Mercury in the terrestrial environment: a review

Abstract

Environmental contamination by mercury is and will continue to be a serious risk for human health. Pollution of the terrestrial environment is particularly important as it is a place of human life and food production. Publication presents a review of the literature on issues related to Hg pollution of the terrestrial environment: soil and plants and their transformations. Different forms of atmospheric Hg may be deposited on surfaces by way of wet and dry processes. These forms may be sequestered within terrestrial compartments or emitted back into the atmosphere, and the relative importance of these processes is dependent on the form of Hg, the surface chemistry, and the environmental conditions. On the land surface, Hg deposition mainly occurs in the oxidized form (Hg 2+ ), and its transformations are associated primarily with the oxidation-reduction potential of the environment and the biological and chemical processes of methylation. The deposition of Hg on ground with low vegetation as 3–5 times lower than that in forests. The estimation of Hg emissions from soil and plants, which occur mainly in the Hg 0 form, is very difficult. Generally, the largest amounts of Hg are emitted from tropical regions, and the lowest levels are from the polar regions.