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Mercury methylation at mercury mines in the Humboldt River Basin, Nevada, USA

Geochemistry: Exploration, Environment, Analysis

By:
, , and
DOI: 10.1144/1467-787302-017

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Abstract

Total Hg and methylmercury concentrations were measured in mine-waste calcines (retorted ore), sediment, and water samples collected in and around abandoned mercury mines in western Nevada to evaluate Hg methylation at the mines and in the Humboldt River Basin. Mine-waste calcines contain total Hg concentrations as high as 14 000 ??g g-1. Stream-sediment samples collected within 1 km of the mercury mines contain total Hg concentrations as high as 170 ??g g-1, whereas stream sediments collected at a distance >5 km from the mines, and those collected from the Humboldt River and regional baseline sites, contain total Hg concentrations <0.5 ??g g-1. Similarly, methylmercury concentrations in mine-waste calcines are locally as high as 96 ng g-1, but methylmercury contents in stream sediments collected downstream from the mines and from the Humboldt River are lower, ranging from <0.05 to 0.95 ng g-1. Stream-water samples collected downstream from two mines studied contain total Hg concentrations ranging from 6 to 2000 ng 1-1, whereas total Hg in Humboldt River water was generally lower, ranging from 2.1 to 9.0 ng 1-1. Methylmercury concentrations in the Humboldt River water were the lowest in this study (<0.02-0.27 ng 1-1). Although total Hg and methylmercury concentrations are locally high in mine-waste calcines, there is significant dilution of Hg and there is also lower Hg methylation down gradient from the mines, especially in the sediments and water collected from the Humboldt River, which is >8 km from the nearest mercury mines. Our data indicate little transference of Hg and methylmercury from the sediment to the water column due to the lack of mine runoff in this desert climate.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Mercury methylation at mercury mines in the Humboldt River Basin, Nevada, USA
Series title:
Geochemistry: Exploration, Environment, Analysis
DOI:
10.1144/1467-787302-017
Volume
2
Issue:
2
Year Published:
2002
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geochemistry: Exploration, Environment, Analysis
First page:
143
Last page:
149