Contaminant behaviour applied to the remediation of soils and sediments using an integrated multidisciplinary approach

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Canada counts with 1221 federal contaminated sites. About one third is located in Quebec, British Columbia and Ontario. Each province has its own similar number of sites of local responsibility. Ports along the St-Lawrence sea way dredge over 200 000 ton/year of contaminated sediments and numerous Canadian lakes suffer from early (anthropogenic) eutrophication associated to phosphorus released from sediments with consequent production of toxic algae (cyanobacteria). Similar situations are found in US, Mexico and Europe making of contaminated soils and sediments a worldwide and serious environmental problem. Pollution problems have arisen from the inadequate disposal of industrial effluents, polluted urban/agricultural runoffs and hazardous waste storage that contaminated water/sediments in rivers/lakes; or soils/groundwater in contaminated sites. Pollutants considered retained by soils/sediments pose risk to ecosystems and human health because of mechanisms that trigger their release. Typical contaminants found in soil/sediments are: excess nutrients (P and N), heavy metals (Pb, Cd, Cr, Zn), petroleum hydrocarbons and of recent/higher concern, road de-icing salts. The global aim of this research program is to understand a pollution problem holistically and to propose technical means to attenuate; protect, and restore sites following sustainable development principles. Specifically, 3 aspects of contaminated soil/sediments remediation will be studied in laboratory using field samples from real case studies: 1) study of contaminant behaviour with emphasis on the influence of common anionic contaminants in the mobilization of heavy metals, physical distribution and potential for transport; 2) relation between geochemical speciation and availability, transformation and aging process; 3) Conception and design of geo-liners for the treatment or isolation of contaminants; the barriers are to be technically and environmentally sound/tested in laboratory at meso/large columns and they will mimic real case studies within watershed or hydrogeological systems.