Historically, smelters have been a major source of metals and SO2 released to the environment in Canada. The study of emissions in the environment around smelters is therefore a priority in evaluating policies in relation to sustainable development. This Special Issue is devoted to papers on various projects supported under three Canadian programmes on metals in the environment. Scientific questions addressed by these programmes include understanding how emitted metals impact the surface environment in different settings, estimating the smelter outputs of metals, distinguishing smelter-derived releases from geogenic contributions, and understanding the fate of current emissions of metals and metalloids and their accumulation during the twentieth century. The approach of the scientific team involved characterizing the spatio-temporal distribution of smelter-emitted metals in the plume and in various surficial media around selected Canadian smelters.
This overview paper summarizes some of the findings discussed in the Special Issue, specifically that: (1) smelter-emitted metal-bearing solids have characteristics that allow their quantification and permit the evaluation of their contribution to the metal load of natural media; (2) delineation of smelter ‘footprints’ can be approached by mathematical estimation or by measurement of multi-element or isotope ratios; and (3) investigation of archival geological systems provides time series that reflect the point-source inputs.