Final Report Summary - MODELPROBE (Model driven Soil Probing, Site Assessment and Evaluation)
Conventional techniques for site characterisation are time consuming, cost intensive, and often do not support decision making with regard to sustainable remediation. Therefore, new techniques for step by step site characterisation with smart feed back loops are necessary that are able to support a future soil Framework Directive.
Advanced geophysical site characterisation techniques combined with new types of vegetation analysis were developed. Based on these non-invasive surveys, the extension of sources, contamination levels (THP, BTEX, PAH, CHC, explosives, and heavy metals) and soil heterogeneities can be localised first. Hot spots will then be investigated by new direct push probing systems integrated with geophysical and hydrogeological methods and combined with chemical and isotopic contaminant analysis for source localisation and identification (environmental forensics). The actually occurring bioprocesses, such as contaminant degradation or sorption and mobilisation processes, are assessed using biosensors, in situ microcosms and stable isotope and biomarker analysis. These new techniques and tools were evaluated against best practice of conventional methods and the results are documented in the MODELPROBE handbook in addition to more than 45 scientific publications (ISI).
The MODELPROBE project provided the opportunity to test, optimise and demonstrate the proposed approach at fully equipped and characterised European brownfield reference sites in Germany, Italy, Norway and the Czech Republic. Integrated statistical analysis and modelling at different stages, the step by step approach resulted in an improved view of soil and subsurface contamination and provides a sound basis for a cost-effective risk assessment and decision in the choice of the most appropriate sustainable remediation strategy.
Project context and objectives:
Conventional techniques for site characterisation and management are mostly made of unrelated tasks (site history assessment, drilling, sampling, chemical / toxicological analysis, consulting, risk assessment, and remediation action). This approach is highly expensive, extremely time consuming and currently is not directed to supporting the decision making at an early project stage. Present techniques are not suitable to trigger effective assessment, management and remediation actions and therefore, need integration. In particular, they are mostly not compatible with a future soil Framework Directive planned to follow up the present soil thematic strategy of the European Commission (EC).
In particular, current conventional site assessment techniques do not cover screening of potentially contaminated sites, source analysis regarding environmental forensics and most methods are not suitable to be extended towards remediation monitoring. In addition, the present state of the art in geological site assessment requires generally some kind of drilling with the corresponding costs and effort resulting in low area coverage. Therefore, innovative flexible and minimal invasive types of geo-sampling were required at the beginning of the project.
As a consequence, improved technologies and tools for step by step site characterisation with smart feedback loops are necessary and were developed in between by the MODELPROBE project and also outside. These new techiques support the upcoming soil Framework Directive planned by the EC. Within the framework of the MODELPROBE project, a combination of advanced geophysical site characterisation techniques with new types of low-cost vegetation analysis have been developed. Based on these non-invasive surveys, the extension of sources, contamination levels and soil heterogeneities can be localised first. Hot spots will then be investigated by novel direct push probing systems including geophysical and hydrogeological methods combined with chemical and isotopic contaminant analysis for source localisation and identification (environmental forensics). Bioprocesses such as bioavailability, contaminant degradation or sorption or remobilisation processes can now be assessed by biosensors, in situ microcosms, stable isotope and biomarker analysis.
Novel techniques and tools, however, always need to be evaluated against best practice of conventional methods. Therefore, the new tools were applied in parallel at fully equipped and characterised European reference sites available for the MODELPROBE consortium (Trecate and Rho, Italy; Zeitz in Germany; Mimon / SAP, Czech Republic; Moeringa, Norway; for details see MODELPROBE homepage: http://www.MODELPROBE.eu online). These sites have been equipped in previous projects or by other national sources (European Union (EU)-funded projects: BIOTOOL, WELCOME, BIOISOTOPE; German BMBF-projects: RETZINA, SAFIRA, and several others). Integrated statistical analysis and modelling at different stages of the step by step approach resulted in an improved view of soil and subsurface contamination and provided the sound basis for risk assessment decision. The developed tools are now provided as guidelines and operation manuals and are available to industry, small and medium-sized enterprises (SMEs), consultants, and authorities for application within the framework of the MODELPROBE handbook.
Objectives:
A step by step characterisation approach for contaminated sites comprise an inherent feedback loop strategy that allows referring back at each stage to the results of previous stages. This approach helps minimising the effort and providing sufficient information necessary for a decision at each point. This approach requires operation manuals of the specific analytical tools that are related to each other and, what is more important, an integrated statistical analysis of the geological, geophysical, chemical, biotic and ecotoxicologial data aiming at a three-dimensional (3D) modelling of the contamination at a site derived from a minimal data set. This concept provides a very high cost / efficiency ratio for site assessment.
Since new methods need to be validated properly before being considered resistant to a legal scrutiny, the developed techniques and combined tools in the MODELPROBE project are related to conventional assessment techniques. However, the effort required by such comparison would require a separate project. Therefore, the MODELPROBE approach was tested at fully equipped European reference sites that were characterised by the necessary suite of drillings, chemical inventory and hydrological modelling, and subjected to continuous monitoring or even operating remediation measures. In addition, the implementation of new approaches always required training of users, consultants, decision makers, authorities, and even of environmental lawyers. This requirement was also an inherent part of the project. General objectives of the project were the following:
- To develop and improve a set of new, relatively simple-to-use and minimally or non-invasive methods for the assessment of contaminated soils in the framework of the soil thematic strategy. This set of methods should provide a toolbox for future application in the planned soil Framework Directive for the general purpose of contaminated site characterisation and monitoring of remediation progress. The following issues are addressed:
- general site characterisation and (hydro-)geology (vegetation analysis, geophysics, and direct push);
- analysis of biogeochemical conditions (direct push with new approaches);
- analysis of contaminants (plant based primary assessment or monitoring, direct push with new approaches, isotope analysis);
- assessment of ecotoxicology (passive samplers, toxicity testing, effect based analysis);
- analysis of sources (isotope analysis with environmental forensics);
- assessment of microbial degradation activity and contaminant bioavailability (compound specific stable isotope fractionation analysis, in situ microcosms, e.g. BACTRAP and fuel cell meter).
- To evaluate the methods against conventional technologies at fully characterised sites (Zeitz, Germany; SAP, Czech Republic; Trecate and Rho, Italy).
- To evaluate the methods as appropriate information sources for long term monitoring purposes and to assist Monitored Natural Attenuation measures.
- To provide additional modelling tools for integrative assessment.
- To provide guidelines for applying the new tools in order to instruct decision makers, consultants and users with the chances and limitation of the new tools.
Transformation of the general objectives into specific ones of the reporting periods:
The general objectives for the first period were to implement the project and to find the appropriate language and communication strategies for the various disciplines working together in the project.
The objectives for the first reporting period are:
1. to evaluate the validity, chances and limitations of the various methods, in particular the new geophysical ones;
2. to check how the methods can be applied non-invasively or be combined with direct push techniques;
3. to evaluate how spatio-temporal statistical methods can be applied to the data of the various methods and how can they improve the overall results and their reliability;
4. to start method evaluation at the reference sites and how the methods fit into the general MODELPROBE approach;
5. to start the development of the overall approach in terms of guidelines and method evaluation.
The general objectives for the second period were to run the project and to organise the communication strategies and interaction for the various disciplines working together in the project.
The objectives for this reporting period are:
1. to validate the various methods, in particular the new geophysical ones;
2. to apply the methods either non-invasively or combined with direct push techniques;
3. to apply spatio-temporal statistical methods to the data of the various methods and to show how they improve the overall results and their reliability;
4. to continue method evaluation at the reference sites and to adjust the methods to the general MODELPROBE approach;
5. to develop the overall approach in terms of guidelines and method evaluation.
The general objectives for the third period were to continue the project and to organise the strategies and interaction for the various disciplines working together in the project.
The objectives for this reporting period are:
6. to continue validating the various methods;
7. to continue method evaluation and testing at the reference sites and to adjust the methods to the general MODELPROBE approach;
8. to apply spatio-temporal statistical methods to the data of the various methods and to show how they improve the overall results and their reliability;
9. to develop the overall approach in terms of the guidelines and method evaluation;
10. to organise the MODELPROBE handbook's editorial process the overall dissemination activities.
Project results:
Definition of new methods applicable at the reference sites, in comparison to conventional techniques and tools was completed.
The following techniques for site assessment are recommended by the different work packages (WPs) of the project and are based on the maturity and applicability of the methods. The details of the applicability are provided in deliverable 9.2 ('Results of field demonstration of a set of advanced techniques for general, specific and / or detailed assessment of contaminated sites; cross validation and comparison') and the report of the third period.
The methods were mostly developed or improved within the MODELPROBE project but some sound methods are also contributed from the developments of the associated project SOILCAM. All methods that can be recommended for certain tasks in the assessment of contaminated sites are documented by fact sheets (latest versions), which provide a full overview about the methods including the contact the most experienced scientists. The list is the final list for publishing within the MODELPROBE handbook.
Geophysical methods (WPs 1-3)
1. Self-potential (SP)
2. Electrical impedance tomography (EIT) / Spectral induced polarisation (SIP)
3. Electromagnetic induction mapping (terrain conductivity)
4. Ground penetrating radar (GPR)
5. Radio magnetotelluric (RMT; SOILCAM)
6. Geophysical data fusion.
Minimally invasive methods (WPs 4 and 5)
7. Tree core monitoring
8. Direct push general introduction
9. Direct push geophysical methods
10. Direct push sampling
11. Direct push hydrostratigraphic tools
12. Direct push geotechnical methods
13. Direct push geochemical methods
Biogeochemical Methods (WP 6)
14. Compound-specific isotope analysis (CSIA)
15. Classical BACTRAP
16. Direct push BACTRAP
17. Monitoring of dechlorinating microorganisms
18. Bioassays
Laboratory methods (WP 7)
19. Cyclodextrin extraction
20. Contaminant trap
21. Equilibrium sampling
Soil water sampling methods (SOILCAM)
22. Suction cups
23. Multilevel samplers
Methods for data assimilation (WP 8)
24. Data assimilation and statistical analysis
Potential impact:
The MODELPROBE project was dedicated to the development and improvement of innovative investigation techniques and methods to be used at the assessment of contaminated sites, in particular in Europe but also worldwide. These techniques and methods focus on the detection of (hydro)geological site characteristics, contaminants and subsurface processes by geophysical and biogeochemical means. The techniques and methods covered by MODELPROBE rely on a cyclical cost and time saving overall approach for contaminated site management, which allows for short-term (on-site) decisions (MODELPROBE overall approach).
Besides introducing the MODELPROBE overall approach, the recommendations for dissemination, harmonisation and implementation, which are part of the guideline chapter of the MODELPROBE handbook, are mainly dedicated to presenting the investigation techniques and methods that have been developed and improved within the project (tool-box). The recommendations were already considered for the validation activities at the reference sites and the outcome and experience are directly incorporated into the final recommendations within the handbook. They are intended for environmental practitioners engaged in the investigation of contaminated sites including engineers as well as representatives of authorities. It addresses both:
(i) an overview on techniques and methods and how and when (at which stage of investigation) to apply them (Guideline: Part 1 of the handbook); and
(ii) detailed technical information on the techniques and methods (Manuals: Part 2 of the MODELPROBE handbook).
In the latter part there is also a section providing easy-to-understand descriptions for each technique and method (fact sheets), which can be used by site-owners or potential investors as well. The handbook is regularly published under: M. Kästner, M. Brackevelt, G. Döberl, G. Cassiani, M. Petrangeli Papini, C. Leven-Pfister and D. van Ree (editors.). Model-driven soil probing, site assessment and evaluation - Guidance on technologies. ISBN 978-88-95814-72-8. Printed in Italy by Centro Stampa Università, Sapienza University of Rome and can be ordered via the project homepage. For enabling the users to consider the details, an e-learning course was also developed and is provided by a DVD within the handbook or at http://modelprobe.dissemination.org.
The detailed analyses of administrative and legal constraints as well as the recommendations for dissemination, harmonisation, and implementation of the MODELPROBE approach and toolbox are presented in in the guideline of the handbook. A brief guidance of the practical use for all potential users (authorities, stakeholders, and consultants/engieers) is presented below:
1. A brief guidance to the practical use of the techniques covered by MODELPROBE
How to integrate MODELPROBE within an overall site investigation frameworks
1.1. MODELPROBE within a tiered investigation approach
Since contaminated land management is to a large extent a regulator- and authority-driven process, many countries have implemented more or less complex and extensive schemes and procedures to support decision making in this field. Most of these schemes or procedures are based on a tiered approach in order to identify contaminated sites and the impacts originating from them in a systematic way.
1.2. Tier 1: Sketching an initial conceptual site model (level 1)
Tier 1 consists of preliminary investigations including desktop-based investigations focusing on the question whether a pollution of the environment is likely. To figure out the main environmental issues of a site, typical information and data needed at this tier include:
- type of industrial or commercial activities on the site (historically and recently);
- information regarding possible impacts on the environment (e.g. operation period of relevant activities, accidents, extent of (soil or groundwater threatening) activities, i.e. type and size of technical installations, number of employees etc.)
- basic information on geology and hydrogeology: depending on availability on local and on regional scale and contaminants: which contaminants are likely?
First field investigations typically are intended to give a rough overview on geology and hydrogeology. If at all, sampling takes place at e.g. existing wells or by cost-effective screening methods.
Contribution of the techniques covered by MODELPROBE at Tier 1
Although MODELPROBE techniques are mostly focused on Tier 2 and Tier 3, some of them might be considerably useful at this tier in order to screen the site surface-based for potential geological anomalies or pollutants with geophysical techniques and / or tree core monitoring and to get a first rough insight into subsoil conditions with classical direct push applications. Besides, this investigation step is crucial to all further investigations since the initial CSM (level 1) developed at this tier is the (only) information basis when it comes to extended field investigations at Tier 2.
1.3. Tier 2: Creating a conceptual site model (level 2) as a basis for risk assessments
Based on the initial site model, tier 2 is dedicated to detailed site investigations in order to characterise the contaminants' source(s), their potential migration and their potential impacts. The latter includes environmental media such as ambient air, soil, or groundwater as well as receptors such as humans, animals, plants or ecosystems, which are or might be affected by the contamination.
The investigation results at this stage typically lead to a CSM (level 2), serving as a basis for the risk assessment to be followed. Based on the risk assessment, it has to be decided whether risks to humans or the environment originating from a specific site are acceptable or whether there is a need for measures to lower the risk, e.g. by remediation measures or use restrictions.
At this tier, the questions to be addressed in particular largely depend on the type of risk assessment to be applied, but typically include:
- type of contamination;
- extent of contamination (e.g. delineation of contaminants' source and plume or contaminants' distribution);
- mobility, transport and degradation of contaminants;
- impact on affected media or receptors.
Besides further desktop-based historical investigations, among typical tier 2 field and laboratory investigations are:
- geological, hydrological and hydrogeological investigations; % - sampling and analysis of air / gas, soil and (ground)water at the site and determination of biogeochemical conditions;
- laboratory tests regarding availability of contaminants (leaching tests, column tests);
- toxicity assessment.
Contribution of MODELPROBE at tier 2
The MODELPROBE approach and its techniques and methods are tailored to answer the questions addressed at this tier. By its cyclical approach, in many cases allowing for short-term feedback loops including on-site data assessment and decision making, the CSM can be updated regularly with structured data and information in order to get an appropriate basis for the next investigation steps. As mentioned before, the application of MODELPROBE's non-invasive or low-invasive investigation techniques in particular for screening purposes helps to support or substitute classical investigation techniques such as drilling, sampling and laboratory analyses in a time and cost saving way.
Particularly, the interaction of geophysical and classical direct push techniques will contribute significantly to a complete geological, hydrogeological and contaminant related picture of the subsoil. This is also crucial to the appropriate planning of expensive drilling campaigns.
Geotechnical and chemical data from direct push investigations (including sampling of soil, gas and groundwater) should be used to calibrate the results of geophysical measurements in order to separate geological from chemical signals. After calibrating, geophysics consequently serves to fill inevitable spatial gaps left by direct push investigations. On the other hand, these methods may be applied for initial screening to identify anomalies at the respective site.
- Tree core monitoring may be performed for initial screening or to complement investigations focussing on the delineation of plumes in shallow groundwater (e.g. in order to optimise the positioning of further drillings, direct push investigations or monitoring wells).
- Conventional pumping tests to assess the hydraulic conductivity can be supported (or partially substituted) by hydraulic direct push (hydraulic head measurements) investigations.
- Compound specific isotope analysis (CSIA) can be used to detect and quantify in situ microbial degradation of organic contaminants or to map degradation pathways in plumes.
- Assessment of impacts on ecosystems can be based on bioassays as indicators for ecotoxicity.
- For assessing the bioavailable fraction of persistent contaminants like PAH, innovative laboratory methods such as contaminant trap, HPCD-shake extraction technique or equilibrium sampling can be performed to support conventional techniques like leaching or column tests.
- To support an overall assessment of results and allow for an appropriate data management, methods of spatial statistics, data comparison and data assimilation should be applied from the very beginning of the investigation campaign.
1.4. Tier 3: Refining the conceptual site model (level 3) when it comes to remediation
Tier 3 is only relevant to sites where (remediation) measures have to be performed to lower the risks originating from a site. The main questions to be addressed at this tier are the following:
- Which remediation goals / targets have to be met?
- Which remediation technology will meet the goals / targets?
Generally, the remediation goals depend on technical, environmental and economic feasibility, i.e.:
- the goal should be environmentally sound;
- a technology to meet the goal should be available; and
- the corresponding costs can be covered.
Based on the CSM, investigations at tier 3 ideally lead to a refined CSM (level 3) and mostly address the following two issues:
- refinement of the CSM, i.e. assessing quality and quantity of the contamination more precisely in order to be able to pre-select appropriate remediation technologies (see above); generally, the same investigation techniques are used as at tier 2;
- investigations specific to pre-selected remediation technologies (e.g. specific hydraulic and geotechnical investigations or biogeochemical investigations to assess or to proof the effectiveness of natural attenuation processes).
During and after remediating a site, the effectiveness of remediation measures has to be monitored and assessed (final risk assessment) at tier 3. Monitoring includes sampling and analysis of air / gas, soil and (ground)water on the site and its surroundings, but also maintenance of technical installations. To ensure comparability, assessing the effectiveness of remediation measures should be performed in a similar way as the risk assessment prior to the remediation measures.
Contribution of MODELPROBE at tier 3
As with tier 2, the MODELPROBE approach as well as its techniques and methods are dedicated to be applied extensively at tier 3. Again, the cyclical approach will allow for a continuous update of the CSM, resulting in its final version - a refined CSM (level 3).
In addition to their use at tier 2, the techniques and methods covered by MODELPROBE can be performed at tier 3 as follows:
- A combination of geophysical and all kinds of direct push techniques can be performed to refine the CSM - e.g. to get detailed geotechnical or hydrological information necessary for the pre-selection or the planning of remediation measures. After an appropriate calibration, geophysical techniques may be used as cost-effective (long-term) monitoring tools (see tier 4). This applies for direct push investigations as well: They can be used either for assessing the effectiveness of remediation measures in-situ or for sampling purposes.
- CSIA contributes to the assessment of the effectiveness of on-going natural attenuation processes or of remediation measures to stimulate (bio)degradation (e.g. all kinds of enhanced natural attenuation).
- BACTRAPs, either installed in groundwater wells or used as a direct push probe, are applied to evaluate biological degradation potentials or remediation options under various redox conditions (pre-selection of remediation measures).
- If dechlorinating processes need to be assessed, fluorescent in-situ hybridisation techniques (FISH and CARD-FISH) should be applied for the quantification of dechlorinating microorganisms, which directly corresponds to the effectiveness of dechlorinating processes. The assessment of the distribution of key degrading bacteria in the aquifer can be used to assess whether conditions for natural attenuation are favourable.
- Bioassays are used to complement chemical data when assessing the effectiveness of remediation measures or monitoring.
- Laboratory methods such as contaminant trap, HPCD-shake extraction technique or equilibrium sampling can be used to assess the effectiveness of measures to reduce the bioavailable fraction of contaminants.
1.5. Tier 4: Post-remediation monitoring and maintenance
Besides classical maintenance works, long-term monitoring at tier 4 should ensure long-term effectiveness of after-care measures and, especially, of long-lasting safeguarding measures or enhanced / monitored natural attenuation.
Contribution of MODELPROBE at tier 4
Basically, all techniques proposed for monitoring purposes at tier 3 can be applied at tier 4 as well. Special attention should be given to geophysical and biogeochemical techniques, which, once calibrated or proved to be effective at the tiers before, may have a high potential to substitute classical techniques for long-term monitoring purposes at tier 4.
List of websites: MODELPROBE website: http://www.modelprobe.eu
Advanced geophysical site characterisation techniques combined with new types of vegetation analysis were developed. Based on these non-invasive surveys, the extension of sources, contamination levels (THP, BTEX, PAH, CHC, explosives, and heavy metals) and soil heterogeneities can be localised first. Hot spots will then be investigated by new direct push probing systems integrated with geophysical and hydrogeological methods and combined with chemical and isotopic contaminant analysis for source localisation and identification (environmental forensics). The actually occurring bioprocesses, such as contaminant degradation or sorption and mobilisation processes, are assessed using biosensors, in situ microcosms and stable isotope and biomarker analysis. These new techniques and tools were evaluated against best practice of conventional methods and the results are documented in the MODELPROBE handbook in addition to more than 45 scientific publications (ISI).
The MODELPROBE project provided the opportunity to test, optimise and demonstrate the proposed approach at fully equipped and characterised European brownfield reference sites in Germany, Italy, Norway and the Czech Republic. Integrated statistical analysis and modelling at different stages, the step by step approach resulted in an improved view of soil and subsurface contamination and provides a sound basis for a cost-effective risk assessment and decision in the choice of the most appropriate sustainable remediation strategy.
Project context and objectives:
Conventional techniques for site characterisation and management are mostly made of unrelated tasks (site history assessment, drilling, sampling, chemical / toxicological analysis, consulting, risk assessment, and remediation action). This approach is highly expensive, extremely time consuming and currently is not directed to supporting the decision making at an early project stage. Present techniques are not suitable to trigger effective assessment, management and remediation actions and therefore, need integration. In particular, they are mostly not compatible with a future soil Framework Directive planned to follow up the present soil thematic strategy of the European Commission (EC).
In particular, current conventional site assessment techniques do not cover screening of potentially contaminated sites, source analysis regarding environmental forensics and most methods are not suitable to be extended towards remediation monitoring. In addition, the present state of the art in geological site assessment requires generally some kind of drilling with the corresponding costs and effort resulting in low area coverage. Therefore, innovative flexible and minimal invasive types of geo-sampling were required at the beginning of the project.
As a consequence, improved technologies and tools for step by step site characterisation with smart feedback loops are necessary and were developed in between by the MODELPROBE project and also outside. These new techiques support the upcoming soil Framework Directive planned by the EC. Within the framework of the MODELPROBE project, a combination of advanced geophysical site characterisation techniques with new types of low-cost vegetation analysis have been developed. Based on these non-invasive surveys, the extension of sources, contamination levels and soil heterogeneities can be localised first. Hot spots will then be investigated by novel direct push probing systems including geophysical and hydrogeological methods combined with chemical and isotopic contaminant analysis for source localisation and identification (environmental forensics). Bioprocesses such as bioavailability, contaminant degradation or sorption or remobilisation processes can now be assessed by biosensors, in situ microcosms, stable isotope and biomarker analysis.
Novel techniques and tools, however, always need to be evaluated against best practice of conventional methods. Therefore, the new tools were applied in parallel at fully equipped and characterised European reference sites available for the MODELPROBE consortium (Trecate and Rho, Italy; Zeitz in Germany; Mimon / SAP, Czech Republic; Moeringa, Norway; for details see MODELPROBE homepage: http://www.MODELPROBE.eu online). These sites have been equipped in previous projects or by other national sources (European Union (EU)-funded projects: BIOTOOL, WELCOME, BIOISOTOPE; German BMBF-projects: RETZINA, SAFIRA, and several others). Integrated statistical analysis and modelling at different stages of the step by step approach resulted in an improved view of soil and subsurface contamination and provided the sound basis for risk assessment decision. The developed tools are now provided as guidelines and operation manuals and are available to industry, small and medium-sized enterprises (SMEs), consultants, and authorities for application within the framework of the MODELPROBE handbook.
Objectives:
A step by step characterisation approach for contaminated sites comprise an inherent feedback loop strategy that allows referring back at each stage to the results of previous stages. This approach helps minimising the effort and providing sufficient information necessary for a decision at each point. This approach requires operation manuals of the specific analytical tools that are related to each other and, what is more important, an integrated statistical analysis of the geological, geophysical, chemical, biotic and ecotoxicologial data aiming at a three-dimensional (3D) modelling of the contamination at a site derived from a minimal data set. This concept provides a very high cost / efficiency ratio for site assessment.
Since new methods need to be validated properly before being considered resistant to a legal scrutiny, the developed techniques and combined tools in the MODELPROBE project are related to conventional assessment techniques. However, the effort required by such comparison would require a separate project. Therefore, the MODELPROBE approach was tested at fully equipped European reference sites that were characterised by the necessary suite of drillings, chemical inventory and hydrological modelling, and subjected to continuous monitoring or even operating remediation measures. In addition, the implementation of new approaches always required training of users, consultants, decision makers, authorities, and even of environmental lawyers. This requirement was also an inherent part of the project. General objectives of the project were the following:
- To develop and improve a set of new, relatively simple-to-use and minimally or non-invasive methods for the assessment of contaminated soils in the framework of the soil thematic strategy. This set of methods should provide a toolbox for future application in the planned soil Framework Directive for the general purpose of contaminated site characterisation and monitoring of remediation progress. The following issues are addressed:
- general site characterisation and (hydro-)geology (vegetation analysis, geophysics, and direct push);
- analysis of biogeochemical conditions (direct push with new approaches);
- analysis of contaminants (plant based primary assessment or monitoring, direct push with new approaches, isotope analysis);
- assessment of ecotoxicology (passive samplers, toxicity testing, effect based analysis);
- analysis of sources (isotope analysis with environmental forensics);
- assessment of microbial degradation activity and contaminant bioavailability (compound specific stable isotope fractionation analysis, in situ microcosms, e.g. BACTRAP and fuel cell meter).
- To evaluate the methods against conventional technologies at fully characterised sites (Zeitz, Germany; SAP, Czech Republic; Trecate and Rho, Italy).
- To evaluate the methods as appropriate information sources for long term monitoring purposes and to assist Monitored Natural Attenuation measures.
- To provide additional modelling tools for integrative assessment.
- To provide guidelines for applying the new tools in order to instruct decision makers, consultants and users with the chances and limitation of the new tools.
Transformation of the general objectives into specific ones of the reporting periods:
The general objectives for the first period were to implement the project and to find the appropriate language and communication strategies for the various disciplines working together in the project.
The objectives for the first reporting period are:
1. to evaluate the validity, chances and limitations of the various methods, in particular the new geophysical ones;
2. to check how the methods can be applied non-invasively or be combined with direct push techniques;
3. to evaluate how spatio-temporal statistical methods can be applied to the data of the various methods and how can they improve the overall results and their reliability;
4. to start method evaluation at the reference sites and how the methods fit into the general MODELPROBE approach;
5. to start the development of the overall approach in terms of guidelines and method evaluation.
The general objectives for the second period were to run the project and to organise the communication strategies and interaction for the various disciplines working together in the project.
The objectives for this reporting period are:
1. to validate the various methods, in particular the new geophysical ones;
2. to apply the methods either non-invasively or combined with direct push techniques;
3. to apply spatio-temporal statistical methods to the data of the various methods and to show how they improve the overall results and their reliability;
4. to continue method evaluation at the reference sites and to adjust the methods to the general MODELPROBE approach;
5. to develop the overall approach in terms of guidelines and method evaluation.
The general objectives for the third period were to continue the project and to organise the strategies and interaction for the various disciplines working together in the project.
The objectives for this reporting period are:
6. to continue validating the various methods;
7. to continue method evaluation and testing at the reference sites and to adjust the methods to the general MODELPROBE approach;
8. to apply spatio-temporal statistical methods to the data of the various methods and to show how they improve the overall results and their reliability;
9. to develop the overall approach in terms of the guidelines and method evaluation;
10. to organise the MODELPROBE handbook's editorial process the overall dissemination activities.
Project results:
Definition of new methods applicable at the reference sites, in comparison to conventional techniques and tools was completed.
The following techniques for site assessment are recommended by the different work packages (WPs) of the project and are based on the maturity and applicability of the methods. The details of the applicability are provided in deliverable 9.2 ('Results of field demonstration of a set of advanced techniques for general, specific and / or detailed assessment of contaminated sites; cross validation and comparison') and the report of the third period.
The methods were mostly developed or improved within the MODELPROBE project but some sound methods are also contributed from the developments of the associated project SOILCAM. All methods that can be recommended for certain tasks in the assessment of contaminated sites are documented by fact sheets (latest versions), which provide a full overview about the methods including the contact the most experienced scientists. The list is the final list for publishing within the MODELPROBE handbook.
Geophysical methods (WPs 1-3)
1. Self-potential (SP)
2. Electrical impedance tomography (EIT) / Spectral induced polarisation (SIP)
3. Electromagnetic induction mapping (terrain conductivity)
4. Ground penetrating radar (GPR)
5. Radio magnetotelluric (RMT; SOILCAM)
6. Geophysical data fusion.
Minimally invasive methods (WPs 4 and 5)
7. Tree core monitoring
8. Direct push general introduction
9. Direct push geophysical methods
10. Direct push sampling
11. Direct push hydrostratigraphic tools
12. Direct push geotechnical methods
13. Direct push geochemical methods
Biogeochemical Methods (WP 6)
14. Compound-specific isotope analysis (CSIA)
15. Classical BACTRAP
16. Direct push BACTRAP
17. Monitoring of dechlorinating microorganisms
18. Bioassays
Laboratory methods (WP 7)
19. Cyclodextrin extraction
20. Contaminant trap
21. Equilibrium sampling
Soil water sampling methods (SOILCAM)
22. Suction cups
23. Multilevel samplers
Methods for data assimilation (WP 8)
24. Data assimilation and statistical analysis
Potential impact:
The MODELPROBE project was dedicated to the development and improvement of innovative investigation techniques and methods to be used at the assessment of contaminated sites, in particular in Europe but also worldwide. These techniques and methods focus on the detection of (hydro)geological site characteristics, contaminants and subsurface processes by geophysical and biogeochemical means. The techniques and methods covered by MODELPROBE rely on a cyclical cost and time saving overall approach for contaminated site management, which allows for short-term (on-site) decisions (MODELPROBE overall approach).
Besides introducing the MODELPROBE overall approach, the recommendations for dissemination, harmonisation and implementation, which are part of the guideline chapter of the MODELPROBE handbook, are mainly dedicated to presenting the investigation techniques and methods that have been developed and improved within the project (tool-box). The recommendations were already considered for the validation activities at the reference sites and the outcome and experience are directly incorporated into the final recommendations within the handbook. They are intended for environmental practitioners engaged in the investigation of contaminated sites including engineers as well as representatives of authorities. It addresses both:
(i) an overview on techniques and methods and how and when (at which stage of investigation) to apply them (Guideline: Part 1 of the handbook); and
(ii) detailed technical information on the techniques and methods (Manuals: Part 2 of the MODELPROBE handbook).
In the latter part there is also a section providing easy-to-understand descriptions for each technique and method (fact sheets), which can be used by site-owners or potential investors as well. The handbook is regularly published under: M. Kästner, M. Brackevelt, G. Döberl, G. Cassiani, M. Petrangeli Papini, C. Leven-Pfister and D. van Ree (editors.). Model-driven soil probing, site assessment and evaluation - Guidance on technologies. ISBN 978-88-95814-72-8. Printed in Italy by Centro Stampa Università, Sapienza University of Rome and can be ordered via the project homepage. For enabling the users to consider the details, an e-learning course was also developed and is provided by a DVD within the handbook or at http://modelprobe.dissemination.org.
The detailed analyses of administrative and legal constraints as well as the recommendations for dissemination, harmonisation, and implementation of the MODELPROBE approach and toolbox are presented in in the guideline of the handbook. A brief guidance of the practical use for all potential users (authorities, stakeholders, and consultants/engieers) is presented below:
1. A brief guidance to the practical use of the techniques covered by MODELPROBE
How to integrate MODELPROBE within an overall site investigation frameworks
1.1. MODELPROBE within a tiered investigation approach
Since contaminated land management is to a large extent a regulator- and authority-driven process, many countries have implemented more or less complex and extensive schemes and procedures to support decision making in this field. Most of these schemes or procedures are based on a tiered approach in order to identify contaminated sites and the impacts originating from them in a systematic way.
1.2. Tier 1: Sketching an initial conceptual site model (level 1)
Tier 1 consists of preliminary investigations including desktop-based investigations focusing on the question whether a pollution of the environment is likely. To figure out the main environmental issues of a site, typical information and data needed at this tier include:
- type of industrial or commercial activities on the site (historically and recently);
- information regarding possible impacts on the environment (e.g. operation period of relevant activities, accidents, extent of (soil or groundwater threatening) activities, i.e. type and size of technical installations, number of employees etc.)
- basic information on geology and hydrogeology: depending on availability on local and on regional scale and contaminants: which contaminants are likely?
First field investigations typically are intended to give a rough overview on geology and hydrogeology. If at all, sampling takes place at e.g. existing wells or by cost-effective screening methods.
Contribution of the techniques covered by MODELPROBE at Tier 1
Although MODELPROBE techniques are mostly focused on Tier 2 and Tier 3, some of them might be considerably useful at this tier in order to screen the site surface-based for potential geological anomalies or pollutants with geophysical techniques and / or tree core monitoring and to get a first rough insight into subsoil conditions with classical direct push applications. Besides, this investigation step is crucial to all further investigations since the initial CSM (level 1) developed at this tier is the (only) information basis when it comes to extended field investigations at Tier 2.
1.3. Tier 2: Creating a conceptual site model (level 2) as a basis for risk assessments
Based on the initial site model, tier 2 is dedicated to detailed site investigations in order to characterise the contaminants' source(s), their potential migration and their potential impacts. The latter includes environmental media such as ambient air, soil, or groundwater as well as receptors such as humans, animals, plants or ecosystems, which are or might be affected by the contamination.
The investigation results at this stage typically lead to a CSM (level 2), serving as a basis for the risk assessment to be followed. Based on the risk assessment, it has to be decided whether risks to humans or the environment originating from a specific site are acceptable or whether there is a need for measures to lower the risk, e.g. by remediation measures or use restrictions.
At this tier, the questions to be addressed in particular largely depend on the type of risk assessment to be applied, but typically include:
- type of contamination;
- extent of contamination (e.g. delineation of contaminants' source and plume or contaminants' distribution);
- mobility, transport and degradation of contaminants;
- impact on affected media or receptors.
Besides further desktop-based historical investigations, among typical tier 2 field and laboratory investigations are:
- geological, hydrological and hydrogeological investigations; % - sampling and analysis of air / gas, soil and (ground)water at the site and determination of biogeochemical conditions;
- laboratory tests regarding availability of contaminants (leaching tests, column tests);
- toxicity assessment.
Contribution of MODELPROBE at tier 2
The MODELPROBE approach and its techniques and methods are tailored to answer the questions addressed at this tier. By its cyclical approach, in many cases allowing for short-term feedback loops including on-site data assessment and decision making, the CSM can be updated regularly with structured data and information in order to get an appropriate basis for the next investigation steps. As mentioned before, the application of MODELPROBE's non-invasive or low-invasive investigation techniques in particular for screening purposes helps to support or substitute classical investigation techniques such as drilling, sampling and laboratory analyses in a time and cost saving way.
Particularly, the interaction of geophysical and classical direct push techniques will contribute significantly to a complete geological, hydrogeological and contaminant related picture of the subsoil. This is also crucial to the appropriate planning of expensive drilling campaigns.
Geotechnical and chemical data from direct push investigations (including sampling of soil, gas and groundwater) should be used to calibrate the results of geophysical measurements in order to separate geological from chemical signals. After calibrating, geophysics consequently serves to fill inevitable spatial gaps left by direct push investigations. On the other hand, these methods may be applied for initial screening to identify anomalies at the respective site.
- Tree core monitoring may be performed for initial screening or to complement investigations focussing on the delineation of plumes in shallow groundwater (e.g. in order to optimise the positioning of further drillings, direct push investigations or monitoring wells).
- Conventional pumping tests to assess the hydraulic conductivity can be supported (or partially substituted) by hydraulic direct push (hydraulic head measurements) investigations.
- Compound specific isotope analysis (CSIA) can be used to detect and quantify in situ microbial degradation of organic contaminants or to map degradation pathways in plumes.
- Assessment of impacts on ecosystems can be based on bioassays as indicators for ecotoxicity.
- For assessing the bioavailable fraction of persistent contaminants like PAH, innovative laboratory methods such as contaminant trap, HPCD-shake extraction technique or equilibrium sampling can be performed to support conventional techniques like leaching or column tests.
- To support an overall assessment of results and allow for an appropriate data management, methods of spatial statistics, data comparison and data assimilation should be applied from the very beginning of the investigation campaign.
1.4. Tier 3: Refining the conceptual site model (level 3) when it comes to remediation
Tier 3 is only relevant to sites where (remediation) measures have to be performed to lower the risks originating from a site. The main questions to be addressed at this tier are the following:
- Which remediation goals / targets have to be met?
- Which remediation technology will meet the goals / targets?
Generally, the remediation goals depend on technical, environmental and economic feasibility, i.e.:
- the goal should be environmentally sound;
- a technology to meet the goal should be available; and
- the corresponding costs can be covered.
Based on the CSM, investigations at tier 3 ideally lead to a refined CSM (level 3) and mostly address the following two issues:
- refinement of the CSM, i.e. assessing quality and quantity of the contamination more precisely in order to be able to pre-select appropriate remediation technologies (see above); generally, the same investigation techniques are used as at tier 2;
- investigations specific to pre-selected remediation technologies (e.g. specific hydraulic and geotechnical investigations or biogeochemical investigations to assess or to proof the effectiveness of natural attenuation processes).
During and after remediating a site, the effectiveness of remediation measures has to be monitored and assessed (final risk assessment) at tier 3. Monitoring includes sampling and analysis of air / gas, soil and (ground)water on the site and its surroundings, but also maintenance of technical installations. To ensure comparability, assessing the effectiveness of remediation measures should be performed in a similar way as the risk assessment prior to the remediation measures.
Contribution of MODELPROBE at tier 3
As with tier 2, the MODELPROBE approach as well as its techniques and methods are dedicated to be applied extensively at tier 3. Again, the cyclical approach will allow for a continuous update of the CSM, resulting in its final version - a refined CSM (level 3).
In addition to their use at tier 2, the techniques and methods covered by MODELPROBE can be performed at tier 3 as follows:
- A combination of geophysical and all kinds of direct push techniques can be performed to refine the CSM - e.g. to get detailed geotechnical or hydrological information necessary for the pre-selection or the planning of remediation measures. After an appropriate calibration, geophysical techniques may be used as cost-effective (long-term) monitoring tools (see tier 4). This applies for direct push investigations as well: They can be used either for assessing the effectiveness of remediation measures in-situ or for sampling purposes.
- CSIA contributes to the assessment of the effectiveness of on-going natural attenuation processes or of remediation measures to stimulate (bio)degradation (e.g. all kinds of enhanced natural attenuation).
- BACTRAPs, either installed in groundwater wells or used as a direct push probe, are applied to evaluate biological degradation potentials or remediation options under various redox conditions (pre-selection of remediation measures).
- If dechlorinating processes need to be assessed, fluorescent in-situ hybridisation techniques (FISH and CARD-FISH) should be applied for the quantification of dechlorinating microorganisms, which directly corresponds to the effectiveness of dechlorinating processes. The assessment of the distribution of key degrading bacteria in the aquifer can be used to assess whether conditions for natural attenuation are favourable.
- Bioassays are used to complement chemical data when assessing the effectiveness of remediation measures or monitoring.
- Laboratory methods such as contaminant trap, HPCD-shake extraction technique or equilibrium sampling can be used to assess the effectiveness of measures to reduce the bioavailable fraction of contaminants.
1.5. Tier 4: Post-remediation monitoring and maintenance
Besides classical maintenance works, long-term monitoring at tier 4 should ensure long-term effectiveness of after-care measures and, especially, of long-lasting safeguarding measures or enhanced / monitored natural attenuation.
Contribution of MODELPROBE at tier 4
Basically, all techniques proposed for monitoring purposes at tier 3 can be applied at tier 4 as well. Special attention should be given to geophysical and biogeochemical techniques, which, once calibrated or proved to be effective at the tiers before, may have a high potential to substitute classical techniques for long-term monitoring purposes at tier 4.
List of websites: MODELPROBE website: http://www.modelprobe.eu
