|
Section 7: Geohazards associated with contaminated land |
1 Department of Geography, King’s College London, Strand, London WC2R 2LS, UK
2 Faculty of Environmental Studies, The Nottingham Trent University, Burton Street, Nottingham NG1 4BU, UK
3 Environmental Geochemistry Research Group, T H Huxley School of the Environment, Earth Science & Engineering, Imperial College of Science Technology and Medicine, Prince Consort Road, London SW7 2BP, UK
Spatially dependent phenomena related to heavy metal concentration in a drainage system have been evaluated using GIS methodology, so providing an indication of areas which may contain contaminated land. The geochemical distribution is used to identify the heavy metal sources. The GIS facilitates dispersion modelling defined by a digital elevation model. This can be used to delineate drainage catchments and to examine its interaction with stream sediment geochemistry. The resulting drainage basin-segment images can then be used to identify heavy metal sources. Such modelling of geochemical dispersion of metals within drainage basins allows predictions to be made as to which areas of contamination originate from which point source. The accuracy of such maps depends fundamentally on the accuracy of the dispersion model. This model includes both descriptive and deductive components concerning the influential criteria for describing the distribution of heavy metals. Each criterion is defined using an interactive discussion process that leads to the generation of a set of weighting coefficients. The integration of such criteria is achieved using fuzzy set methodology to produce images ranked according to how well they meet the selected site assessment criteria.
