Leaching, transport, and methylation of mercury in and around abandoned mercury mines in the Humboldt River basin and surrounding areas, Nevada

Bulletin 2210-C
By:  and 



Mercury and methylmercury concentrations were measured in mine wastes, stream sediments, and stream waters collected both proximal and distal from abandoned mercury mines to evaluate mercury contamination and mercury methylation in the Humboldt River system. The climate in the study area is arid, and due to the lack of mine-water runoff, water-leaching laboratory experiments were used to evaluate the potential of mine wastes to release mercury. Mine-waste calcine contains mercury concentrations as high as 14,000 µg/g. Stream-sediment samples collected within 1 km of the mercury mines studied contain mercury concentrations as high as 170 µg/g, but sediments collected from the Humboldt River and regional baseline sites have much lower mercury contents, less than 0.44 µg/g. Similarly, methylmercury concentrations in mine-waste calcine are locally as high as 96 ng/g, but methylmercury contents in stream sediments collected downstream from the mines and from the Humboldt River are lower (<0.05–0.95 ng/g). Stream-water samples collected below two mines studied contain mercury concentrations ranging from 6 to 2,000 ng/L, whereas mercury contents in Humboldt River and Rye Patch Reservoir water were generally lower, ranging from 2.1 to 9.0 ng/L. Methylmercury concentrations in Humboldt River system water were the lowest in this study (<0.02– 0.27 ng/L). Although mercury and methylmercury concentrations were elevated in some mine-waste calcine and mercury concentrations were locally high in mine-waste leachate samples, data show significant dilution of mercury and lower mercury methylation down gradient from the mines, especially in the sediments and water collected from the Humboldt River, which is more than 8 km from any mercury mines. Data show only minor, local transference of mercury and methylmercury from mine-waste calcine to stream sediment, and then onto the water column, and indicate little transference of mercury from the mine sites to the Humboldt River system.

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Publication type Report
Publication Subtype USGS Numbered Series
Title Leaching, transport, and methylation of mercury in and around abandoned mercury mines in the Humboldt River basin and surrounding areas, Nevada
Series title Bulletin
Series number 2210
Chapter C
DOI 10.3133/b2210C
Edition Version 1.0
Year Published 2003
Language English
Publisher U.S. Geological Survey
Contributing office(s) Central Mineral and Environmental Resources Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Description v, 15 p.
Larger Work Type Report
Larger Work Subtype USGS Numbered Series
Larger Work Title Geoenvironmental Investigations of the Humboldt River Basin, Northern Nevada
Time Range Start 1995-01-01
Time Range End 2000-12-31
Country United States
State Nevada
Other Geospatial Humboldt River basin
Scale 0
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