title: Quantifying the effects of soil temperature, moisture and sterilization on elemental mercury formation in boreal soils.
abstract: Soils are a source of elemental mercury (Hg(0)) to the atmosphere, however the effects of soil temperature and moisture on Hg(0) formation is not well defined. This research quantifies the effect of varying soil temperature (278-303 K), moisture (15-80% water filled pore space (WFPS)) and sterilization on the kinetics of Hg(0) formation in forested soils of Nova Scotia, Canada. Both, the logarithm of cumulative mass of Hg(0) formed in soils and the reduction rate constants (k values) increased with temperature and moisture respectively. Sterilizing soils significantly (p < 0.05, n = 10) decreased the percent of total Hg reduced to Hg(0). We describe the fundamentals of Hg(0) formation in soils and our results highlight two key processes: (i) a fast abiotic process that peaks at 45% WFPS and depletes a small pool of Hg(0) and; (ii) a slower, rate limiting biotic process that generates a large pool of reducible Hg(II).
authors.affiliation: Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; Department of Earth and Environmental Science, Acadia University, K. C. Irving Environmental Science Center, Wolfville, NS B4P 2R6, Canada.
authors.forename: Ravinder
authors.initials: R
authors.lastname: Pannu
authors.affiliation: Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Siciliano
authors.affiliation: Department of Earth and Environmental Science, Acadia University, K. C. Irving Environmental Science Center, Wolfville, NS B4P 2R6, Canada. Electronic address: nelson.odriscoll@acadiau.ca.
authors.forename: Nelson J
authors.initials: NJ
authors.lastname: O'Driscoll
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D002170:Canada; D006813:Humidity; D008628:Mercury / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D013242:Sterilization; D013696:Temperature; D014197:Trees / Q000737:chemistry
chemical_list: D012987:Soil; D012989:Soil Pollutants; D008628:Mercury
keywords: Kinetics; Mercury reduction; Reaction rates; Soil moisture; Soil sterilization; Soil temperature