The ratio of anthropogenic to natural mercury release in Ontario: Three emission scenarios

Mercury is released to the atmosphere by a variety of sources. Anthropogenic sources include fossil fuel combustion and metallurgical processes; natural sources include geological degassing and volcanism. The present study includes an inventory of anthropogenic mercury emissions to air for Ontario in 1993. Anthropogenic emissions in 1993 totalled approximately 12 t; more than 50% of this total originated in metals recovery operations. Natural emissions represented approximately 13% of total emissions (1.7 t per annum). The total Ontario mercury emission to the atmosphere in 1993 was approximately 13.5 t. Three emission scenarios, demonstrating the broad range of natural mercury release estimates for Ontario and resulting policy implications of the scenarios, are discussed.