Transport of elemental mercury in the unsaturated zone from a waste disposal site in an arid region

Applied Geochemistry
By: , and 

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Abstract

Mercury contained in buried landfill waste may be released via upward emission to the atmosphere or downward leaching to groundwater. Data from the US Geological Survey’s Amargosa Desert Research Site (ADRS) in arid southwestern Nevada reveal another potential pathway of Hg release: long-distance (102 m) lateral migration of elemental Hg (Hg0) through the unsaturated zone. Gas collected from multiple depths from two instrumented boreholes that sample the entire 110-m unsaturated zone thickness and are located 100 and 160 m away from the closest waste burial trench exhibit gaseous Hg concentrations of up to 33 and 11 ng m−3, respectively. The vertical distribution of gaseous Hg in the borehole closest to the disposal site shows distinct subsurface peaks in concentration at depths of 1.5 and 24 m that cannot be explained by radial diffusive transport through a heterogeneous layered unsaturated zone. The inability of current models to explain gaseous Hg distribution at the ADRS highlights the need to advance the understanding of gas-phase contaminant transport in unsaturated zones to attain a comprehensive model of landfill Hg release.

Publication type Article
Publication Subtype Journal Article
Title Transport of elemental mercury in the unsaturated zone from a waste disposal site in an arid region
Series title Applied Geochemistry
DOI 10.1016/j.apgeochem.2007.12.014
Volume 23
Issue 3
Year Published 2008
Language English
Publisher Elsevier
Contributing office(s) Nevada Water Science Center, Toxic Substances Hydrology Program
Description 12 p.
First page 572
Last page 583
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