Grant: Alliance Grants

Open pit mining of the Athabasca Bituminous Sands in northern Alberta generates considerablevolumes of dust. The dusts are dominated by coarse-grained minerals that are largely insolublesuch as quartz, but also fine-grained minerals and more reactive phases such as carbonates. Thedusts contain varying amounts of trace elements (TEs), some of which may be released to surfacewaters upon deposition from the air. Some TEs are benign, some are essential micronutrients, butsome may be toxic. Peat bog waters which are naturally acidic (pH 4), offer a chance to study theextent to which these dusts dissolve in the peatlands that dominate the landscape. By measuringthe concentrations of TEs in bog waters, the chemical reactivity of the dust particles can bejudged, and along with it, the bioavailability of TEs. In this sense, peat bogs represent naturalbiomonitoring systems that can be used to identify the chemical reactivity of atmosphericparticles. Sphagnum moss is the dominant plant in bogs, and is typically 90% water by weight.Porewater expressed from Sphagnum will be used to study the reactivity of these particles, as wellas water extracted from country foods such as wild berries, and traditional medicinal plants suchas the Pitcher Plant (Sarracenia purpurea). Using AF4-ICP-MS (asymmetric flow field flowfractionation coupled to inductively coupled plasma mass spectrometry), size-resolved analyseswill allow colloidal forms of TEs (which are not bioavailable) to be distinguished from "trulydissolved", predominantly ionic species (which are bioavailable). Experimental studies in thelaboratory using simple organic acids will be used to understand the mechanisms of mineraldissolution, and the influence of complexation reactions on the speciation of TEs. The study willprovide new insight into the true environmental impacts of bitumen mining and upgrading.