Open AccessGaseous mercury in background forest soil in the northeastern United States
Author(s) -
Sigler Jeffrey M.,
Lee Xuhui
Publication year - 2006
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2005jg000106
Subject(s) - mercury (programming language) , environmental chemistry , environmental science , soil water , soil horizon , flux (metallurgy) , atmosphere (unit) , soil science , chemistry , meteorology , computer science , programming language , physics , organic chemistry
Although the soil gaseous mercury (Hg) reservoir is an important component of the soil Hg emission process, little is known of the behavior of gaseous Hg in soil pores and the processes governing the ultimate evasion of Hg from soil surfaces. In this study, gaseous Hg in background forest soil in the northeastern United States was examined during 2003 and 2004 using a novel flask sampling technique. This represents the first detailed study of gaseous Hg concentration within the soil profile. Soil gaseous Hg varied seasonally with soil temperature, and highest concentrations consistently occurred in the O‐ and upper A‐horizons. The study revealed clear gradients in gaseous Hg concentrations, which bore striking resemblance to gradients in bound Hg. In addition, measurements of soil Hg flux were correlated with soil gaseous Hg concentrations at 2 cm depth. These results indicate that the upper soil layers, rich in bound Hg, act as a source of gaseous Hg that may ultimately be emitted to the atmosphere. Large changes in soil gaseous Hg over shallow layers underscore the importance of fine vertical resolution of measurements, and therefore the utility of flask sampling.