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Section 1: Cleanup of contaminated land and groundwater |
Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
VOCs are the organic contaminants most widely detected in public supply wells. Due to the complexity of VOC behaviour in the subsurface and the disappointing performance of many past attempts at site remediation, it appears that for many VOC-contaminated sites complete remediation of the subsurface may be practically infeasible for the foreseeable future. The contaminants do not reside solely in the easily extractable groundwater, but also in less readily treated non-aqueous phase liquid phases, sorbed phases and dissolved phases within relatively lower permeability media. Thus complete remediation is not directed solely at ‘groundwater’, per se, but at all locations of subsurface contaminant mass. New technologies under investigation may improve prospects for complete remediation, but the problems yet to be solved are many. Thus there has been a justified shift of attention to approaches to limit the migration of plumes and thereby control the risks they pose. These migration control approaches return the attention solely to groundwater, but specifically at that passing through a selected cross-section of the subsurface. With these and other technologies under development, there may soon be a range of tools available for remediation which will match the range of remediation goals necessitated by the site-specific complexities of VOC contamination.
