title: Assessment of Global Mercury Deposition through Litterfall.
abstract: There is a large uncertainty in the estimate of global dry deposition of atmospheric mercury (Hg). Hg deposition through litterfall represents an important input to terrestrial forest ecosystems via cumulative uptake of atmospheric Hg (most Hg(0)) to foliage. In this study, we estimate the quantity of global Hg deposition through litterfall using statistical modeling (Monte Carlo simulation) of published data sets of litterfall biomass production, tree density, and Hg concentration in litter samples. On the basis of the model results, the global annual Hg deposition through litterfall is estimated to be 1180 ± 710 Mg yr(-1), more than two times greater than the estimate by GEOS-Chem. Spatial distribution of Hg deposition through litterfall suggests that deposition flux decreases spatially from tropical to temperate and boreal regions. Approximately 70% of global Hg(0) dry deposition occurs in the tropical and subtropical regions. A major source of uncertainty in this study is the heterogeneous geospatial distribution of available data. More observational data in regions (Southeast Asia, Africa, and South America) where few data sets exist will greatly improve the accuracy of the current estimate. Given that the quantity of global Hg deposition via litterfall is typically 2-6 times higher than Hg(0) evasion from forest floor, global forest ecosystems represent a strong Hg(0) sink.
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , Guiyang 550081, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Center for Advances in Water and Air Quality, Lamar University , Beaumont, Texas 77710-0080, United States.|Department of Civil and Environmental Engineering, Lamar University , Beaumont, Texas 77710-0080, United States.
authors.forename: Zhengduo
authors.initials: Z
authors.lastname: Bao
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , Guiyang 550081, China.|Center for Advances in Water and Air Quality, Lamar University , Beaumont, Texas 77710-0080, United States.|Department of Civil and Environmental Engineering, Lamar University , Beaumont, Texas 77710-0080, United States.
authors.forename: Che-Jen
authors.initials: CJ
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , Guiyang 550081, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , Guiyang 550081, China.
authors.forename: Xinbin
authors.initials: X
authors.lastname: Feng
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring; D065928:Forests; D008628:Mercury / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry*; D014197:Trees
chemical_list: D000393:Air Pollutants; D008628:Mercury