The NORISC decision support system (DSS) basically guides the development of a methodology for investigating and assessing a contaminated site, and, in particular, for determining the contaminant occurrence in soil and groundwater, as well as the risks involved and the potential site reuse.
As far as environmental pollution and, more specifically, contamination of soil and groundwater with hazardous substances is concerned, guideline and reference concentration values for different kinds of contamination limits were reviewed, taking into account the relevant national legislations in the European Union, in accession countries and the USA.
National standards relating to the investigation and management of contaminated sites were considered, too. Furthermore, feedback from the various stakeholders involved was evaluated in order to consider the real expectations for the improvement of site characterisation and assessment.

To establish an evaluation tool for selecting the appropriate site investigation methods, a European inventory of contamination profiles was compiled on the basis of existing data sets and surveys. In addition, a register of investigation methodologies was set up that contains their technical and efficacy descriptions.

The NORISC project has developed the following data sets and input tables for the evaluation matrix to select relevant investigation methods
Legislation on contaminated site management and user requirements
  • Stakeholders' requirements analysed during the case studies Contamination guideline and limit values
    		•
    Contaminated site characteristics in an urban environment
  • Case studies in European countries and in the US
  • Contamination profiles
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    Register of investigation methodologies
  • Hydro-geological site characterisation rules, restrictions on testing
  • Register of geochemical analysis
  • Register of geophysical investigation methods
  • Register of biological investigation methods
  • Register of geochemical and hydrogeological sampling methods
    		•

    Regulations and stakeholders' requirements

    The main requests of stakeholders were compiled using questionnaires sent to public authorities, land users and owners, potential investors, as well as to private companies dealing with contaminated site management. According to the outcome of the interviews, the public stakeholders mainly require fixed contamination levels of the site depending on the future land use. Therefore, a guideline value set concerning the levels of pollution and risk has been established.

    STAKEHOLDERS SITE CHARACTERISATION PHASE REQUEST



    Public authorities


    Land users and owners


    Investors


    Site redevelopment companies
    		 Planning Secure statement of investigation costs
    Quality of site investigation results to be assured
    Integration of planned use into clean up action planning
    Security concerning unknown contaminants
    Need for integration of investigation methods
    Need for a preliminary impact assessment
    Importance of detecting contaminants in groundwater and not only in soil
    Site investigation Improvement of flow of information between all participants
    Time saving
    Full-coverage, spatial results
    One team of technicians with different areas of expertise
    Low cost investigation techniques for small size contaminated sites
    Data management Improvement of visualisation (GIS)
    GIS needed in case of mega sites
    Importance of identifying the linkage between soil and groundwater contamination
    Risk assessment Compare possibilities and restrictions
    Remediation costs to be included
    Risk visualisation
    Tiered approach needed
    Land use options
    Remedial scenarios
    Improve the objectivity of risk assessment
    Agricultural reuse of brownfields with specific target values for clean up

    Contamination profiles

    A representative inventory of contamination profiles was achieved on a European scale. National and regional public authorities and city offices, as well as site owners and users provided information on typical polluted sites in urban industrial areas all over Europe

    Studied conditions Examined sites Outcome
    Type of pollutant
    Time-length of pollution
    Contamination source and corresponding activity
    Geology and hydrogeology
    Actions for contaminated site management - investigation and clean up duration and cost
    Reuse and site revitalisation     		Total of 119 of contaminated sites from 10 European countries and 198 sites from the US 32 typical contaminating industrial activities and 14 "other" activities
    General hydrogeological conditions
    Case studies on contaminated site management from different countries

    Each activity that "causes pollution" was associated with a specific contamination profile that lists the expected polluting elements and compounds. This means that, on the basis of the known activity conducted at the site, the type of contaminants that will probably occur can be identified in order to determine the investigation strategy and the investigation methods

    Source of pollution Cd Hg Cu Pb Hg Ni Zn As
    Airports X X X X
    Animal and animal product processing works X X X
    Asbestos manufacturing works X X X
    Ceramics, cement and asphalt manufacturing works X X X X X X X X
    Charcoal works X X X X X X X
    Chemical works, coatings (paints and printing inks) manufacturing works X X X X X X
    Chemical works, cosmetics and toiletries manufacturing works X X
    Chemical works, disinfectant manufacturing works X X X X X

    In addition, the most relevant hydrogeological and geological parameters were identified. These parameters are necessary for characterising the spatial distribution of pollutants in soil and groundwater, as well as the potential hydrogeological exposure pathways. The methods for the necessary geological and hydrogeological site characteristics including restrictions as to their determination are summarised in the "Preliminary site analysis characterisation rules", which is an integral part of the developed NORISC investigation strategy.
    The geological-hydrogeological characteristics are grouped together to form the geological-hydrogeological (GH) profile of the site. The GH profile is categorised according to 6 aspects:

    TOPOGRAPHY
    OUTCROPPING LITHOLOGY
    GEOLOGICAL STRUCTURE
    GENERAL HYDROGEOLOGY
    HYDROGEOLOGICAL RISK ASSESSMENT
    RESTRICTIONS TO HG TESTING

    Investigation methods

    The collection and evaluation of all existing sampling, on-site and laboratory analytical, geophysical screening and biochemical test, as well as geo-statistical data processing techniques that were currently in use or at pilot stage in the partner countries was another key element in the development of the evaluation matrix for the selection of the appropriate site investigation methods. A register of all relevant methods was established.

    The investigation techniques were evaluated technically and economically, and then the most suitable methods were selected according to their practical and scientific relevance. The integration of techniques of different disciplines and the appropriateness of each particular method to improve the information obtained by other disciplines were other important issues in this assessment. Finally, the different methodologies were refined, optimised and harmonised with each other.

    Methodology Role in investigation of contaminated sites
    CHEMICAL ANALYSIS Fundamental investigations in site assessment to determine the concentration of contaminants in soil, groundwater, surface waters, air and soil gas
    On site techniques are a key element of the NORISC approach.
    GEOLOGICAL / HYDROLOGICAL For determination of site geological and hydrological characteristics related to spatial distribution of contaminants, as well as exposure pathways
    GEOPHYSICAL Geophysical methods screen subsurface physical properties of lithological units, structural discontinuities, fractures and anomalies, as well as underground cables, pipelines, tanks and foundations. On a certain level, the geophysical methodology reduces the uncertainty of site characterisation as it provides certain information on the geological structure, the pollution sources and the pools.
    BIOLOGICAL Identification of pathogens is required in some cases, while other biological methods are available for assessment of toxic effects. These methods are generally not contaminant specific, but show the actual effect of pollution by toxicity tests, biological indication, monitoring and population assessment.

    Innovative investigation techniques

    Modern on site methods have been available for several years and their effectiveness has been proven in research projects and sometimes even in practice. They are used to enhance data representativity and thereby to reduce the risk incurred by stakeholders.    		   Innovative field techniques
    CHEMICAL ANALYSIS Gas chromatography (GC)
    X-ray fluorescence (XRF)
    Photo ionisation detector (PID)
    Laser induced fluorescence (LIF)
    Laser plasma (LP)
    Photometric kits
    GEOLOGICAL / HYDROGEOLOGICAL Flow-meter
    Guelph Permeameter
    Compact Constant-Head Permeameter (Amoozemeter)
    Slug test
    GEOPHYSICAL Radiomagnetotellurics (RMT)
    Induced polarisation

    General description of investigation methods

    Geochemical, (hydro-) geological, geophysical and biological investigation methods were described in detail and the information was arranged in a compact table format. This register containing adequate investigation methods provides the required information for the developed evaluation tool and constitutes a basis for deciding on suitable combinations of site investigation methods.
    The technologies were compiled using Excel spread sheets, their parameters being suitability, cost and time. The description includes technical parameters, such as the potential information that can be obtained by using a certain method, as well as economical parameters, i.e. the costs related to the application of a method. These data are the basis for a cost and time efficiency analysis of the NORISC DSS guided site investigation methodology selected for any pollution. Where appropriate, the suitability of each method is presented as a reduced ranking system.

    The suitability including the limit of detection (LOD) of analytical methods to detect contaminants was defined, as shown in the following table.

    Method Suitability Detection limit
    Soil Water Soil gas Soil (ppm) Water (ppb) Soil gas (ppb)
    Polychlorinated Hydrocarbons (PCB)
    Gas chromatography with Flame Ionisation Detector (GC/FID) A A A 0.1-1 1-50 1-50
    Gas chromatography with Photo Ionisation Detector (GC/PID) A A A 0.1-1 1-50 1-50
    Gas chromatography with Electron Capture Detector (GC/ECD) A A A 0.1-1 1-50 1-50
    Gas chromatography with Thermal Conductivity Detector (GC/TCD) B A A 0.1-1 1-50 1-50
    GC/MS A A A 0.1-1 1-50 1-50
    GC/Ion Trap MS A A A 0.1-1 1-50 1-50
    Ion Trap MS A A A 0.1-1 1-50 1-50
    Ion Mobility Spectrometer (IMS) B B A 0.1-1 1-50 1-50
    Infrared Spectroscopy (IR) B C A 10-100 0.5-10 500-10000
    Polycylic Aromatic Hydrocarbons (PAH)
    Laser Induced Fluorescence (LIF) C A D 10-100 0.5-10
    Gas chromatography with Flame Ionisation Detector (GC/FID) A A A 0.1-1 1-50 1-50
    Gas chromatography with Photo Ionisation Detector (GC/PID) A A A 0.1-1 1-50 1-50
    Gas chromatography with Electron Capture Detector (GC/ECD) A A A 0.1-1 1-50 1-50
    Gas chromatography with Thermal Conductivity Detector (GC/TCD) B A A 0.1-1 1-50 1-50
    GC/MS A A A 0.1-1 1-50 1-50
    GC/Ion Trap MS A A A 0.1-1 1-50 1-50
    Ion Trap MS A A A 0.1-1 1-50 1-50
    Ultraviolet (UV) Fluorescence C A C 0.1-1 1-50 1-50
    Chemical Colorimetric Kits C A D 10-100 0.5-10
    Suitability is high (A), medium (B), low (C), and not suitable (D)

    Geophysical and geological/hydrogeological methods were also included in the ranking according to their suitability to determine parameters such as porosity and aquifer thickness that are related to background information and the structure of the site. Examples are given in table below.

    Geophysical methods Hydrogeological methods
    Targets/Methods
    Groundwater level D A D B B A A D D A
    Water content D C D B B D A D D C
    Hydraulic conductivity D C D C D D C B B A
    Fractures and discontinuities C C C B D D C C A C
    Effective porosity D C D B C D A D D C
    Pore water pressure D D D D D D D D D D
    Hydraulic transmissivity D D D C D D C B B A
    Foundations A B B C C A D D D D
    Pits B C B D D D D D D D
    Pipes, cables D D A D D D D D D D
    Tanks and drums D B A D D D D D D D
    Suitability is high (A), medium(B), low (C), and not suitable (D).

    The application of some methods, in particular geophysical techniques, can be hindered by certain circumstances, such as the presence of gas pipelines or electrical noise. This was also included in a table of restrictions, as some examples show:

    Method restrictions
    Magnetics B B B A B A C A B A
    DC geoelectrics B A B B B A B A B B
    Metal detectors (EM61...) C A C A B A B A C B
    Spectral IP B A B B B A C A B B
    EnviroMT C A C B B A B A C B
    Drillings B A B A B B A A A B
    Penetrometric Test A D B B B B A A A B
    Soil Analysis A A B A B B A A A B
    Infiltrometric Test A A B B B B A A A B
    Pumping Test A A B A B B A A A B
    Interference is high (D), medium (C), low (B), and very low (A).