Mercury in Biota

Abstract

Terrestrial vegetation interacts with both soil and the atmosphere in the acquisition of Hg (Siegel et al. 1987). We have shown in previous chapters the importance of atmospheric Hg in the geochemical cycles in gold mining areas. Terrestrial plants can take up Hg from the atmosphere directly through gas exchange at the stomatal level or through membrane exchange with wet and dry precipitation (Browne and Fang 1978). These processes are likely to be enhanced in tropical vegetation due to the efficient mechanisms of chemical element acquisition from the atmosphere mediated by epiphyllous organisms, in particular algae and lichens (Jordan et al. 1980) at the crown leaf level, and those mediated by the high diversity and biomass of ephiphytes typical of most tropical ecosystems (Benzing 1981; Nadkarni 1984).