A conceptual system for assigning sensitivities to potentially acidifying inputs to soils in the oil sands region of Alberta

Concerns have been raised about the possible cumulative effects on the boreal ecosystem of potentially acidifying inputs released in the region because of the proliferation of active, approved and planned oil sand developments. A concern is the sensitivities of the various organic and mineral soils in the area to continued acidifying inputs. The development of an approach for assigning relative sensitivity classes of low, moderate and high to regional soils is outlined, and the results of applying the method to a particular emissions scenario are illustrated. Because the method is qualitative only, its greatest use consists in indicating which soils have the greatest potential susceptibility to acidification, both with respect to specific soil series and geographical location: the soils so identified might be candidates for inclusion in future monitoring programs. The approach requires verification and refinement by ongoing field work and sensitivity modelling to enhance the level of confidence in its accuracy. Given the spatial extent, relative inaccessibility, and limited soil data available for the boreal forest, an empirical rating system of this kind offers the most practical tool for determining the potential impacts of emissions in the area. (Abstract only)