Releases from copper smelters and refineries and zinc plants in Canada: human health exposure and risk characterization

In these assessments of releases from copper smelters and refineries and from zinc plants as Priority Substances under the Canadian Environmental Protection Act (CEPA), available data were critically evaluated to determine if environmental exposure to selected components of these releases poses a risk to human health. The data on airborne levels of a variety of toxic substances near these facilities in Canada were obtained from the companies or provinces and systematically analyzed. Monitoring of ambient air near the Canadian copper smelters and refineries and zinc plants indicates that releases from these facilities result in increased potential for inhalation exposure of local human populations to several components of releases (As, Cd, Cr, Ni, Pb, SO2 and PM10). Airborne levels in the vicinity of these metal-processing operations overlap those associated with cardiorespiratory effects for PM10, and exceed health-based guidelines for SO2 and, near some facilities, Pb. In addition, the margin between levels of As, Cd, Cr and Ni near these facilities in Canada and carcinogenic potency for each of these metals is relatively small near copper smelters, larger near copper refineries, and intermediate near zinc plants. On this basis, the risk to human health from environmental exposure to releases from these facilities is considered to be high compared with other Priority Substances assessed under CEPA, especially for facilities where copper is smelted.