Database/Expert system functions
Outline of the database/expert system for environmental impact assessment based on release as derived from leaching tests
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Evaluation Guidance - problem definition, selection of characterisation needs and methods, detailed methodologies; provision of existing information characteristics and behaviour of materials similar to that in question.
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Laboratory Guidance - lysimeter and field data collection including experimental design and quality control considerations; existing information from similar pilot and field evaluations.
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Data Management - standardized formatting and graphical presentation, including consistency and quality control checking.
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Data Evaluation - parameter derivation and comparative data analysis.
a. pH and redox dependency of aqueous concentrations (cations, anions, DOC, ionic strength), geochemical speciation, acid/base neutralisation capacity, leaching potential (availability) from batch testing.
b. Release of contaminants as a function of time for granular and monolithic materials from sequential data sets (liquid to solid ratio or time dependency from monolithic or compacted granular tank leaching tests, column testing, lysimeter testing), including geochemical speciation and mass transfer parameter estimation.
c. Quality control based on the use of simplified testing in comparison with earlier more detailed characterisation of the same or comparable materials.
d. Statistical evaluation of leaching data (pH stat, percolation tests, monolith leach test)
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Source Term Descriptions - estimate constituent release as a function of time for default or user-defined application or management scenarios. This would include selection of appropriate source term models, evaluation of the effects of potential external influences (e.g. mixing with other materials, carbonation, oxidation, reduction, and acidification) and uncertainty analysis.
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Impact Evaluation - potential impacts on soil, groundwater or surface water and risk estimation, including the application of default or user-defined transport and fate scenarios.
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Decision Algorithms - for comparison of evaluation results and decision-making based on regulatory criteria from different jurisdictions; recommendations on reduced-testing quality control programs; recommendations on approaches to reduce constituent release and environmental impacts.
The software for the database/expert system includes data conversion tools based on MS Excel and data import tools for the Access database. In this way a user may insert his own data into LeachXS and obtain the desired answer or result. If the user is interested in information on a specific type of material but does not have any data on that material, typical default data on more than a 100 different materials are available and may be drawn from the database.
The following activities are associated with LeachXS are envisaged:
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Release of LeachXS to users for an annual licence fee (possibly in more than one version, depending on the purpose and the costumers' needs)
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Training courses on the use of LeachXS; and
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Performance of research projects and expert consultation by ECN, VU and DHI using LeachXS.
The released versions of LeachXS contains publicly available data on a wide range of different materials.
Versions of LeachXS for use on individual personal computers, through server-based licence use, and full server-based versions for remote system use are envisioned.