorf, Switzerland4 School of Nature Conservation, Beijing Forestry University, Beijing Haidian District 100083, Beijing, China

Abstract Nitrate is among the most common and widespread pollutants in groundwater, while agricultural activities are often the main source. Water pollution has given rise to the development of an extensive legal framework that sets groundwater maximum concentrations as policy targets. In order to design cost-efficient policies to control the nitrate emissions, it is necessary to link agronomic models that show the effects of loading rates on crop yield and nitrate leaching, with numerical groundwater flow and transport models that simulate the resulting groundwater nitrate concentration due to temporal and spatial variations in fertilizer applications. Agronomic models help to define functions that can relate crop yield, on-ground nitrogen fertilization, nitrate leaching to groundwater, and nitrogen stock in the soil. In this paper, the GEPIC model is tested to estimate nitrogen leaching and crop yield functions for crops at the study area of the Salobral-Los Llanos aquifer, within the western Mancha (Albacete province, Spain). These functions can then be embedded in an integrated hydro-economic framework that allows simulation of the effectiveness of different land use and fertilizer use policies.Key words GEPIC; nitrate groundwater pollution; groundwater management; hydro-economic modelling; crop yield; nitrogen leaching


A method for standardising groundwater nitrate concentrations

A. VRIJHOEF & L. J. M. BOUMANSRIVM, National Institute for Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The

[email protected]

Abstract As part of the EU Nitrates Directive, leaching is monitored on farms in the Netherlands. The upper metre of groundwater, thought to best represent leaching of a previous year, is sampled yearly and analysed for nitrate. The resulting nitrate concentrations are related to farm management. This relationship is complicated by annual variations in groundwater recharge causing variations in dilution. A soil simulation model is used to quantify the variations in groundwater recharge due to annual changes in precipitation surplus. With meteorological data on evaporation and precipitation, the concentration of a hypothetical tracer in the upper metre of groundwater is modelled. The tracer concentrations are used to reduce variation in nitrate concentrations caused by the effect of changes in groundwater recharge.

The resulting nitrate concentrations can be better related to farm management, especially nitrogen surplus.Key words groundwater quality; groundwater recharge; nitrate; modelling; monitoring


Guidelines for optimal design of electron acceptor injection wells to enhance bioremediation of contaminated groundwater

MOHAMED M. A. MOHAMEDDepartment of Civil and Environmental Engineering, United Arab Emirates University, PO Box 17555, Al Ain, United Arab [email protected]

Abstract The finite element model METABIOTRANS, which simulates the fate and transport of contaminants in the subsurface, is used to identify general guidelines for the optimal design of electron acceptor injection wells to enhance bioremediation of contaminated groundwater aquifers. Several scenarios were simulated to examine the sensitivity of remediation effectiveness to the number and locations of wells and injection rates of electron acceptors. Results show that an injection well placed near the plume core, where highest contaminant concentrations exist, is always desired. The nearest injection well to the source zone caused higher stimulation to bacterial growth than further downgradient injection wells. It also exhibited longer resident time for the electron acceptors in the aquifer; and therefore yielded higher biodegraded contaminant mass. Higher injection rates of electron acceptors are not always needed to increase bioremediation efficiency. This should be noticed in real practices of groundwater remediation design.Key words groundwater; bioremediation; electron acceptors; modelling


Fate of iodinated X-ray contrast media compounds under aerobic and anaerobic groundwater conditions

B. M. PATTERSON1,2, M. SHACKLETON1, A. J. FURNESS1 & F. BUSETTI3

1 CSIRO Land and Water, Private Bag no. 5, Wembley, Western Australia 6913, [email protected] 2 School of Biomedical, Biomolecular and Chemical Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia3 Curtin Water Quality Research Centre (CWQRC), Department of Applied Chemistry, Curtin University, GPO


Box U1987 Perth, Western Australia 6845, Australia

Abstract Iodinated X-ray contrast media (ICM) compounds have been detected in the effluent of wastewater treatment plants (WWTP) in Perth, Western Australia, as well as in other locations around the world. With the increased use of treated wastewater for managed aquifer recharge (MAR), potential groundwater contamination from these compounds has become a concern, and there is little data available on the fate of these compounds under different aquifer geochemical conditions. The fate of two ICM compounds, iohexol (IOX) and iodipamide (IDP) were investigated under both aerobic and anaerobic aquifer conditions during 12-month large-scale column experiments. Under natural aerobic conditions, IOX was observed to biodegrade with a half life of <1 day. However, IDP was persistent throughout the experiment (half life >100 days). Under natural anaerobic conditions, no degradation of IOX was observed (half life >100 days), while IDP degraded rapidly with a half life of 2 days. Based on this data, a sequential remediation strategy was investigated that involved establishing an anaerobic reductive zone half way along a 200 cm-long aerobic column to provide a 100 cm-long aerobic zone followed by a 100 cm-long anaerobic zone. Results from this experiment confirmed that a sequential natural aerobic/enhanced anaerobic remediation strategy was viable, with rapid IOX degradation (half life <1 day) in the aerobic zone, followed by rapid IDP degradation (half life <1 day), along with denitrification and sulphate reduction, in the anaerobic zone of the column. Key words X-ray contrast media; iohexol; iodipamide; biodegradation; groundwater; managed aquifer recharge


Vulnerability zones to nitrate pollution in an Alpine region (South Tyrol, Italy)

ROBERTA BOTTARIN1, UTA SCHIRPKE1 & ULRIKE TAPPEINER1,2

1 EURAC – European Academy of Bolzano, Institute for Alpine Environment, Viale Druso 1, 39100 Bolzano, Italy [email protected] University of Innsbruck, Institute of Ecology, Sternwartestr. 15, 6020 Innsbruck, Austria

Abstract The individuality of vulnerability zones to nitrate pollution of surface water and groundwater is of fundamental significance for an improved land use policy. A first study to identify areas vulnerable to nitrate pollution of agricultural origin was performed in South Tyrol. The survey intended to focus its attention on the relationship between agriculture and nitrogen concentrations in surface water and groundwater for the whole provincial territory. Representative parameters contributing to determining contamination status were taken into account: potential nitrogen pollutant loads of agricultural as well as zootechnical origin, environmental factors, e.g. distribution of precipitation, and also territorial factors, e.g. slope of the used agricultural surface. Combining the parameters it was possible to calculate a potential vulnerability for each municipality.Key words agriculturally derived nitrates; vulnerable zones; water pollution; preliminary recognition survey; Central Alps


Nitrogen leaching to groundwater and surface water in the Dutch peat region

A. E. J. HOOIJBOER & B. FRATERSRIVM – National Institute for Public Health and the Environment, PO Box 13720, BA Bilthoven, The

[email protected]

Abstract Since 1995 the National Institute for Public Health and the Environment (RIVM) has engaged in monitoring the groundwater quality at farms in the Dutch peat region. This monitoring programme aims to assess the effect of the Dutch Minerals Policy on the water quality. Measurements in the peat region show that total-nitrogen concentrations have remained fairly stable. The decrease in nitrogen surplus on farms is not yet reflected in the water quality on farms. This might be explained by variable weather conditions and variable decomposition of peat. In the peat region nitrogen is leached mainly towards ditches. Surface drains play a significant role in this process.Key words nitrogen leaching; peat region; minerals policy; farmland; The Netherlands


Multivariate statistical approach to a hydrogeochemical characterization of the Virttaankangas aquifer, SW Finland

PÄIVI NIEMISTÖ1 & KIRSTI KORKKA-NIEMI2

1 University of Turku, Department of Geology, FI-20014 University of Turku, [email protected] University of Helsinki, Department of Geology, FI-00014 University of Helsinki, Finland

Abstract To reveal hydrochemical processes controlling water chemistry in the large Quaternary Virttaankangas sedimentary aquifer two multivariate statistical methods, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to classify groundwater samples collected from 50 monitoring wells. The PCA results showed three main factors: (a) “calcite dissolution factor”, (b) “anthropogenic factor”, and (c) “silicate weathering factor”. HCA was applied to PCA factor scores to delineate the spatial variability of hydrogeochemical data. HCA revealed six geochemically distinct clusters. Samples from clusters 1 and 2 show abnormality in water chemistry, whereas samples from clusters 3–6 show a division pattern related to hydrogeological units and flow paths. Inverse geochemical modelling with PHREEQC indicates that calcite dissolution is the most important reaction controlling water chemistry in fine-grained and coarse-grained units, whereas silicate weathering reactions are responsible for hydrochemical characteristics in the areas of littoral sand and perched groundwater.


Key words groundwater quality; hierarchical cluster analysis; principal component analysis hydrogeochemistry; modelling; Finland


Modern groundwater management: measures undertaken at the source – pilot project nitrate reduction in Klettgau SH

KURT SEILER1, IWAN STÖSSEL1, ROGER BIEDERMANN1 & MARKUS BOLLER2

1 Interkantonales Labor, Mühlentalstrasse 184, Postfach, CH-8201 Schaffhausen, [email protected] Urban Water Management, Eawag, Überlandstrasse 133, PO Box 611, CH-8600 Dübendorf, Switzerland

Abstract Nitrogen loss of soils into groundwater bodies is a common threat to drinking water resources in areas of high agricultural activities. Here we present a case study from the northern part of Switzerland, where a series of soil cultivation measures were applied in order to remediate one specific groundwater well. The water of this well could no longer be used due to elevated nitrate concentrations. The impact of the project on nitrate concentration in the well was predicted by a series of groundwater model simulations. Continuing monitoring both of groundwater quality and of soil layers by suction lysimeters allowed continual improvement and control of the success of the measures. After four years, the water from the well can again be used as drinking water. The observed gradient of nitrogen decrease in the groundwater can now be used to refine the groundwater models.Key words contamination; modelling; qualitative groundwater protection; nitrogen; agriculture


Groundwater quality in Dutch water management

HILDE F. PASSIER1, RUTH HEERDINK1, JOACHIM ROZEMEIJER1, 2, ATE VISSER1, YAN-CHUN ZHANG1, 2, STEFAN JANSEN1 & VICTOR BEUMER1

1 Deltares Research Institute, Subsurface and Groundwater, Princetonlaan 6, PO Box 85467, 3508 AL Utrecht, The [email protected] Utrecht University, Faculty of Geosciences, The Netherlands

Abstract Good groundwater quality is essential for numerous receptors in the Netherlands, such as drinking water supply, aquatic and terrestrial ecology, and water supply for agriculture and industry. In the meantime, the anthropogenic use of the water system affects the groundwater quality. We are challenged to use our water resources in a sustainable way. This


paper elaborates on a number of examples of our projects on groundwater quality for Dutch water management.Key words water management; groundwater quality; surface water quality; age dating; purification; nitrate pollution; natural attenuation; groundwater depending ecosystems


The role of permeability distribution on nitrate fate and transport, in different scale experiments under saturated conditions

M. MASTROCICCO1, N. COLOMBANI1,2 & G. CASTALDELLI3

1 University of Ferrara, Department of Earth Sciences, Via Saragat 1, Ferrara, [email protected] 7 University ”La Sapienza” of Rome, Department of Earth Sciences, Piazzale A. Moro 5, Rome, Italy 3 University of Ferrara, Department of Biology and Evolution, Via L. Borsari 46, Ferrara, Italy

Abstract A range of laboratory and field experiments has been performed to quantify NO3– clean

up times in sandy loamy sediments representative of the Po Plain lowlands (northern Italy), an intensively cultivated area affected by serious nitrate pollution for decades. Column and tank experiments were performed to elucidate the relevant transport and redox processes affecting nitrogen dissolved species, in order to study the same processes in controlled 1-D and 3-D environments. In addition, a grid of piezometers were installed and monitored in a former agricultural field, to quantify the presence and degradation of nitrogen dissolved species in the shallow unconfined aquifer. NO3

- was found to be persistent in column, tank and field experiments, due to limited availability of organic substrates needed for denitrification processes. The comparison between laboratory transport experiments and the field site monitoring highlighted the role of permeability distribution in defining clean up times, with silt and clay lenses that hamper groundwater flux and provide a continuous source of nitrogen via diffusion. This study confirms that laboratory experiments can give a good representation of the redox processes undergone by nitrogen species in saturated conditions, but despite of this, laboratory experiments should not only account for 1-D flow and transport processes, but also for 3-D flow field.Key words nitrate; degradation; persistence; soil; sediments; groundwater


Application of multivariate analytical methods in assessment of factors responsible for waterborne Kashin-Beck disease in Sichuan, China

XINXIN GUO, YIQUN GAN & YANXIN WANG School of Environmental Studies and MOE Key Laboratory of Biogeology and Environmental Geology, China

University of Geosciences, Wuhan 430074, [email protected]

Abstract This study investigates the relationship between water chemistry and Kashin-Beck disease (KBD) within the Ruo’ergai County of Sichuan Province using multivariate statistical techniques. A total of 38 groundwater and surface water samples were collected in 2008. The data sets obtained were processed using Principal Component Analysis (PCA) and Factor Analysis (FA). The results indicate four factors for major constituents in groundwater that accounted for 91.2% of the variance in the data set. In surface water, five factors accounted for 89.9% of the total variance. Regression analysis of the KBD prevalence and factor scores reflect the relationship between the factors and the Kashin-Beck disease. Combined with the geological and hydrological evidence, it can be concluded that the major reasons for the occurrence of Kashin-Beck disease in the study area are the relatively low concentrations of F, P, Mn, and Se in drinking water. These low concentrations are greatly related to the acid and reduced environment caused by the organic matter.Key words groundwater/surface water quality; multivariate analytical method; Kashin-Beck disease; Sichuan, China


Risk-based prioritisation of point sources through assessment of the impact on a water supply

NIELS D. OVERHEU1, MADS TROLDBORG2, NINA TUXEN1, JOHN FLYVBJERG3, HENRIK ØSTERGAARD3, CARSTEN B. JENSEN3, PHILIP J. BINNING2 & POUL L. BJERG2

1 Orbicon A/S, Ringstedvej 20, 4000 Roskilde, Denmark2 Dept. of Environmental Engineering, Technical University of Denmark, Miljoevej B113, 2800 Kgs. Lyngby, [email protected] 3 Capital Region of Denmark, Kongens Vænge 2, 3400 Hillerød, Denmark

Abstract A large number of point sources threaten groundwater resources. A tool is presented which enables a uniform and transparent risk assessment and prioritisation of these point sources at the catchment scale with respect to the needs of further investigation or remediation. The tool integrates aquifer vulnerability mapping, site-specific mass flux estimates on a local scale from all the sources, and 3-D catchment-scale fate and transport modelling. It handles sources at various knowledge levels and accounts for uncertainties. The tool estimates the impacts on the water supply in the catchment and provides an overall prioritisation of the sites using a flexible scoring system. The tool is tested on two catchments in Denmark and the results are discussed.Key words risk assessment; prioritisation; point sources; groundwater; modelling; catchment scale



Decision analysis to minimize agricultural groundwater demand and salt water intrusion using treated wastewater

AHMED AL-JUAIDI1, UNGTAE KIM2 & JAGATH J. KALUARACHCHI3

1 Utah Water Research Laboratory, Utah State University, Logan, Utah 84322-8200, [email protected] 2 Institute for a Secure and Sustainable Environment, University of Tennessee, Knoxville, Tennessee 37996, USA3 College of Engineering, Utah State University, Logan, Utah 84322-4100, USA

Abstract The Gaza Coastal aquifer with rapidly increasing population and limited land is experiencing multiple threats to groundwater from salt water intrusion and pollution from agricultural contaminants. The Gaza Strip of Palestine is a classic example with limited freshwater supply due to the rapid depletion of water levels, and increasing seawater intrusion and water demands. In such regions, use of treated wastewater (TWW) is a viable option if public health issues are addressed. The purpose of this paper is to address the beneficial use of TWW in agriculture while considering net benefit, economic efficiency of water use, and public health risks. A health risk assessment applied to the Gaza Strip suggests that increasing the elapsed time between irrigation and consumption and switching to different irrigation systems are practical measures to reduce public health risks. The decision analyses show that the proper allocation of freshwater and TWW and distribution of land area by crop type can significantly increase net benefit and economic efficiency of water use. Net benefits increased between 46% and 65%, fresh groundwater use reduced between 30% and 43% while increasing the economic efficiency of water use by three-fold compared to the existing conditions. When groundwater abstraction reduced from 57 to 36 million m3/year, the area with hydraulic head below mean sea level can be decreased by 58%, indicating significant aquifer recovery. Key words public health; seawater intrusion; net benefit; decision analysis; treated wastewater


Passive samplers for monitoring VOC in groundwater: prospects related to mass flux measurements

G. VERREYDT1,2, J. BRONDERS1, I. VAN KEER1, L. DIELS1 & P. VANDERAUWERA2

1 VITO, Environmental Modeling Unit – Land and Water Management, Boeretang 200, 2400 Mol, [email protected] Artesis University College of Antwerp – Department of Industrial Sciences, Paardenmarkt 92, 2000 Antwerpen, Belgium

Abstract The potential use of passive samplers for the direct measurement of groundwater related VOC mass fluxes is examined. A review of current passive samplers for the measurement of organic contaminants in water yielded the selection of 18 samplers which were screened for a number of criteria. These criteria are related to the possible application of the sampler for the measurement of VOC mass fluxes in groundwater. This screening study indicates that direct measurement of VOC mass fluxes in groundwater is possible with very few passive samplers. Currently the Passive Flux Meter (PFM) is the only passive sampler which has proven to effectively measure mass fluxes in near-source groundwater. A passive sampler for mass flux measurement in plume zones with regards to long-term monitoring still needs to be developed or optimized. This would be of considerable value in the development of risk-based assessment and management of soil and groundwater pollutions. Key words groundwater; passive samplers; mass fluxes; VOCs


Do variable hydrologic and redox conditions influence organic pollutants in the streambed?

C. SCHMIDT & E. KALBUSHelmholtz Centre for Environmental Research – UFZ, Department of Hydrogeology, Permoserstraβe 15,

04318 Leipzig, [email protected]

Abstract Significant natural attenuation of organic pollutants may occur in streambed sediments because of the transition from anaerobic to aerobic conditions and an increased microbial activity. Alternating directions and magnitudes of water flow in the streambed may enhance or inhibit the supply of oxygen to the streambed and thus influence the redox zonation. In a field study at a small stream, we observed the variability of hydraulic gradients, streambed temperatures, redox conditions and monochlorobenzene (MCB) concentrations in the streambed over the course of five months. During the observation period the hydrologic conditions changed from losing to gaining. Redox conditions were highly variable in the shallow streambed at a depth of 0.1 m below the streambed surface. At depths of 0.3 m and 0.5 m, the redox conditions were stable and comparable to those typically found in the aquifer. The concentrations of MCB in the streambed were not systematically influenced by varying hydrologic or redox conditions. Key words streambed; temperature; streambed contamination


Assessing groundwater travel times and biogeochemical processes during riverbank filtration under the aspect of


river restoration

T. VOGT1, P. SCHNEIDER1, S. PETER1,2, E. DURISCH-KAISER1,2, M. SCHIRMER1 & O. A. CIRPKA3

1 Eawag – Swiss Federal Institute of Aquatic Science and Technology, Department Water Resources and Drinking Water, Überlandstrasse 133, 8600 Dübendorf, [email protected] ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, Universitätsstr. 8, 8092 Zürich, Switzerland3 University of Tübingen, Center for Applied Geoscience, Sigwartstr. 10, 72076 Tübingen, Germany

Abstract The largest Swiss groundwater reservoirs are located in gravel aquifers of flood plains with channelized rivers. Although the number of river restoration projects is increasing, the effects of river restoration on riverbank filtration and groundwater quality are still under debate. For detailed research on biogeochemical processes during river water infiltration, field data of nutrients or pollutants and advective groundwater travel times to observation and production wells are crucial parameters. We present results of a study on bank filtration at a field site in northeast Switzerland, which is located at a channelized and restored section of the peri-alpine losing River Thur. We analyse time series of electrical conductivity in the river and riparian groundwater wells to quantify mean residence times by means of non-parametric deconvolution and relate the calculated travel times with biogeochemical processes occurring during riverbank filtration.

Key words riverbank filtration; electrical conductivity; time series analysis; non-parametric deconvolution; biogeochemistry


Experimental investigation of evaporation and condensation in sandy soils under simulated arid conditions

E. SHIMOJIMA1, I. TAMAGAWA2 & J. V. TURNER3

1 Daido University, 40 Hakusui-cho, Minami-ku, Nagoya 457-8532 Japan

[email protected] River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193 Japan

3 CSIRO Land and Water, PO Wembley 6913, Western Australia, Australia

Abstract The diurnal cyclic process of evaporation and condensation in bare soils in arid and semi-arid areas was explored experimentally in laboratory sand columns under controlled meteorological conditions of periodic step-wise variation of humidity and solar radiation to simulate daytime and night-time conditions. The materials used were a dune sand and a silica

sand; for the former an initially dry condition was set and for the latter a fixed water table with NaCl solution at high concentration was set. During the experiments measurements of water vapour density in pore volumes and column weights were used to determine the behaviour of the evaporation–condensation front in the drying stage (daytime) and wetting stage (night-time). Vapour movement caused by phase changes and development of solute accumulation in the sand column are discussed.Key words arid area; evaporation-condensation; sand column experiment; simulated periodically varying atmospheric condition; salinisation


Effect of an artificial flood wave on groundwater in the hyporheic zone

STEFAN BANZHAF1, TRAUGOTT SCHEYTT1, REINHARD BIERL2 & ANDREAS KREIN3

1 Technische Universität Berlin, Department of Applied Geosciences,Hydrogeology Research Group, Ackerstrasse 76, 13355 Berlin, [email protected] Trier University, Department of Hydrology, 54286 Trier, Germany3 CRP – Gabriel Lippmann, Department of Environment and Agro-Biotechnologies (EVA), Rue du Brill 41, 4422 Belvaux, Luxembourg

Abstract Hyporheic zone processes arising from varying hydraulic boundary conditions, e.g. flood waves in surface water, are frequently characterized as transient. However, their effects are often difficult to assess. In this study, the effects of a single artificial flood wave on the interaction between groundwater and surface water in the hyporheic zone was examined by measuring the responses of hydraulic head, temperature and chemical constituents in a stream and its riverbank. The analyses of the field experiment show a significant positive correlation between the artificial flood wave and the hydraulic heads in the groundwater. The transport of water from the stream to groundwater has not yet been clearly proven. The results show, however, that even short term and local changes in hydraulic conditions can impose an effect on the local groundwater quantity, whereas wave induced transport of compounds could not be verified under the given constraints.Key words groundwater; surface water; interaction; hyporheic zone; flood wave


Spatial characterization of hydraulic conductivity in alluvial gravel-and-sand aquifers: a comparison of methods

S. DIEM, T. VOGT & E. HOEHNEAWAG, the Swiss Federal Institute of Aquatic Science and Technology, Department Water Resources and Drinking Water, Ueberlandstrasse 133, 8600 Duebendorf, [email protected]

Abstract For groundwater transport modelling on a scale of 10–100 m, detailed information about the spatial distribution of hydraulic conductivity is of great importance. At a test site (10 × 20 m) in the alluvial gravel-and-sand aquifer of the perialpine Thur valley (Switzerland), four different methods were applied on different scales. The comparison of the results showed that multilevel slug tests give the most reliable results at the required scale. For their analysis, a plausible value of the anisotropy ratio (Kvertical/Khorizontal) is needed. For alpine and perialpine aquifers, a range of 0.1–0.2 can be expected. Flowmeter logs are recommended, if the relative distribution of hydraulic conductivity is of primary importance. Sieve analyses should be used, if an accuracy of a factor of 3 is acceptable. Pumping test results indicate the upper boundary of the natural spectrum of hydraulic conductivity at the scale of the test site.Key words hydraulic conductivity; multilevel slug tests; flowmeter logs; sieve analyses; pumping test


Field study and iron reactive simulation in riverbank water supply well fields

EKATERINA KAZAK, SERGEY POZDNIAKOV & NATALIA MUROMECLomonosov Moscow State University (MSU) – Faculty of Geology, Department of Hydrogeology, Leninskiye

Gory, 119899, Moscow, Russian [email protected]

Abstract The quality of groundwater pumped out by riverbank water supply well fields often tends to decrease due to infiltration of water from surface reservoirs. A similar situation is the case for an investigated reservoir located in the central Russian Federation. Water intakes are located at the bank of a river whose level has been raised by >3 m since the construction of a water reservoir in this river. Numerical flow simulation shows that 70–90% of groundwater is replenished by water from the reservoir. Monitoring of the groundwater quality shows that iron concentration is higher than the maximum admissible value for drinking water. We have been involved in the project aimed at identifying and locating sources of iron in groundwater coming from the intakes. At the initial stage a series of field experiments was performed, such as chemical tests of groundwater, reservoir and near-bottom water, as well as sampling of aquifer rock and bottom sediments. Eventually, the most probable source was found – high content of iron minerals in bottom of the reservoir. The process of dissolution of iron minerals due to reservoir water infiltration through bottom sediments into the aquifer was simulated by PHREEQC-based numerical model.Key words groundwater quality; riverbank filtration; iron; PHREEQC; river–groundwater interaction


Hydrogeochemical and isotopic indications of groundwater-surface water interactions at Lake Pyhäjärvi, SW Finland

KIRSTI KORKKA-NIEMI1, ANNE RAUTIO1, PÄIVI NIEMISTÖ2 & JUHA A. KARHU1

1 Department of Geosciences and Geography, University of Helsinki, PO Box 64, 00014 Helsinki, [email protected] Department of Geology, University of Turku, 20014 Turku, Finland

Abstract General water chemistry, PCE/TCE-concentrations and 18O isotopic compositions are used to indicate the groundwater discharge from esker aquifers into Lake Pyhäjärvi and to evaluate the proportion of groundwater in inshore water. Discharge sites were identified via measuring temperature, electrical conductivity (EC), and pH in the lake water; and measuring lake bed sediment temperatures. There are differences in EC and pH, and the main ionic as well as 18O isotopic composition of surface and groundwater. The proportion of groundwater in inshore water ranged from 6 to 34% near the shoreline. PCE and TCE concentrations confirmed the discharge into the lake in a contaminated part of one aquifer.Key words hydrogeochemistry; groundwater; surface water; 18O-isotopes; PCE/TCE


Monitoring of change of the chemical composition of groundwater during vegetation periods

INOM NORMATOV, MUSLIMA KHOLMIRZOEVA &NABI NOSIROV Institute of Water Problems, Hydropower and Ecology, Academy of Sciences, Republic of Tajikistan, 12

Parvin Street, Dushanbe 734002, [email protected]

Abstract The results of research on the change of a chemical compound in groundwater, depending on the time of year and quantity of precipitation, are presented. The essential influences of the irrigation of the lands in vegetation periods on quality of groundwater are observed. Also, the results of monitoring the condition of irrigated lands of cotton sown regions in Tajikistan on the level and degree of groundwater mineralization are presented.Key words contamination; chloride; nitrate; vegetation; agriculture; impact



Denitrification hot spot and hot moments in a restored riparian system

SIMONE PETER1,2, ROMANA RECHSTEINER1,2, MORITZ F. LEHMANN4, KLEMENT TOCKNER5, TOBIAS VOGT3, BERNHARD WEHRLI1,2 & EDITH DURISCH-KAISER1,2

1 Eawag, CH-6047 Kastanienbaum, Switzerland [email protected] Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, CH-8092 Zurich, Switzerland3 Eawag, CH-8600 Dübendorf, Switzerland 4 Inst. of Environmental Geosciences, University of Basel, CH-4056 Basel, Switzerland5 IGB, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, DE-12587 Berlin, Germany

Abstract Water samples were collected along hydrological connectivity in different functional process zones (FPZs) (sensu Thorp et al., 2006) of a restored riparian zone of the River Thur, Switzerland. Denitrification was determined by the stable N and O isotope ratios of nitrate (NO3

-) and the abundance of functional denitrification genes, and related to organic carbon (OC) concentrations and discharge. The results showed that substantial losses of NO 3

- and an enrichment of 15N and 18O in the residual NO3

- pool occurred post-flooding in a FPZ where the abundance of denitrification genes was increased and the vegetation cover was dominated by willow, a pioneer plant exhibiting high below-ground C-dynamics. During flooding, dissolution of plant-derived OC occurred and fuelled post-flood denitrification activity in the groundwater. Thus, the interplay of FPZ configuration, subsurface hydrology, and flow regime of the river help direct the formation of denitrification hot spots and moments in a restored riparian system.Key words biogeochemical hot spot/moment; denitrification; river restoration


Identifying biogeochemical processes beneath stormwater infiltration ponds in support of a new best management practice for groundwater protection

ANDREW M. O’REILLY1, NI-BIN CHANG2, MARTIN P. WANIELISTA3 & ZHEMIN XUAN2

1 US Geological Survey, Florida Water Science Center, 12703 Research Pkwy, Orlando, Florida 32826, [email protected] University of Central Florida, Department of Civil, Environmental, and Construction Engineering, 4000 Central Florida Blvd, Building 91, Suite 442, Orlando, Florida 32816, USA3 University of Central Florida, Water Research Center and Stormwater Management Academy, 4000 Central Florida Blvd, Building 91, Suite 442, Orlando, Florida 32816, USA

Abstract When applying a stormwater infiltration pond best management practice (BMP) for protecting the quality of underlying groundwater, a common constituent of concern is nitrate .

Two stormwater infiltration ponds, the SO and HT ponds, in central Florida, USA, were monitored. A temporal succession of biogeochemical processes was identified beneath the SO pond, including oxygen reduction, denitrification, manganese and iron reduction, and methanogenesis. In contrast, aerobic conditions persisted beneath the HT pond, resulting in nitrate leaching into groundwater. Biogeochemical differences are likely related to soil textural and hydraulic properties that control surface/subsurface oxygen exchange. A new infiltration BMP was developed and a full-scale application was implemented for the HT pond. Preliminary results indicate reductions in nitrate concentration exceeding 50% in soil water and shallow groundwater beneath the HT pond.Key words biogeochemistry; natural attenuation; groundwater protection; stormwater infiltration; best management practice


Reactive transport upscaling of small reactive heterogeneities for regional modelling

DAVID RODRÍGUEZ AGUILERA1,2, JOHAN R. VALSTAR1 & JASPER GRIFFIOEN1

1 Deltares / TNO, Geological Survey of The Netherlands, Princetonlaan 6, 3508 TA Utrecht, The [email protected] Utrecht University, Department of Earth Sciences – Geochemistry, Budapestlaan 4, 3584 CD Utrecht, The Netherlands

Abstract Sedimentary deposits often contain small heterogeneities in the form of intercalated lenses. These elements can affect both the transport of species and the biogeochemical reactions that the transported species undergo. The particular geometry of these frequently clayey lenses, extremely thin in comparison with the large lateral dimensions, would require very fine gridded models in order to accurately model the transport and reaction processes taking place. Therefore, the simulations would require a very large computational effort. On top, an exhaustive description of the sedimentary deposits would be necessary to accurately describe the physicochemical properties of these porous media. We develop a practical approach to infer the global effect of the small lens-shaped heterogeneities for the transport and reaction of species without having to model these features in detail. In particular, our goal is to characterize the effect of the small heterogeneities on reactive transport at a regional scale. We develop an upscale algorithm to reproduce the breakthrough curves of a model with local small scale heterogeneities by using an equivalent homogenous model, hereby relating the upscaling mechanism with the statistical properties of the field.Key words groundwater; modelling; heterogeneity; reactivity upscaling; regional reactive transport model


Use of chemical and biological techniques in the remediation of sites contaminated by chlorinated solvents

D. PUIGSERVER1, J. M. CARMONA1, J. BARKER2, A. CORTÉS3, X. NOGUERAS1 & M. VILADEVALL1

1 Dept. de Geoquímica, Petrologia i Prospecció Geológica. Facultat de Geologia, Universitat de Barcelona, C/Martí i Franquès, s/n. E-08028 Barcelona, [email protected] Earth Sciences Department. Faculty of Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada3 Dept. de Productes Naturals, Biologia Vegetal i Edafologia. Facultat de Farmàcia, Universitat de Barcelona. Av. Joan XXIII, s/n. E-08028 Barcelona, Spain

Abstract Natural attenuation of chloroethenes can be inhibited by microbial competition, which hinders biodegradation of these contaminants by adversely affecting the strategies of remediation. The studied area is affected by a punctual PCE contaminant episode and by diffuse nitrate contamination. Biogeochemical and multi-isotopic characterization reveals a marked variation in the rates of chloroethene degradation as a function of simultaneous reactions, i.e. reduction of sulphates and nitrates, and reductive dechlorination of chloroethenes. This variability makes the exclusive use of bioremediation techniques difficult. However, the combined use of in situ chemical and biological techniques proves to be successful in the laboratory. Different experiments on aerobic and anaerobic microcosms reveal high rates of biotic and abiotic degradation as well as an increase in the isotopic fractioning.Key words biodegradation; chloroethenes; isotopic fractioning; ISCO; ISCR


Modelling hydrologic and geochemical filtering of reactive solute transport in catchments

P. S. C. RAO1, N. B. BASU2, S. ZANARADO1,3, C. J. HARMAN4, M. SIVAPALAN4 & A. RINALDO5

1 School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907-2051, [email protected] 2 Department of Civil & Environmental Engineering, University of Iowa, Iowa City, Iowa 52242-1527, USA 3 Università degli Studi di Padova, Padova, Italy4 Department of Geography, University of Illinois Urbana-Champagne, Urbana, Illinois 61801-3671, USA5 Laboratory of Ecohydrology, Ecole Polytechnique Federale de Lausanne, CH-1015, Lausanne, Switzerland

Abstract We explored how anthropogenic and hydro-climatic forcing controls the dynamics of water and pesticide transport through hillslopes, as reflected in the hydrologic and water-quality measurements in stream networks draining intensively managed agricultural catchments. We adopted two parsimonious modelling approaches to examine the stochastic,


episodic transport through hillslopes in response to a series of rainfall events. In both approaches, the hillslopes and the stream network act as a series of nonlinear, hierarchical, dynamic filters, to both delay and attenuate the hydrologic and biogeochemical signals observed in catchments. We used the two modelling approaches to explore the specific coupling of the hydrological and biogeochemical processes, and the role of the antecedent conditions in the observed emergent patterns along the river networks.Key words catchment-scale contaminant export; mass-response function; piston displacement model; stochastic modelling; pesticide fate and transport


Comparison of gasoline spills with different ethanol fractions

JULIANA G. FREITAS, JOHN D. MOSQUERA, ANTHONY L. ENDRES & JAMES F. BARKER

University of Waterloo, Department of Earth and Environmental Sciences, 200 University Avenue West, Waterloo, Ontario N2L 3G1, [email protected]

Abstract The impacts of ethanol in gasoline on the behaviour of organic compounds in the subsurface are likely to be dependent on the volume fraction of ethanol present in the mixture. To evaluate how spills of gasoline containing 10% ethanol and 95% ethanol differ, two controlled releases were performed on a field scale. Soil cores and GPR surveys were conducted to evaluate the behaviour at the source zone and groundwater concentrations were monitored downgradient of the source zone. The source zone configuration in the two releases had different shapes, with the E95 source being more equally distributed. The cross section of the gasoline hydrocarbon dissolved plumes were also different depending on the fraction of ethanol in the mixture released. The hydrologic conditions following the release were also found to interfere with the downgradient concentrations.Key words ethanol; gasoline; unsaturated zone; field-scale


Reactive transport column experiment in volcanic ash soil and numerical modelling with anion and cation exchange reactions

K. NAKAGAWA1, S.-I. WADA2 & K. MOMII3

1 Kagoshima University, Department of Environmental Sciences and Technology, 1-21-24 Korimoto, Kagoshima 890-0065, Japan

kei-naka @ agri.kagoshima-u.ac.jp 8 Kyushu University, Department of Plant Resources, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan 3 Kagoshima University, Department of Environmental Sciences and Technology, 1-21-24 Korimoto, Kagoshima 890-0065, Japan

Abstract Groundwater contamination by nitrate from agricultural fields is a problem shared by many parts of the world. Kagoshima prefecture, Japan, is an important agricultural district experiencing this problem. In this study, laboratory column experiments were performed and a numerical model was developed to improve understanding of nitrate transport process through volcanic ash soils overlying the aquifer in this region. The volcanic ash soil (Kuroboku) was packed into the column that was assembled by stacking rings of an equal height. A solution of different salts, representing a soil solution after fertilizer application was added from the top of the column by constant head boundary conditions. The inflow was stopped when the dispersion front reached about the middle depth. Cation and anion concentrations in the solid and the liquid phases were analysed by ion chromatography. Competitive sorption due to cation and anion exchange was observed. Concentrations of anion components in liquid phase exceeded the initial concentration of the mixed solution due to desorption from the solid phase. Transport processes in the column experiments were analysed with the aid of reactive transport simulations incorporating cation and anion exchange reactions. Vertical profiles of the Kuroboku-experiment were reproduced by the developed model. Our model qualitatively reproduced the anion concentration exceedence due to desorption, anion retardation and cation exchange.Key words laboratory column experiment; reactive transport model; volcanic ash soil; ion exchange; nitrate pollution


Laboratory experiments to determine oxygen transport in a fluctuating capillary fringe

C. M. HABERER & P. GRATHWOHLEberhard-Karls University Tuebingen, Institute for Geoscience, Centre for Applied Geoscience, Sigwartstrasse 10, D-72076 Tuebingen, [email protected]

Abstract Quasi 2-D bench-scale flow-through experiments were conducted to investigate the effect of entrapped air on oxygen transport across the capillary fringe during changing water table levels. We applied a non-invasive fibre-optical sensor technique to measure vertical oxygen concentration profiles in the transition zone between the saturated and the unsaturated zone at high spatial resolution. The characteristics of the oxygen profiles were related to mass flux measurements at the outlet of the flow-through chamber. The results show that transverse vertical dispersion and equilibrium partitioning between the gas and the aqueous phase are sufficient to explain vertical transfer of oxygen into groundwater. Key words flow-through experiments; capillary fringe; mass transfer; oxygen; water table fluctuations; entrapped air


Estimation of nitrate discharge in a fractured limestone aquifer below a dairy farm in Ireland

FLORIAN LANDIG1, OWEN FENTON2, PAUL BONS1, DEIRDRE HENNESSY3, KARL RICHARDS2 & PHILIPP BLUM1,4

1 University of Tübingen, Institute for Geoscience (IfG), Sigwartstraße 10, 72076 Tübingen, [email protected] Teagasc, Johnstown Castle, Environmental Research Centre, Wexford, Ireland3 Teagasc, Moorepark Dairy Production Research Centre, Fermoy, Co. Cork, Ireland4 Karlsruhe Institute of Technology (KIT), Institute for Applied Geosciences (AGW), Kaiserstraße 12, 76131 Karlsruhe, Germany

Abstract Intensification of agriculture in areas with underlying fractured bedrock aquifers poses a challenge to the sustainable management of soils and water resources. The EU Water Framework Directive (WFD) attempts to achieve at least “good ecological status” for all water bodies by 2015. In Ireland and many other EU countries eutrophication due to nutrient enrichment is a major cause of poor status. The objective of the current preliminary study, conducted at a dairy research farm in the south of Ireland, was to estimate nitrate mass discharge in a fractured limestone aquifer. Direct discharge measurements were conducted to assess flow rates and nitrate discharge of karstic springs. A stream tube model was developed to assess the nitrate discharge in the fractured aquifer. The developed model estimated that up to 18 tons nitrate per year were being discharged from groundwater to the nearby river, which equates to 54% of the current total agronomic nitrate load on the farm.Key words fractured aquifers; karst; nitrate; discrete fracture network; dairy farming


Towards developing conceptual models for reactive contaminant transport in karst

MICHAEL SINREICHSwiss Federal Office for the Environment FOEN, CH-3003 Bern, Switzerland [email protected]

Abstract Conceptual models for reactive contaminant transport in karst groundwater must consider the reaction processes of specific contaminants in addition to the variable and complex flow regime. Due to insufficient information about the in situ relevance of attenuation processes, such concepts are in an early stage. A comparative tracing approach in conjunction with laboratory batch experiments allowed estimates to be made of attenuation in situ and on a

process-scale. Examples for solute and colloid tracing experiments in the vadose and saturated zones of Swiss karst aquifers are presented and the consideration of specific mechanisms, such as biodegradation, kinetic sorption and colloid exclusion, are discussed. Such experiments may provide the basis for the development of coherent conceptual models of specific contaminant types in karst systems, while considering the effectiveness of the processes involved in different recharge and flow components.Key words conceptual models; reactive transport; tracing tests; attenuation processes; karst


Particle density distribution measurements to control water quality of karst springs

DOMINIK BAENNINGER, ADRIAN AUCKENTHALER & NICOLE ITINDepartment of Environmental Protection and Energy, Canton Basel-Landschaft, Rheinstrasse 29, 4410

Liestal, [email protected]

Abstract Karst springs are often very vulnerable to microbial contamination after rain events. Beside microorganisms, typically discharge, turbidity, the spectral absorption coefficient at 254 nm (SAK) and the number of particles increase rapidly, with a long tailing after a rain event. Measuring these parameters would allow an increase of the security of the management system for drinking water. However, small water suppliers often do not have enough means to acquire measurement systems which measure all these parameters. Often, it is also not necessary to measure all parameters because they are redundant, or, depending on the karst system, weak proxy variables for microbial contamination. To support such water suppliers, we developed a mobile measurement system which can be installed for a certain period in the karst spring. After the measurement period, suggestions can be made to water suppliers on which parameter is most sensitive and thus should be measured to decide when the water quality declines. For a case study, we installed the mobile measurement system in a karst spring in the Canton Basel-Landschaft, Switzerland. Key words karst spring; particle density distribution; microorganisms


Estimating the vulnerability of karst springs to microbial contamination based on numerical flow modelling

CHRISTOPH BUTSCHER1, ADRIAN AUCKENTHALER2, STEFAN

SCHEIDLER1 & PETER HUGGENBERGER1

1 Department of Environmental Sciences, Applied and Environmental Geology, University of Basel, Bernoullistrasse 32, 4056 Basel, [email protected] 2 Department of Environmental Protection and Energy, Canton Basel-Land, Rheinstrasse 29, 4410 Liestal, Switzerland

Abstract An approach is presented to develop an indicator for the vulnerability of karst springs to faecal contamination. The indicator is expressed as the Dynamic Vulnerability Index (DVI) and determined by the ratio of conduit to diffuse flow contributions to spring discharge. DVI is calculated based on a numerical model simulating karst water flow. The performance of DVI to estimate the risk of faecal spring water contamination was tested at a karst spring in northwest Switzerland. Five recharge events were sampled at the spring, and analysed for faecal indicators (FI). The comparison of DVI with FI showed that maximum DVI values correlate with maximum FI levels by trend in this study. In addition, DVI was capable of giving an early warning of elevated FI levels in four of the five analysed events. It is concluded that DVI holds promise for the assessment of microbial pollution risks of karst springs.Key words karst hydrogeology; groundwater vulnerability; faecal indicators; numerical modelling


Development of groundwater salinity in the Wadi Zerka Ma’in catchment area, Dead Sea, Jordan

TALEB ODEH1,3, STEFAN GEYER1, MARIO SCHIRMER2, TINO RÖDIGER1, CHRISTIAN SIEBERT1 & RICHARD GLOAGUEN3

1 Helmholtz Centre for Environmental Research – UFZ, Department of Hydrogeology, Theodor-Lieser-Strasse 4, 06120 Halle-Saale, [email protected] 2 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department Water Resources and Drinking Water, Ueberlandstr. 133, 8600 Duebendorf, Switzerland3 TU Mining Academy Freiberg, Institute for Geology, Remote Sensing Group, Bernhard-von-Cotta-Strasse 2, 09596 Freiberg, Germany

Abstract Wadi Zerka Ma’in catchment area is located in the northeast of the Dead Sea basin. It has two different types of aquifers: (1) an unconfined upper limestone aquifer with groundwater level ranges between 800 and 160 m above sea level (asl), and (2) a confined lower sandstone aquifer with groundwater level ranges between 340 and –260 m asl. The two aquifers are separated by a marly aquiclude. The salinity in the carbonate aquifer ranges from 500 to 1500 µS cm-1, while the salinity in the sandstone aquifer is between 1.7 and 4.1 mS cm-

1. There is a major strike slip fault in the middle and lower part of the Wadi that passes perpendicularly through the two aquifers and the aquiclude layer with embedded normal faults. The aim of the study was to specify the origin, genesis, and development of the salinization of groundwaters, as a result of the major fault zone. It was found that the embedded normal form conduit connections produce a third groundwater type as a result of up-rising mixing. Therefore three groundwater types are generated in the flow as follows: (1) Alkaline – earth water predominantly bicarbonate (water group A) in the upper aquifer. (2) Alkaline – earth

water predominantly sulphate (water group B) in the mixing zone. (3) Alkaline – earth water predominantly sulphate-chloride (water group C) in the lower aquifer. Key words groundwater mixing; groundwater gneisses; saturation indices; trace elements; strike slip fault


Modelling and controlling of groundwater and salt movement in Yanqi basin, northwestern China

SHUIXIAN WANG1, XINGUANG DONG2 & BING WU3

1 College of Earth and Environmental Sciences, Lan Zhou University, 730000 Lan Zhou, [email protected] Xinjiang Institute of Water Conservancy, 830000 Urumqi, China3 College of Water Conservancy and Civil Engineering, Xinjiang Agriculture University, 830052 Urumqi, China

Abstract A three-dimensional finite-difference groundwater flow and salt transport model was implemented to investigate a variety of hydrogeological conditions and to simulate the behaviour of the flow system and salt transport under different scenarios in the Yanqi basin and to estimate the amount of pumped groundwater needed to evaluate the impact of different scenarios of varying extraction on the fluctuations of water levels. The models provide insight into the status and evolution of the groundwater and salt. The results of the study are useful to predict the sustainability of the groundwater resources in the Yanqi basin and to evaluate possible management actions.Key words groundwater; modelling; controlling salt; Yanqi basin, China


Groundwater as a driver of salinity in the Wybong Creek catchment, New South Wales, Australia

J. F. JASONSMITH1, B. C. T. MACDONALD2, D. C. MCPHAIL1, S. BEAVIS2, I. WHITE2, F. BISWAS2 & M. NORMAN1

1 Research School of Earth Sciences Australian National University, Acton 0200, Australian Capital Territory, [email protected] Fenner School of Environment and Society, Australian National University, Acton 0200, Australian Capital Territory, Australia

Abstract Wybong Creek is a 90 km-long tributary of the Hunter River, in the upper Hunter Valley of New South Wales, Australia. Previous research showed Na+-Cl- dominated water from Wybong Creek decreases the quality of the Hunter River. This study aimed to identify

the origin of solutes in the Wybong Creek catchment, in order to constrain salinity mitigation measures. Surface water was sampled at 10 sites along Wybong Creek. Groundwaters were sampled from most bores occurring in the Wybong Valley. Major ion analyses indicated that saline, Na+-Cl- dominated water rose abruptly in the mid-catchment area, with surface and groundwater in the upper catchment being dominated by fresher, Na+-Mg2+-HCO3

- type-water. Based on these findings, more intensive research including soil sampling and piezometer installation was conducted in the mid-catchment area. Results showed only slightly saline regolith, with up to 2185 mg TDS kg-1 soil occurring within a salt scald. Groundwater samples had up to 6960 mg TDS L-1. Ratios of Cl-/Br- and isotope ratios of 87Sr/86Sr indicated that this saline groundwater is influenced by both halite dissolution and a marine source, with a lack of δ18O enrichment indicating evapoconcentration has limited affects on salinity. The only marine and halite containing source of solutes occurring in the catchment is the Wittingham Coal Measures. Salinity therefore occurs naturally, with the dilution of Wybong Creek by other fresher tributaries the only practical means of limiting the impacts of salinity on water users downstream. Key words primary salinity; geochemistry; coal; groundwater


Assessment of groundwater quality in parts of the basement complex terrain of southwestern Nigeria

ABEL O. TALABI1 & MOSHOOD N. TIJANI2 1 Geology Department, University of Ado-Ekiti, Ado-Ekiti, Nigeria2 Department of Geology, University of Ibadan, Ibadan, [email protected]

Abstract Hydrochemical analyses of 73 groundwater samples from the weathered basement aquifer of Ekiti area, southwestern Nigeria were carried out with respect to drinking and irrigation quality assessment. Field measurements revealed EC of 43–1041 µs/cm, with total hardness of 8.3–349 mg/L CaCO3. The concentrations of the major cations appear in the order Ca2+>Na+>K+>Mg2+, with average concentrations of 32.5, 24.6, 24.5 and 8.6 mg/L, respectively, while that of the anions is HCO3

->Cl->SO42->NO3

- with average concentrations of 109.3, 57.9, 20.7 and 5.3 mg/L, respectively. Quality evaluation revealed a potable groundwater system suitable for both drinking and irrigation purposes. The overall estimated Water Quality Index (WQI) revealed that about 81% of the investigated water samples fall within the good to excellent category. The remaining 19% taken from wells located in the vicinity of waste dumps are classified as poor to unsuitable.Key words basement aquifer; groundwater quality; sodium hazard; Water Quality Index; irrigation water; southwest Nigeria

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