Mercury in the Atmospheric and Coastal Environments of Mexico

Though mercury (Hg) occurs naturally in the environment, anthropogenic activities have affected its global cycle in ways that mobilize increasing amounts of this metal; currently, such human-related activities mobilize more Hg than do natural processes (Fitzgerald and Lamborg 2005). It has been estimated that the quantity of Hg mobilized into the atmosphere has increased from two to five times (Nriagu and Pacyna 1988) since the beginning of the industrial age. The mercury cycle is complex and involves diverse environmental media that include air, land, and water. For any country that is not landlocked, the estuaries and coastal waters constitute an important link between the terrestrial environment and the open oceanic waters (Mason et al. 1994). However, research thus far performed on Hg as an environmental contaminant has been focused mainly on terrestrial ecosystems (Fitzgerald and Mason 1996). The focus on land contamination by Hg has occurred despite the prominent role played by Hg in the atmosphere (transported by wind and deposited under both dry and wet conditions) and in oceanic processes (horizontal and vertical transportation, accumulation in sediments, and bacterial transformations).