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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, D17304, doi:10.1029/2005JD006563, 2006

Atmospheric mercury emissions from substrates and fumaroles associated with three hydrothermal systems in the western United States

Mark A. Engle

Department of Natural Resources and Environmental Science, University of Nevada, Reno, Nevada, USA

Mae Sexauer Gustin

Department of Natural Resources and Environmental Science, University of Nevada, Reno, Nevada, USA

Fraser Goff

EES-6, Los Alamos National Laboratory, Los Alamos, New Mexico, USA

Dale A. Counce

EES-6, Los Alamos National Laboratory, Los Alamos, New Mexico, USA

Cathy J. Janik

U.S. Geological Survey, Menlo Park, California, USA

Deborah Bergfeld

U.S. Geological Survey, Menlo Park, California, USA

James J. Rytuba

U.S. Geological Survey, Menlo Park, California, USA

Abstract

This paper quantifies atmospheric mercury (Hg) emissions from substrates and fumaroles associated with three hydrothermal systems: Lassen Volcanic Center, California (LVC); Yellowstone Caldera, Wyoming (YC); and Dixie Valley, Nevada (DV). Substrate Hg fluxes were measured using field chamber methods at thermal and nonthermal sites. The highest Hg fluxes (up to 541 ng m⁻² h⁻¹) were measured at thermal active areas. Fluxes from altered and unaltered nonthermal sites were <10 ng m⁻² h⁻¹ and were comparable to those measured in natural low-Hg background regions for YC and DV, and at LVC they were slightly elevated. Similarly, reactive gaseous mercury concentrations were higher in thermal active areas. Using a Geographic Information System framework for scaling, estimated area-average Hg emissions from substrates were 0.9–3.8 ng m⁻² h⁻¹ at LVC, 0.8–2.8 ng m⁻² h⁻¹ at YC, and 0.4–0.5 ng m⁻² h⁻¹ at DV. At LVC, nonthermal areas were the primary substrate source of atmospheric Hg (>98%). At YC, substrate Hg emissions were dominated (50 to 90%) by acidically altered thermal areas. Substrate emissions at DV were low and primarily from nonthermal areas (66% to 75%). Fumarole emissions at LVC (91–146 kg yr⁻¹) and YC (0.18–1.6 kg yr⁻¹ for Mud Volcano) were estimated by applying Hg:H₂O and Hg:CO₂ ratios in hydrothermal gas samples to H₂O and CO₂ emissions. Applying total area-average emissions from substrates and thermal features at LVC, YC, and DV to similar systems across the conterminous United States, yearly atmospheric Hg emissions from active hydrothermal systems are projected to be 1.3–2.1 Mg.

Received 4 August 2005; accepted 9 May 2006; published 7 September 2006.

Keywords: mercury; geothermal; hydrothermal; Lassen; Yellowstone; Dixie Valley.

Index Terms: 0370 Atmospheric Composition and Structure: Volcanic effects (8409); 0489 Biogeosciences: Trace element cycling (4875); 0490 Biogeosciences: Trace gases; 1034 Geochemistry: Hydrothermal systems (0450, 3017, 3616, 4832, 8135, 8424).

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 3581676 bytes)

Citation: Engle, M. A., M. S. Gustin, F. Goff, D. A. Counce, C. J. Janik, D. Bergfeld, and J. J. Rytuba (2006), Atmospheric mercury emissions from substrates and fumaroles associated with three hydrothermal systems in the western United States, J. Geophys. Res., 111, D17304, doi:10.1029/2005JD006563.

Copyright 2006 by the American Geophysical Union.