Fig. 1: Deposition pathways for mercury in the environment in the process of burning a mercury (Hg)–gold (Au) amalgam.
From: Amazon forests capture high levels of atmospheric mercury pollution from artisanal gold mining
Mercury emitted as gaseous elemental mercury (GEM; Hg0) can undergo three atmospheric pathways to be deposited onto the landscape. First, GEM can be oxidized to ionic Hg (Hg2+), which can be entrained in water droplets and deposited as wet or dry deposition to foliar surfaces. Second, GEM can sorb to atmospheric particles (Hgp), which are intercepted by leaves and, along with intercepted ionic Hg, washed onto the landscape via throughfall. Third, GEM can be taken up into leaf tissue, and the Hg deposited onto the landscape as litterfall. Throughfall and litterfall together are considered as an estimate of total Hg deposition. While GEM may also diffuse into and adsorb onto soils and litter directly77, this is likely not a major pathway for Hg entry into the terrestrial ecosystem.
