Interfacial processes on mineral and rock surfaces: attenuation and release of contaminants and preservation of atmospheric processes

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The proposed research focuses on environmental processes at the solid-water and solid-atmosphere interfaces that affect the attenuation, release and preservation of metal(loid)s in the environment. Remediation and reclamation of contaminated soils and mine tailings sites is one of the highest environmental priorities in Canada. Remediation strategies commonly include the simultaneous use of fertilizers and lime. Surface coatings on mineral grains and organic material in these organic, phosphate and metal(loid)-rich soils and tailings facilities control (among other factors) the fate of metal(loid)s. The surfaces of grains and plant roots in these soils and tailings will be examined using a multi-analytical approach that can give us information about chemical processes at the nano- to micrometer scale in remediated soils and tailings. Coatings on exposed rocks are most commonly products of processes at the solid-atmosphere interface. Slow-growing rock coatings can be indicators of climatic change in the Pleistocene and Holocene, whereas coatings formed around smelters and other point sources are records of recent atmospheric pollution. A comparative study of coatings around smelters in Eastern Canada will give insight into the speciation and deposition rate of atmospheric species containing Mercury, Arsenic, Selenium, Lead, Copper, Nickel and Cadmium. Exposed bedrock and relative dry conditions in the Canadian Arctic suggest the widespread occurrence of rock coatings that could be used to deduce the origin and transport paths of atmospheric pollutants to the North. The study of coatings on Melville Island and proximal to the Raglan mine, Northern Quebec will give us an idea whether rock coatings in the Canadian Arctic can be used as indicators for temperature variation and atmospheric pollution.