Measuring gas phase mercury emissions from industrial effluents

A number of hazardous and toxic gaseous species are emitted into the atmosphere from a large variety of industrial-scale processes. Of the trace metal species that have been identified in industrial gaseous emissions, mercury and its compounds (expressed as mercury or Hg) have received the most attention because of the perceived health and environmental risks associated with its release into the atmosphere. Hg emitted from the industrial sources is therefore now recognized as a major concern by governments and environmental bodies worldwide. Anthropogenic emissions have resulted in global atmospheric Hg deposition rates ?3 times higher than in preindustrial times, with increases of 2 to 10 times in and around the most industrialized regions (Hylander and Meili, 2003). The United States Environmental Protection Agency (US-EPA), in its Mercury Study Report to Congress (US-EPA, 1997) in 1997, reported that the amount of mercury released into the atmosphere from human activities in 1995 was between 50% and 75% of the total yearly release (including natural, anthropogenic, and oceanic emissions) of 5500 Mg. The most common estimates for anthropogenic Hg emissions into the atmosphere range between 2000 and 2900 Mg/year.