REPORT OF THE NICOLE WORKSHOP

Transcription

REPORT OF THE NICOLE WORKSHOP:
Operating windows for site characterisation
25-27 May 2011
Copenhagen, Denmark
www.nicole.org
Compiled by Elze-Lia Visser, secretary
NICOLE Service Providers Group and
Hans-Peter Koschitzky, academic member
NICOLE Steering Group
Report of the NICOLE WORKSHOP: Operating windows for site characterisation
Acknowledgements
NICOLE gratefully acknowledges
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Grontmij for co organising the event
The speakers and chairpersons for their contributions to the meeting and their comments on this
report
The members of the Organising Committee:
o Kristian Kirkebjerg, Grontmij, Denmark / chair Organising Committee
o Lucia Buvé, UMICORE, Belgium
o Wouter Gevaerts, Arcadis, Belgium
o Hans-Peter Koschitzky, VEGAS/University Stuttgart, Germany
o Sarah MacKay, WSP, UK
o Carla Schön, Electrolux, Sweden
o Mark Travers, Environ, France
o Elze-Lia Visser-Westerweele, NICOLE Service Providers Group, NL
The NICOLE secretariats
NICOLE is a network for the stimulation, dissemination and exchange of knowledge about all
aspects of industrially contaminated land. Its 120 members of 20 European countries come from
industrial companies and trade organisations (problem holders), service providers/ technology
developers, universities and independent research organisations (problem solvers) and
governmental organisations (policy makers).
The network started in February 1996 as a concerted action under the 4th Framework
Programme of the European Community. Since February 1999 NICOLE has been self supporting
and is financed by the fees of its members.
More about NICOLE on www.nicole.org
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Contents
1. Background
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2.
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Strategies for characterisation
2.1. Make a conceptual site model ............................................................................................. 5
2.2. Geophysics ........................................................................................................................... 5
2.3. Non destructive field screening methods ............................................................................ 5
2.4. Risk assessment volatile contaminants .............................................................................. 5
3.
Field techniques
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3.1. Purge and no-purge groundwater sampling ......................................................................... 6
3.2. Sampling material in stockpiles ........................................................................................... 6
3.3. Sampling in door air ............................................................................................................. 6
3.4. Mass discharge from DNAPL zones ..................................................................................... 6
3.5. Direct push techniques ........................................................................................................ 7
4.
Isotope analysis and DNA-analysis
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4.1. Isotopes ................................................................................................................................ 8
4.2. Natural attenuation of MTBE ............................................................................................... 8
4.3. Biotraps ................................................................................................................................ 8
5.
Forensics
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5.1. State of the art ..................................................................................................................... 9
5.2. Pharmaceuticals .................................................................................................................. 9
5.3. Tree sampling ....................................................................................................................... 9
6.
Overall conclusions and recommendations
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6.1. General conclusions ........................................................................................................... 10
6.2. Recommendations ............................................................................................................. 10
Page 3
Appendix 1. List of participants NICOLE Network Meeting on 24-27 May 2011,
Copenhagen, Denmark
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Appendix 2 List of speakers NICOLE Network Meeting on 24-27 May 2011,
Copenhagen, Denmark and provided links for more information on the subjects
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Appendix 3. Collated abstracts provided by speakers NICOLE Network Meeting on
24-27 May 2011, Copenhagen, Denmark
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1. Background
The NICOLE Network Meeting on 25-27 May 2011 explored the subject of Site Characterisation Tools,
and updated us on where they can provide value in the management of contaminated sites. We have all
heard anecdotally, or may have tried some of the myriad of new techniques and approaches being
proposed around the industry. From forensics using isotopes and DNA, to new drilling methods and
microbes - the range of options on offer may seem confusing.
From the ongoing work with the Soil Directive it is evident that some sort of baseline and monitoring will
be needed in the future and we find ourselves facing other new pieces of legislation such as the
Industrial Emissions Directive (IED) which may also have potentially onerous baseline monitoring
requirements. As such, our thoughts turn to the tools and methods we have for investigation, and
thought it was time to update ourselves with a state of the art review.
This meeting has drawn us away from the marketing literature and technique sellers, and via a walk
through the site conceptual model, explored and contextualised techniques appropriateness – for
example:
• What technical conditions does it operate under – for example under what lithological or
hydrogeological conditions can it actually operate and what are its limitations and ranges?
• In what circumstances will it add value - so for example is it only really warranted in a detailed
compliance defence, or will it help to speed up development or remediation?
A programme of invited speakers reviewed the current and recent techniques and possibilities for site
investigations such as drilling, sampling, in situ measurement and analysis for liquid, solid or gaseous
contaminants in the subsurface. Moreover tracer tests, geophysics and last but not least plants as a
pollutant diagnostic tool have been addressed. An entire days session was devoted to the development
of advanced diagnostic techniques looking at forensics, DNA, isotopes, microbes, pharmaceuticals, and
exploring some of the challenges in the analysis and the applicability both in corporate compliance
work, and in remediation. The speakers explored the operating windows of the current and developing
methods. The invited speakers presented lots of case studies also, showing where techniques are
useful, applicable, appropriate and value for money.
In this report you will find the conclusions of the Network meeting organised via 4 themes:
1. Strategies for characterisation.
2. Field techniques.
3. Isotope analysis and DNA-analysis.
4. Forensics.
On each theme you will find a list of conclusions drawn from the different presentations in the NICOLE
Workshop. In the appendix of this report the abstracts that have been provided by the speakers have
been collated. From the NICOLE website www.nicole.org the presentations and the programme of the
meeting can be downloaded. For further information on the presentations you can approach the
speakers, their contact information is listed in the appendix to this report.
This report reflects the conclusions of the NICOLE Workshop and the outcome of discussions. This
document doesn't necessarily reflect the opinion of NICOLE and/or individual NICOLE members or
member organisations.
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2. Strategies for characterisation
2.1.
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2.2.
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2.3.
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2.4.
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Make a conceptual site model
Heterogeneity in the soil must be taken into account in conceptualizing your site model.
Work from macro scale into micro scale
Choice of technologies for conceptualizing your situation is not “either … or ….” but “….and…..”.
Take all results into account and try to visualize into a conceptual site model via an integrated
approach.
It all starts with understanding geology…..
Key issue for all steps to follow is to develop and understand the conceptual site model.
Geophysics
Different geophysical methods can be used before drilling to visualize (to get an idea of) soil
properties.
Can in some specific cases be used for imaging contamination (DNAPL source zones in specific
situations), use with care and be aware of robustness of the (imaging) tools.
In case of use for imagining contamination: additional information is always needed for
interpretation. Inform yourself on the limitations of the specific methods.
Can in some cases also be used for monitoring progress in remediation.
Non destructive field screening methods
Non destructive methods can guide traditional sampling and as such optimize site investigation
strategies (drilling campaigns, prioritization of investigation).
Non destructive techniques can be divided in screening techniques (e.g. XRF, MIP, PID) and
geophysical techniques (e.g.GPR, EM, Medusa).
Can be quick method for determining the scale and boundaries of contamination.
Risk assessment volatile contaminants
Risk assessment of contaminated soil vapour intrusion for existing buildings can be done by
measurements; for new (to be developed) buildings modelling is the way of working; a lack of
reliable parameters often causes a gap in necessary information.
Models exist and differ from each other on used parameters and type of transport of the
contaminant and give a large range of results.
Choose your model site specifically.
Communication on risk assessment needs attention.
3. Field techniques
3.1.
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3.2.
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Purge and no-purge groundwater sampling
No purge sampling with Passive Diffusion Bags and Hydrosleeves has been tested in practice.
No purge sampling can effectively be used for long term monitoring.
No purge sampling can significantly differ from purged sampling, especially in low permeable
zones and DNAPL zones.
No purge sampling can give a better insight into the distribution of the contamination.
Based on the results the interpretation can be that in source zones passive sampling (no purge)
should be used for risk assessment instead of purged sampling: purging can mobilize free
phase droplets (interpretation, not proven yet).
In source zones purged sampling is to be used for remediation design.
In plume zones (dissolved concentrations) either technique will work.
More case studies are needed.
Based on the significance of the results and the consequences they could have in practice
investigation under controlled conditions (large scale in lab) is recommended.
Sampling material in stockpiles
Sampling covers a wide field, two examples have been worked out on sampling granular
material in stockpiles.
Way of sampling adds to (un)certainty to results.
Validation of the samples itself in practice is not feasible due to the huge amount of cost.
Lot of work has been reported in international standards.
Work in progress on decision support tool for reliable sampling.
Numerical tools / concepts may be useful for interpretation data from groundwater / soil
sampling.
Sampling in door air
Indoor sampling of in door air is affected by many factors: weather, geology, building properties,
characteristics of the pollutant and others.
Risk assessment has to be based on average concentrations which needs measurements of
indoor air over a longer period of time
Several devices (more or less mobile) are available to do measurements during a short or longer
period of time
Mass discharge from DNAPL zones
Evaluating planes and mass discharge instead of point measurements is an effective way of
characterizing the contamination and monitoring remediation.
Reliable methods for quantification of mass discharge exist.
Multi level sampling methods are needed to evaluate mass discharge in a control plane.
Hydraulic conductivity is the main parameter influencing mass discharge calculations.
Evaluation of the effective number of sampling wells related to the value of the mass discharge
is subject to optimisation to save money and time.
Uncertainty analysis of mass discharge is an important area for further development.
3.5.
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Direct push techniques
Can be used additionally to or instead of traditional sampling and is cost-efficient.
Direct push technologies are very suitable for applying dynamic work plans.
Give fast results that can be transformed into immediate action for further data acquisition,
sampling or monitoring and remedial installations.
Some Direct Push techniques are based on indirect measurements (parameters). These indirect
measurements need to be calibrated with respect to the parameters of interest.
Be careful in using equipment in multilayered aquifers: do not penetrate a sealing layer below a
contamination to avoid cross contamination or worse creating spreading of contaminants in a
less or not contaminated aquifer (which is also valid for every drilling).
It should always be considered that the sealing of the probing holes for some Direct Push
techniques are difficult or even not feasible.
A well-versed team is a requirement for its reliable application and for the interpretation of the
data.
4. Isotope analysis and DNA-analysis
4.1.
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4.2.
Isotopes
Isotope analysis is a powerful tool to evaluate natural and/or enhanced biodegradation of
different contaminants (proof of degradation and degradation rates).
Isotopes are sensitive parameters and experience is needed to be able to evaluate the
outcome.
Isotopes can be used to identify (additional) sources of contamination.
Isotopes can be used to conceptualize your site model (e.g. flow paths, degradation pathways)
Natural attenuation of MTBE
• Compound specific stable Isotope analysis (C and H isotopes) combined with DNA detection of
key enzymes can provide quick and direct information on degradation of MTBE (potential for
degradation, chemical or biological degradation, actual or historical degradation, degradation
rate).
• Molecular techniques (DNA and RNA) can be used to detect the presence or activity of MTBE
degrading bacteria.
• Outcome of isotope analysis and DNA detection needs validation with batch data and field data
from contaminated site.
4.3.
Biotraps
• Biotraps are a passive sampling tool that collects microbes over time and mimics the
environmental conditions in the soil.
• Biotraps loaded with labelled compounds can be analysed using molecular and isotope based
approaches and have proven to be a diagnostic tool for prediction of biodegradation to convince
authorities on early close down without additional monitoring
• The detailed strategy with contingency milestones in monitoring was agreed by the regulator on
basis of molecular biological tools to support traditional lines of evidence
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5. Forensics
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5.3.
State of the art
Different methods exist for forensic studies on contaminants.
Most common methods are fingerprinting, isotope analysis and evaluation of natural and
anthropogenic tracers (e.g. additives).
Can be used for finding sources of contamination (dating, localisation of spills), give insight in
conceptual site model and indications for natural attenuation.
Feasibility study and a careful assessment of accuracy and reliability of the results are
recommended.
Pharmaceuticals
Pharmaceuticals are emerging contaminants and emerging to be used as tracer for forensics
Certain pharmaceutical tracers may be useful for forensic purposes in some cases
Careful evaluation of expenses versus results to be obtained is basis for selection of this tool.
Increased understanding of PPCP fate/transport remains key for usefulness.
Tree sampling
• Tree sampling can be used for screening of certain contaminants and aging a contamination
• Tree sampling and analysis provides additional information to other characterization results.
• Trees accumulate contamination in sap and in xylem (tree sap is the fluid transported in xylem
cells of a tree).
• Phytoscreening focuses on the youngest tree rings (sap uptake of contaminants) and reflects
the current state of contamination in the root zone.
• Phytoscreening can be used for mapping certain contaminants.
• Dendrochemistry focuses on the annual rings of the tree (xylem) which reflect the changes of
the environment (contamination) in the root zone.
• Dendrochemistry can be used for age dating of contamination (forensic, source identification).
• Both tools request specialized use and evaluation. A few specialized laboratories are able to
execute the rather expensive analysis.
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6. Overall conclusions and recommendations
6.1.
General conclusions
The network meeting has shown a variety of possibilities to improve the conceptual model being the
basis for all following actions and decisions (risk assessment, remediation, long term monitoring,
baseline assessment....). Key conclusions from this meeting are:
• Many tools and for a good result are available: you have to think about and use different tools to
have good insight in your conceptual site model.
• The key solution is the right combination and reasonable use of different tools.
• All decisions for contaminated land management and remediation are made upon the data of
the site investigations: be aware of the importance of your data!
• It is possible to decide upon uncertainties, but always pose yourself the question: is the level of
uncertainties the level you can manage?
6.2.
Recommendations
Review with respect to changes in legislation
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Changes in legislation urge us to review current and new technologies for site characterization
and monitoring.
No purge sampling
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In source zones the usual purged sampling can be a better method for remediation design.
For delineation of plumes both purged and no purge sampling methods give reliable results.
For risk assessment no purge sampling could be the preferred method.
More case studies are needed to prove of disapprove the above statements.
Based on the significance of the results and the consequences it is recommended to start trial
investigations under controlled conditions (large scale in lab).
Appendix 1. List of participants NICOLE Network Meeting on
24-27 May 2011, Copenhagen, Denmark
Arakere, Suda
Argyrou, Elli
Bakker, Laurent
Bastrup, John Ulrik
Bayersdorf, Hartwig
Beddow, Helen
Bell, Rob
Bjerg, Poul
Blom, Marianne
Boronat I Rodriguez, Jordi
Burrows, Hazel
Buvé, Lucia
Camerani, Caterina
Constant, Sébastien
Couto, Felipe
Darmendrail, Dominique
Davidsson, Lars
Dixon, Nik
Dörr, Helmut
Dreiseitel, Martin
Drenth, Eize
Eisenmann, Heinrich
Ejdeling, Göran
Euser, Marjan
De Fraye, Johan
Garcia de la Rasilla, Mascha
Gevaerts, Wouter
Gous, Danie
de Groof, Arthur
Groot, Hans
Guibert, Pierre
Hallgren, Pär
Hart, Catherine
van Hattem, Willem
Heasman, Ian
Held, Thomas
Hertzmann, Daniel
van Houten, Martijn
Hübinette, Per
Jacobsen, Frank
Jacquet, Roger
Jubany, Irene
Kiilerich, Ole
Kirkebjerg, Kristian
Klaue, Bjorn
Kobberger, Gustav
Kolle, Marcel
Koomans, Ronald
Koschitzky, Hans-Peter
Langenhoff, Alette
Lee, Alex
Liljemark, Anneli
Lucassen, Pim
MacKay, Sarah
Madarász, Tamás
Maurer, Olivier
van de Meene, Chris
Page 11
LyondellBasell Industries
Adventus Europe
Tauw BV
GEO
Robert Bosch GmbH
Nuvia Ltd.
freelance journalist
Technical University of Denmark
ENVIRON Corporation
MediTerra Consultors Ambientals, S.L.
BP International
UMICORE
AkzoNobel
SPAQuE
Remedx
Common Forum
WSP Environmental
Grontmij
Dr. Dörr Consult GmbH
F&R Worldwide, SRL
Oranjewoud
Isodetect GmbH
Sweco Environment AB
NICOLE Secretariat
CH2M Hill
Eurofins Analytico
Arcadis Belgium NV
Dow South-Africa
Grontmij
Deltares
Environ
URS Nordic
Port of Rotterdam
Taylor Wimpey UK Ltd
Arcadis Consult GmbH
Witteveen+Bos
Structor Miljö Göteborg AB
Grontmij
Solvay S.A.
Centre Tecnológic de Manresa
EPA Denmark
Grontmij
Thermo Fisher Scientific
HPC
Dura Vermeer Milieu
Medusa Explorations BV
University Stuttgart
Deltares
WSP Environmental
ÅF-Infrastructure AB
Philips Real Estate
WSP Environmental
University of Miskolc
CH2M Hill France
SBNS
USA
Greece
NL
Denmark
Germany
UK
UK
Denmark
NL
Spain
UK
Belgium
Sweden
Belgium
UK
France
Sweden
Dixon
Germany
Romania
NL
Germany
Sweden
NL
UK
NL
Belgium
SA
NL
NL
France
Sweden
Sweden
NL
UK
Germany
Sweden
NL
Sweden
Denmark
Belgium
Spain
Denmark
Denmark
Germany
Germany
NL
NL
Germany
NL
UK
Sweden
NL
UK
Hungary
France
NL
Menoud, Philippe
Merly, Corinne
Mezger, Thomas
Moll, Ulrich
Nguyen, Frédéric
Nielsen, Pernille
Van Nieuwenhove, Karel
van Noord, Wilfred
Ooteman, Kevin
Øster, Per
Pals, Jan
Pellegrini, Michele
Pentel, Robert
Plaisier, Wim
van de Pol, Erwin
Polenka, Miloš
Polenková, Alena
Van de Putte, Wouter
Raben, Henry
Rajala, Päivi
van Riet, Paul
Schelwald-van der Kleij, Lida
Schmidtke, Joachim
Schön, Carla
Schreurs, Jack
Schrooten, Pieter
Sévêque, Jean-Louis
Shoesmith, Colin
Sinke, Anja
Slenders, Hans
Smeder, Maria
Smith, Jonathan
Sørensen, Majbrith
Spence, Mike
Van Straaten, Mark
Svensson, Håkan
Svensson, Janna
Thomas, Alan
Torin, Lena
Törneman, Niklas
Touchant, Kaat
Travers, Mark
Underwood, David
Undi, Tilly
Upton, Paul
Vanderhallen, Joris
Verhaagen, Paul
Visser-Westerweele, Elze-Lia
Voogd, Leon
van der Voort, Jack
Waters, John
Williams, Stephen
Wiltshire, Lucy
Page 12
DuPont de Nemours
BRGM
Akzo Nobel
LyondellBasell Industries
Université de Liège
MediTerra Consultors Ambientals, S.L.
Antea Group
AkzoNobel
MWH
A/S Dansk Shell
SBNS
Saipem
GDF SUEZ
ARCADIS
Witteveen+Bos
GEOtest a.s.
GEOtest Brno, a.s.
MAVA
Tauw
Närings-, trafik-, och miljöcentralen
Dow Benelux BV
NICOLE ISG Secretariat
ENVIRON Germany GmbH
AB Electrolux
Philips Environment & Safety
ERM
UPDS
National Grid Property Ltd.
BP International
Arcadis
Akzo Nobel AB
Shell Global Solutions
Grontmij
Shell Global Solutions (UK)
MAVA
KemaktaKonsult AB
ERM UK
Golder Associates AB
Vito
Environ
Shell International Petroleum Company
TOTAL RM
RSK Group Plc
Port of Antwerp
Grontmij
NICOLE SPG Secretariat
MWH
Ingenieursbureau Oranjewoud BV
ERM
Thermo Fisher Scientific
Honeywell
Switzerland
France
NL
France
Belgium
Spain
Belgium
NL
NL
Denmark
NL
Italy
France
NL
NL
Czech Republic
Czech Republic
Belgium
NL
Finland
NL
NL
Germany
Sweden
NL
Belgium
France
UK
UK
NL
Sweden
UK
Denmark
UK
Belgium
Sweden
Sweden
UK
Sweden
Sweden
Belgium
France
UK
UK
UK
Belgium
NL
NL
NL
NL
UK
USA
UK
Appendix 2 List of speakers NICOLE Network Meeting on 2427 May 2011, Copenhagen, Denmark and provided links for
more information on the subjects
Strategies for characterisation
Wouter Gevaerts, ARCADIS, Belgium <w.gevaerts@arcadisbelgium.be>
Frédéric Nguyen – Université de Liège, Belgium <f.nguyen@ulg.ac.be>
Henry Raben, Tauw, the Netherlands <henry.raben@tauw.nl>
Lena Torin, Golder, Sweden <Lena_Torin@golder.se>
Field techniques
Wouter Gevaerts, ARCADIS, Belgium <w.gevaerts@arcadisbelgium.be>
Frank Lamé, Deltares, the Netherlands <frank.lame@deltares.nl>
Majbrith Sorensen, Grontmij, Denmark <mls@gmcb.dk>
Poul Bjerg, Technical University of Denmark <plb@env.dtu.dk>
Hans-Peter Koschitzky, VEGAS, University Stuttgart, Germany <koschi@iws.uni-stuttgart.de>
Isotope analysis and DNA-analysis
Heinrich Eisenmann, Isodetect GmbH, Munich, Germany <eisenmann@isodetect.de>
Alette Langenhoff, Deltares, the Netherlands <Alette.Langenhoff@deltares.nl>
Alex Lee, WSP, UK <alex.lee@wspgroup.com>
Forensics
Helmut Dörr, Dr. Dörr Consult, Germany <mail@dr-helmut-doerr-consult.de>
Joachim Schmidtke, Environ, Germany <jschmidtke@environcorp.com>
Gustav Kobberger, HPC, Germany <gkobberger@hpc-ag.de>
Page 13
Appendix 3. Collated abstracts provided by speakers NICOLE
Network Meeting on 24-27 May 2011, Copenhagen, Denmark
State of the art on geophysics
Frédéric Nguyen, Université de Liège, Belgium
A key element in the remediation of contaminated sites is the ability to map and characterize the
contamination distribution, and to assess the efficiency of in-situ remediation actions at the site scale. These
tasks are more or less difficult depending on the degree of heterogeneity of the subsurface.
Geophysical mapping refers to the display of geophysical data and may provide qualitative information on
contaminants, such as their location or extent. Geophysical mapping allows to reach a greater lateral
coverage than drillings, with resolution ranging from a few centimeters up to several tens of meters,
depending on the investigated depth. Generally, the resolution is inversely proportional to the investigated
depth. Repeating a mapping in time may also provide information on the degradation of the contaminants if
the degradation process affects the relevant physical property.
Geophysical imaging, on the other hand, may provide information on the location at depths of contaminants
in the subsurface, on their concentration and eventually on their degradation. However, the retrieved
information is indirect. It goes through two main filters before delivering the desired property. The first one is
related to the transformation of the acquired geophysical data (e.g. traveltime or resistance) to the spatially
distributed geophysical properties (e.g. seismic velocity or bulk resistivity), usually refer to as images.
Geophysical images are numerical models obtained by the optimization of a certain number of criteria. The
most important one being that the model is able to reproduce the measured data. These models, as for all
numerical models, suffer from uncertainties and may also exhibit numerical artifacts. Fortunately, these
drawbacks can be avoided by designing properly the geophysical survey, and quantified using image
appraisal tools such as the resolution/sensitivity matrix or the depth of investigation index. The second filter
links the recovered geophysical property (e.g. magnetic susceptibility) to the parameter of interest (e.g. metal
content). These petrophysical relationships are generally obtained at the laboratory scale, where the studied
medium is well controlled and understood. When applied in-situ, the validity of these relationships which
depend on the physico-chemical of the environment and on scaling laws has to be verified in order to avoid
erroneous interpretation.
This talk will give an overview of state-of-the art geophysical methods applied to contaminated sites in order
to detect, map, characterize and monitor pollutants in the subsurface. We will review the relevance of
geophysics depending on the target, and the limitations associated with the methods. Several relevant case
studies will be presented and analyzed. We will also provide an overview of what to expect from geophysics
in the future with a few research examples in the subfields of biogeophysics and hydrogeophysics.
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Current trends for tracer techniques in environmental hydrogeology
Serge Brouyère, Université de Liège, Belgium
Tracer techniques have been applied for years for the characterization of contaminant transport processes in
groundwater, in different context ranging from the delineation of protection zones around groundwater
catchment areas to the quantification of groundwater fluxes and hydrodispersive processes in variably
saturated underground media.
The objective of the talk is to present an overview on tracer techniques as applied to groundwater quality
and pollution issues. A specific emphasis will be made on the applicability and potential of these techniques
with respect to contaminated sites and on recent and ongoing technological developments of a single well
tracer technique aiming at quantifying and monitoring groundwater and contaminant fluxes at such sites.
The presented concepts will be illustrated using field results and associated modelling exercise.
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Direct push technologies: Overview, Applications and Limits
Carsten Leven-Pfister, University Tübingen, Germany, and
Hans-Peter Koschitzky, VEGAS, University Stuttgart, Germany
Dr.
Carsten
Leven,
University
of
Tübingen,
Center
D-72076 Tübingen, Germany. carsten.leven-pfister@uni-tuebingen.de
for
Applied
Geoscience
Hydrogeology
Dr.-Ing. Hans-Peter Koschitzky, VEGAS, Research Facility for Subsurface Remediation, University of Stuttgart, D-70550
Stuttgart, Germany, koschitzky@iws.uni-stuttgart.de
Cost efficient and sustainable remediation, especially with innovative in situ remediation technologies,
requires detailed knowledge of the subsurface in view of the pollutant distribution and the hydrogeology. So
far commonly site investigations based on boreholes are used for the characterization of contaminated sites.
In most cases these methods are time consuming, costly and as a consequence the site characterization is
based only on a few drillings, i.e. investigations points, which results typically in insufficient information
about the “real” extend and location of the contamination.
An alternative approach for site investigation is the use of Direct Push (DP) technology. This technology
refers to a growing family of tools used to obtain subsurface investigations by pushing and / or hammering
small-diameter hollow steel rods into the ground. By attaching specialized probes to the end of the steel
rods, it is possible to conduct high resolution logging of rock parameters as well as to collect soil, soil gas,
and ground water samples. Using DP technology it is feasible to get very quick and on site information about
the three-dimensional pollutant situation. This information serves as a basis for decision about the ongoing
stepwise site investigation. So overall more information can be received at lower costs. Besides the broad
applicability of DP technology, it also allows for a target-oriented installation of monitoring equipment.
Due to the development of new powerful machines and tools, the application of DP technology increased
strongly during the last years and became a viable alternative to conventional methods for site investigation.
With the new generation of DP machines several sounding locations can be completed per day. Furthermore,
under ideal conditions (e.g. soft, unconsolidated sediments) depths of more than 50 m can be reached.
The presentation will give an overview about the various direct push technologies and will also show the
benefits of these techniques for investigation of contaminated sites exemplary from case studies.
DIETRICH, P. & LEVEN, C. (2006): Direct-Push Technologies. In: Kirsch, R. (Ed.): Groundwater Geophysics.
Springer. 321-340
LEVEN, C. WEIß, H. KOSCHITZKY, H.-P. BLUM, PH. PTAK, TH. DIETRICH, P. (2010): Direct Push Verfahren, ISBN 978-3510-39014-4, altlastenforum Baden-Württemberg e.V., Schriftenreihe, Heft 14
Page 16
Quantification of Mass Discharge from DNAPL sites in heterogeneous geological
settings
Poul Bjerg, Technical University of Denmark
P. L. Bjerg (plb@env.dtu.dk), M. Troldborg, Ida Vedel Lange; Marta Santos; P. J. Binning (Department of Environmental
Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark)
DNAPL sources with chlorinated solvents are a major threat to groundwater. Contaminant discharge
(mass/time) from contaminated sites is a useful metrics when evaluating the potential risk to downgradient
receptors such as water supply wells and surface water bodies. A recent development is the coupling
between contaminant source remediation and the plume response in order to assess the efficiency of site
remediation and to optimize the resources spent to fulfill certain regulatory demands.
In the field, the mass discharge migrating from a contaminant source is typically determined across a control
plane located downstream of the source and perpendicular to the mean groundwater flow. The uncertainty in
a field-estimated mass discharge is highly related to the degree of heterogeneity of the mass flux distribution
at this control plane. The more heterogeneous the mass flux distribution is, the finer the monitoring
resolution network should be to ensure that the unmeasured areas in the control plane do not influence the
estimate significantly. However, at most non-research field sites the number of monitoring wells is limited.
The degree of heterogeneity of the mass flux distribution at the control plane is caused by several factors,
where spatially and temporally varying flow conditions and complex contaminant distribution in the source
zone are considered most important. A quantification of the mass discharge and the associated uncertainty
should therefore account for all these factors. However, it is not easy to describe and model the influence of
such factors at a specific site, especially when data are sparse. Often the knowledge about e.g. the source
and the geological and hydrogeological settings is limited, which makes it very difficult to conceptualize
these elements and to incorporate them in a model. The previous studies of mass discharge uncertainty
have not taken the influence of different conceptual site models into account.
We present here the results of a major effort on development and application of mass flux estimates in
engineering and regulatory practice. The activities are related to two DNAPL contaminated sites in Denmark.
Mass flux fences have been established at both sites and detailed descriptions of geology and hydrogeology
exist. The monitoring of the mass flux fences was completed at site A in 2008 as a part of the risk
assessment. At site B the temporal and spatial variability of mass flux estimates were evaluated during 2008
and 2009 by use of traditional wells (30 screens) and multi level samplers in the core of the plume (100
sampling points). The mass flux dataset for both sites are used to develop and test various methods for
quantification of mass discharge and related uncertainties.
The presentation aims to give an overview of these activities and propose future challenges in the area.
Page 17
Chlorinated solvent contamination, difficulties in understanding mass
distribution, a case study
Pierre Guibert, Environ, France
Pierre GUIBERT, ENVIRON(1), www.environcorp.com
(1) ENVIRON France, Les Pléiades III - Bât. C - 320, avenue Archimède - 13857 Aix-enProvence cedex 3 – pguibert@environcorp.com
A past undetected leak from an underground solvent distribution tank system has lead to a significant
subsoil contamination by trichloroethylene (TCE). Leak has been estimated at approximately several hundred
tons of product over a 3-4 year period.
Following detection of leak, pump & treat wells as well as SVE were installed on source area to recover
product and mitigate exposure to on-site workers. Since, numerous site investigations and risk assessments
were engaged both on-site and off-site to better understand contamination distribution and evaluate
potential risks to third parties and the environment.
These studies highlight that contamination is limited in the unsaturated zone, whilst important in the
saturated zone and groundwater. TCE is observed as a dense non aqueous phase liquid (DNAPL) both on top
as well as within a silt layer present on and off-site.
Chlorinated solvents have migrated as a dissolved phase with the general flow of the shallow aquifer but
more specifically as both dissolved and DNAPL via a preferential pathway composed of backfilled historic
river bed, before flowing into the surrounding rivers. The dissolved plume extends beneath a mixed industrial
estate composed of mixed traditional, industrial activities and local municipal services.
This understanding of both the hydrogeological context and the distribution of the mass of DNAPLs was
achieved after years of investigation programmes combined with the results of the remediation programme.
Based on environmental media sampling at exposure endpoints (soil-gas, ambient air, groundwater, surface
water) risks to human health and the environment are below applicable acceptable risk levels.
DNAPL contamination within a complex hydrogeological context presents numerous challenges that will not
permit full remediation thus making it difficult to prepare Remedial Action Plan (“Plan de Gestion de Site” PGS), in accordance with French guidelines, which implies that source abatement must be achieved based
on technical cost-benefit analysis.
This project has highlighted the following challenges/difficulties associated with the presence of TCE as
DNAPL in a complex hydrogeological context:
• Numerous investigation techniques (monitoring wells, soil borings, soil gas borings, membrane interface
probe borings, seismic refraction, tracer tests) were used to identify and delineate DNAPL mass and
understand the complexity of the natural context. All of these studies present limitations and uncertainties
making the characterization of DNAPL source area or confirmation of the actual presence of free product
difficult even when suspected.
• With the presence of significant DNPAL in a complex hydrogeologic context partial recovery of free product
appears as the only technically feasible solution as long as human health and environmental risks are
controlled.
• Non-extracted DNAPL will continue to generate a dissolved phase that will maintain the
environmental impact at a long-term steady state. Long-term monitoring of various environmental media and
the installation of deed restrictions will be the key components associated with long term risk management
of the contamination.
Page 18
Sampling of vapour
Majbrith L. Sørensen, Grontmij, Denmark
The presentation will give an overview of sampling techniques for assessment of vapour intrusion in houses
and buildings. The presentation will give an idea about errors and other factors that influence your results
and thus your sampling scheme should reflect the present geology and hydrogeology.
•
•
•
•
•
•
Page 19
Description of various sampling schemes, focused on intrusion of chlorinated and other volatile
solvents.
How are major and minor sources of error affect sampling and measurements. Absorbant media,
passive sampling, humidity, air pressure, geology.
How sampling can affect risk assesment. When to sample or wait?
Sampling with MIP, geoprobe and other field methods. Flux chamber and other quantitative
methods.
Description of typical case where sampling method can be essential for results
New upcoming sampling methods
Risk Assessment of Vapour Intrusion, focused on Chlorinated Solvents
Lena Torin, Golder, Sweden
Lena Torin, Golder Associates AB, Lilla Bommen 6, 411 04 Göteborg, Sweden
lena_torin@golder.se
The issue of soil vapour intrusion from volatile contaminants in soil and groundwater into buildings, and
especially chlorinated solvent chemicals, is becoming increasingly important in the world. In order to predict
which sites might have a vapour intrusion problem, several countries have developed models and/or
demand that soil gas and indoor air is sampled at the site. The different European countries do not have the
same view and approach to this issue and it’s therefore difficult to present a view of how risk assessment of
vapour intrusion is done in Europe. The presentation will therefore focus on current best practice and what
should be avoided.
The presentation will give a short introduction on how risk assessment of vapour intrusion is done in general.
The presentation will focus on vapour intrusion of chlorinated solvents as these chemicals make up most of
the vapour intrusion problems. This is because chlorinated solvents can form large plumes within the
groundwater, are persistent, have limited biodegradation in the vadose zone and are harmful to humans at
very low concentrations.
The presentation will cover the following topics:
Page 20
•
Quality control of sampling data and the importance of developing a conceptual site model to
understand variability and evaluate representative data for the risk assessment. What conditions
pose a risk for underestimating the risk?
•
When and how to use toxicological reference values, guidelines and occupational exposure
standards. Trends and differences between countries. Since December 2010 the classification
and labeling of certain substances within the EC are harmonized in the CLP/GHS-database.
•
How does the use of the building affect the risk assessment? The different exposures for
residential land use compared to commercial or industrial uses. What impact do building volume
and ventilation rates have?
•
Differences between some vapour intrusion models with regard to parameters and how validated
they are against empirical sampling data. The largest collection of empirical data assembled is
the USEPA vapour intrusion empirical database (http://iavi.rti.org).
Forensics - state of the art and possibilities in contaminated sites management
Helmut Dörr, Dr. Dörr Consult, Germany
Dr. Helmut Dörr
Dr. Helmut Dörr Consult, Germany – www.dr-helmut-doerr-consult.de
The general applicability, the investigation strategy and the benefits of forensic methods in contaminated
site management are discussed. Results are presented from a case study (TPH-, BTEX and PAHcontamination in soil and groundwater) at an industrial site occupied by various tenants over several
decades. The results are discussed with respect to the objectives of forensics of identifying the polluter(s).
The most common and approved forensic methods are the so-called fingerprinting, isotopic methods, the
evaluation of multi-element distribution patterns and the investigation and interpretation of trace substances
(e.g. additives) and environmental tracers.
Forensic methods are particularly suitable for the dating and localization of spills containing mineral oil and
aromatic hydrocarbons. The source of contamination can also be investigated for selected heavy metals and
CHCs. Other methods such as the determination of isotope ratios of pure substances and elements (Sr, Nd,
Pb and U) can be used for the differentiation of pollutant sources, to determine the region of their origin.
Nitrogen, boron and chlorine isotopes can be used to distinguish natural from anthropogenic sources. The
analysis of tree cores allows a dating of spills (phytoscreening, dendrochemistry and dendrochronolgy) under
certain conditions.
Forensic methods are not only suitable to identify polluters (location and date of spills) but can also add
value in developing the site model for site specific risk assessment. Moreover, the identification and
quantification of microbial decomposition potential can be a great benefit in the evaluation of cost efficient
remediation strategies (MNA concepts).
The application of forensic methods and interpretation of forensic data are demonstrated by a case study.
TPH-, BTEX- and PAH - fingerprinting together with data for MTBE and other specific chemical substances
(MEK, Bitrex, Cyclohexan and Sulfur were suspected from a Phase I investigation) allowed the identification
of locations and dates of spills of gasoline, heating oil/diesel, and heavy oil spills with differing accuracies of
discrimination. Additionally, CFCH-, SF6- and tritium analyses were evaluated to describe the hydrogeological
structure (contaminant transport behaviour, mean residence time, infiltration rates) of the contaminated
aquifer for a risk assessment process.
Page 21
Isotopes in contaminated sites management - principles and recommendations
Heinrich Eisenmann, Isodetect GmbH, Munich, Germany
The redevelopment of contaminated sites demands the application of efficient remediation technologies.
Within this scope, the monitoring and enhancement of natural attenuation processes is a key strategy.
However, clear evidence for biodegradation has to be provided. Isotope analysis delivers key information
about contaminated sites. The isotope fingerprint of pollutants can allow discrimination of the initiators of
groundwater contamination, while the enrichment of heavy isotopes by biological degradation can elucidate
natural attenuation processes.
In situ biodegradation at contaminated sites can be assessed by the enrichment of heavy stable isotopes
(13C, 2H) in the residual pollutants. In many cases, even the quantification of biodegradation is possible,
because of correlation to isotope enrichment. The appropriate isotope enrichment factor has to be selected
according to the compound of interest and prevailing redox conditions (see www.isodetect.de). As a
consequence, isotope monitoring can provide detailed information on natural attenuation processes by a
single sampling campaign. The percentual decrease of contaminants caused by micobiological activity
downstream from the source as well as biodegradation rates can be derived. This enables also the
discrimination of non-sustainable processes that further diminish contaminant concentration such as
dilution or dispersion.
Numerous examples for successful isotope monitoring at sites contaminated with BTEX, MTBE or chlorinated
ethenes have been described in scientific reports. As next, guidelines for this powerful exploring technique
have been published by several environmental authorities. The presentation gives an overview about the
state of the art in isotope monitoring of contaminated groundwater. In case studies, the quantification of
biological attenuation of BTEX and chlorinated ethenes is demonstrated. For forensic purposes, the isotope
fingerprint of pollutants can allow discrimination of the initiators of groundwater contamination. Finally, a
variety of supplemental isotope surveys such as two-dimensional isotope monitoring (13C, 2H, 37Cl), isotope
enrichment of electron acceptors (NO3 and SO4), and the exposition of isotope-labeled in situ microcosms
(BACTRAPS) is shortly explained.
•
•
•
•
•
•
•
Page 22
Meckenstock, R., et al (2004) Stable isotope fractionation as a tool to monitor biodegradation in contami¬nated aquifers.
J. Cont. Hydrol. 75: 215-255.
US-EPA (2005) Monitored natural attenuation of MTBE as a risk management option at leaking underground storage tank
sites. EPA/600/R-04/1/179. www.epa.gov/ada/download/reports/600R04179/600R04179-fm.pdf
DECHEMA (2007) Held, T. et al.: Handlungsempfehlung: Mikrobiologische NA-Untersuchungsmethoden. www.naturalattenuation.de/media.php?mId=5623
Fischer, A., Theuerkorn, K., Stelzer, N., Gehre, M., Thullner, M. Richnow, H.H. (2007) Applicability of Stable Isotope
Fractionation Analysis for the Characterization of Benzene Biodegradation in a BTEX-con¬taminated Aquifer.
Environmental Science & Technology 41: 3689-96.
US-EPA (2008) A Guide for assessing biodegradation and source identification of organic ground water contaminants
using compound specific isotope analysis (CSIA). EPA 600/R-08/148.
www.epa.gov/ada/pubs/reports/600r08148/600R08148.html
KORA (2008) Michels, J., Stuhrmann, J., Frey, C., Koschitzky, H.-P.: KORA Handlungsempfehlungen: Natürliche
Schadstoffminderung bei der Sanierung von Altlasten. DECHEMA 2008. www.naturalattenuation.de/content.php?_document[ID]=6947&pageId=2647
Eisenmann, H. Fischer A. (2010) Isotopenuntersuchungen in der Altlastenbewertung. Handbuch der Altlastensanierung
60:3511.
Closing down of remediation using Biotraps and DNA analysis – a case study
Alex Lee, WSP, UK
Advanced diagnostics and forensic techniques are broadening the scope of site investigations and
expanding the lines of evidence available to soil and groundwater practitioners, problem owners and
regulators. Some of the more popular and widely available techniques include the following:



Molecular Biological Tools – DNA / RNA analysis to characterise microbial populations and degradation
processes. Can be used to provide clear lines of evidence to support theories of contaminant
degradation via microbial processes;
Compound Specific Isotope Analysis – analytical processes that analyse the molecular weighting of
contaminant species in order to assess degradation processes. These analytical methods can be used
to provide evidence of contaminant degradation;
Groundwater tracers – tracers comprising DNA strands or physical dye tracers can be used to evaluate
groundwater flow paths giving greater confidence and understanding of groundwater flow regimes
We present a review of the above techniques and a summary of different situations where they have been
used in real life cases. Concluding from the case studies, we suggest where the techniques can be useful –
what ‘operating windows’ or situations are appropriate.
We also use case studies to demonstrate the value to the problem owner and regulator that such techniques
can bring in early close out of long term remediation schemes, saving time and money, but providing
additional lines of evidence to allow regulatory close out.
Rather than being ‘out of reach techniques’ which are only available to the few and at high cost, we show
how some of the more useful and accessible emerging methods are being used routinely to close out long
term monitoring programmes.
Page 23
Analytical challenges – It all starts with sampling
Frank P.J. Lamé
Deltares – The Netherlands
In testing the environmental quality of a site, the investigation follows a series of steps: planning of the
sampling campaign, fieldwork including sampling, packaging of the sampled material, sample selection
for analysis, pre-treatment of the sample, extraction or destruction of the sample, chemical analysis and
reporting. Each of these steps can give cause to errors, while every error can contribute to a biased
result and consequently might result in an incorrect conclusion about the environmental quality of that
site. High costs might be involved for remedial actions while there still is a lot of uncertainty about the
nature, extent and level of contamination.
Much emphasis is given to the analytical part of the characterization process: the reduction of the
analytical error by means of e.g. calibration of the analytical equipment, blank samples, certified
standards and round robin tests. Less attention is given to the origin of the analysed material, the
sample, and the sampling strategy through which it was obtained.
A site investigation is based on assumptions about the environmental quality of that site, wherein the
assumptions are based on information obtained on the history of the site, the processes on the site and
the risks for these processes to have either contaminated the soil and / or the groundwater. A
conceptual model of the site builds up in the mind of the consultant, and during the investigation
process, this conceptual model should develop to such a level that it is sufficiently clear to come to
decisions about the site. National, as well as international standards (e.g. ISO 10381-5) provide
guidance for the sampling of contaminated sites.
As the sampling strategy is based on non-statistical information (the assumptions about the site), the
accuracy of the overall process cannot be simply calculated. Indeed, the question arises if validation of
the overall procedure is even possible.
Another issue is the characterization of a lot or stockpile of soil or soil-like material. What is the
environmental quality of that material and can it be reused safely, or is treatment necessary prior to its
reuse? Is it even possible to obtain a reliable estimate of the mean concentration of such a, potentially
highly heterogeneous, lot? How many samples should be taken and what size (mass / volume) should
the samples have? How can you ensure that the 2 grams analysed for heavy metal content are actually
representative for a soil lot of, for example 2000 tons? In such cases assumptions about the past of the
material are of less relevance, at least for the sampling strategy to be applied. A statistically based
approach van be used which allows at the same time the quantification of errors made. For the
sampling of soil stockpiles, a unique validated sampling strategy has been developed.
Page 24
Pharmaceuticals in groundwater bodies as a forensic tool
Joachim Schmidtke, Environ, Germany
Over the past decade, pharmaceuticals and personal care product (PPCP) compounds have been identified
and studied as emerging pollutants. Although many studies have been conducted regarding the presence of
PPCPs in sanitary wastewater and the environment, these studies have been primarily focused on evaluating
the extent, fate, and toxicological significance of PPCP discharges. For comingled environmental
contamination in areas where multiple potential sources exist, PPCPs also have the potential to serve as
forensic indicators of contaminant sources. Because public use of many PPCPs can be tracked to a specific
date of drug regulatory approval or initial date of manufacture and trends exist for use of certain popular
products, PPCP data can also be utilized in age dating analyses.
Ideal PPCP forensic indicators include persistent and mobile compounds that are in widespread usage in the
population of interest. Wastewater sources that treat flow from multiple sources have an increased
likelihood of the presence of a variety of indicator chemicals, although many compounds have also been
identified in septic system discharges. Water quality studies conducted to identify the extent of the PPCP
problem have detected a range of candidate compounds and have provided detection frequency data useful
in selecting target compounds. Follow-on studies have provided additional data regarding of the persistence
and fate of these compounds in surface and ground water environments, as well as survival in various
wastewater treatment processes prior to discharge to the environment.
Page 25
Tree sampling for Environmental Forensics
Jean-Christophe Balouet * & Gustav Kobberger **
Two methods are presented, both based on chemical analyses of wood samples from trees:
1. Phytoscreening
Because trees uptake pollutants to which they are exposed, they can be used as indicators for pollutant
releases in their vicinity. Soil and groundwater contaminants are uptaken and transported by sap in the
outermost wood rings. These can easily be micro-sampled (0.2 g) and analyzed for the sap enriched
contaminants. This method allows to qualitatively and quantitatively identify or exclude the presence of
underground contaminants such as Chlorinated Hydrocarbons (PCE, TCE, DCE …). The correlation coefficient
between tree and underground contamination is respectable (and up to 0.9). Whenever a site is properly
vegetated, Phytoscreening can be used for a rapid identification or exclusion of contamination, for clarifying
contaminant distribution by fast low cost measurements, for identification of release spots and delineation
or monitoring of plumes. Being a standard method for CVOCs, BTEX and heavy metals (Cd, Cr, Cu, Hg, Ni, Pb,
Zn) PIT currently investigates, if this method is also suitable for PAH, PCB and other organic compounds.
2. Dendrochemical Age-Dating
Due to their seasonal growth annual tree-rings represent a bio-archive of the past. During this growth
process elements taken up with the sap from the rhizosphere are being built in and fixed to wood cells.
Accordingly and besides heavy metals pollutant specific tracer elements such as Chlorine (for chlorinated
organic compounds like PCE) or Chlorine and Sulfur (for Fuel Hydrocarbons) are built in and fixed to the wood
cells. This growth related element incorporation exclusively takes place within the youngest annual ring with
the resulting element concentration depending on the respective element availability in soil and
groundwater. The change in concentration over all annual rings of a tree core sample from the stem can be
gained for 30 elements with the help of energy-dispersive X-Ray-analysis (ED-XRF). The ED-XRF is supported
by a line scanner allowing an equidistant scan of a complete wood core from its youngest to its oldest ring at
increments of 50 µm. This process delivers the concentration profiles of 30 elements over the total life time
of a tree can be obtained at a very high temporal resolution. Accordingly, concentration anomalies of
pollutant specific elements (tracers such as Chlorine) can be dated exactly to reveal the beginning and
duration of an underground impact (such as by PCE). In order to rule out or confirm the possibility of
alternative sources for the Chlorine anomalies (e.g. road salt), allied element concentration profiles (e.g. K,
Ca, Mg, S) are compared for Cl-synchronous anomalies (multi-element-analyses). Other potential
(environmental) influences are assessed by comparison with a sample taken from a control tree in the
vicinity outside of the polluted area. By this means tree core samples can be used as „proxy-recorders“
documenting historic pollutant releases and impacts. If further historic data (e.g. documents) and
information on soil and groundwater are considered, this method provides a reliable and very exact dating of
the impact (by one 1 year) at the tree’s location. If more trees are available the spatiotemporal expansion of
a plume as well as contaminant transport velocities can be revealed. This method is a powerful tool that
provides an independent line of forensic evidence when attributing damages to polluters by exact age dating
of impacts.
* Environment International, 2 ruelle du Hamet, 60129, France (jcbalouet@aol.com)
** HPC HARRESS PICKEL CONSULT AG, Kapellenstr. 45a, 65830 Kriftel, Germany (gkobberger@hpc-ag.de
Page 26
Isotopes and Microbes; a fruitful couple to prove natural attenuation of MtBE
Alette Langenhoff, Deltares, Netherlands
Alette Langenhoff, Jan Gerritse and Harry Veld
Deltares, P.O. Box 85467, 3508 AL Utrecht, the Netherlands, www.deltares.nl
Innovative monitoring tools are important for site characterisation, remediation studies or full site remediations.
In complex situations, they can be crucial to understand the processes that occur at these sites, especially when
routine monitoring (eg redox parameters, concentration of the contaminants) do not give sufficient insight in
these processes. Furthermore, they can be applied at sites with insufficient progress in their bioremediation.
The following monitoring tools can be applied
1. Compound specific stable isotope (laboratory analyses on groundwater samples or pure product);
2. Bacteria and enzymes (DNA or RNA analyses on genes in soil- or groundwater samples);
3. Hydrogen (field analyses on groundwater samples).
The presentation will explain the tools, and their efficient use with a focus to proof Natural Attenuation (NA) of
methyl tert-butylether (MtBE). MtBE is an oxygenate added to fuel to improve combustion and reduce emissions
of carbon monoxide and unburned hydrocarbons. The massive production and use of MtBE, combined with its
high mobility and low intrinsic degradation rates make MtBE an important groundwater pollutant. We currently
use the first two detection methods to provide quick and direct tools as indicators for NA of MtBE.
Isotopes Biodegradation results in fractionation of carbon and hydrogen isotopes in the remaining MtBE. We
used a relatively new “Stir Bar Sorptive Extraction” or “Twister” technique to determine stable carbon isotope
ratios on low concentrations of MtBE and its metabolites, TBA and TBF (if present), and stable hydrogen isotopes
of MtBE. On a contaminated site, stable carbon and hydrogen isotope analyses suggested aerobic degradation of
MtBE.
Microbes We have designed quantitative real-time PCR assays to detect genes of key enzymes involved in
biodegradation of MtBE, MtBE-monooxygenase or isobutyryl-CoA mutase, respectively (Fig 1). We detected
different concentrations of these MtBE-degradation genes in cultures of MtBE-degrading bacteria and
groundwater from contaminated sites.
CH3
CH3
H3C
CH3
(A)
methyl tert-butyl ether
(MtBE)
Figure 1
H3C
C O CH3
C OH
CH3
tert-butyl alcohol
(TBA)
CH3
H3C C C
OH
CO2 + H2O
O
OH
+
(B)
Biomass
2-hydroxyisobutyric acid
(2-HIBA)
Degradation of MtBE, with the key enzymes for MtBE degradation: MtBE monooxygenase (A) and
Isobutyryl-CoA mutase (B)
At contaminated sites, the presence of MtBE, TBA and isotopic fractionation correlated with the presence of
MtBE-degradation genes. Statistical analyses showed a strong correlation between the concentration data, stable
isotope analyses and the quantity of MtBE degradation genes.
Page 27
Non destructive screening tools: overview, case study, relation with guidelines
Henry Raben, Tauw, the Netherlands
In soil and sediment studies, geophysical mapping is often used as a prerequisite to focus or guide
traditional sampling and coring to the locations of interest. This way, synoptic and concise information on
structure, composition and pollution of soils and sediments can be obtained.
Geophysical mapping or non-destructive site investigation gradually becomes more standard in site
investigation for environmental impact assessments. Case studies show the benefits when searching for
pollution in brown field sites, dumping locations, spreading of polluting aggregates in roads and the
dispersion of pollutants in underwater sediments. Technologies as ground penetrating radar, gamma
spectrometry, EM, XRF, mobile gas chromatography have been used for decades in the oil & gas industry
and mining business but the application in soil investigation is relatively new. One of the reasons for this late
application in environmental site investigation is the legislation that commonly prescribes how many drillings
and samples should be taken at which locations. However, recent adaptations of this legislation for example
in the Netherlands have created opportunities for the use of non-destructive site investigation in
environmental assessment studies. Also the International en European standardisation organisations
(ISO/CEN) are working on a general framework for the validation of screening technologies. Under this
framework the XRF will be the first technology were an ISO standard will be published.
The presentation gives an overview of different technologies that are useful in soil and sediment assessment
studies. The basic principle of the technology and the opportunities for application will be explained. The
beneficial value of using non-destructive techniques is explained by a case study. Ground penetrating radar
and XRF are used in the case study to preselect locations for traditional sampling methods. By using these
techniques the drilling plan was optimized, the site was investigated in a shorter period of time which
resulted in lower costs in contrary to the approach according to existing guidelines. The traditional sampling
methods were mainly used to calibrate and verify the results of the non-destructive technique and to
convince the public authorities.
Page 28
Page 29
Previous NICOLE Network Meetings
State of the art of (Ecological) Risk Assessment, Stockholm, Sweden
The impact of EU Directives on the Management of Contaminated Land,
Cagliari, Sardinia, Italy
Data Acquisition for a Good Conceptual Site Model, Carcassonne, France
16-17 June 2005
1-2 December 2005
10-11 May 2006
Making Managmenet of Contaminated Land an Obsolete Business –
Challenges for the future (NICOLE 1996-2006 Ten Year Anniversary
Workshop), Leuven, Belgium
5-6 October 2006
Redevelopment of sites – the industrial perspective. Akersloot, the
Netherlands
14-15 June 2007
Using baselines in liability management: what do upcoming Directives
require from us? Brussels, Belgium
Sustainable Remediation, London, UK
Environmental Decision Support Systems, Madrid, Spain
Basics and Principles of Environmental Law, Brussels, Belgium
Sustainable Remediation - A Solution to an Unsustainable Past? Leuven,
Belgium
From Site Closure to Disengagement, Douai, France
Contaminated land management: opportunities, challenges and financial
consequences of evolving legislation in Europe, Triest, Italy
Emerging contaminants and solutions for large quantities of oil
contaminated soil (Technical meeting), Brussels, Belgium
15-16 November 2007
3 March 2008
9-10 October 2008
31 March 2009
3-5 June 2009
18-20 November 2009
5-7 July 2010
4 November 2010
For a complete overview of all networks meetings that have been held from the start of NICOLE up to
now see www.nicole.org.
Page 30

REPORT OF THE NICOLE WORKSHOP

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