Mercury loading and methylmercury production and cycling in high-altitude lakes from the Western United States

Water, Air, and Soil Pollution: Focus
By: , and 



Studies worldwide have shown that mercury (Hg) is a ubiquitous contaminant, reaching even the most remote environments such as high-altitude lakes via atmospheric pathways. However, very few studies have been conducted to assess Hg contamination levels of these systems. We sampled 90 mid-latitude, high-altitude lakes from seven national parks in the western United States during a four-week period in September 1999. In addition to the synoptic survey, routine monitoring and experimental studies were conducted at one of the lakes (Mills Lake) to quantify MeHg fluxrates and important process rates such as photo-demethylation. Results show that overall, high-altitude lakes have low total mercury (HgT) and methylmercury (MeHg) levels (1.07 and 0.05 ng L-1, respectively), but a very good correlation of Hg to MeHg (r2= 0.82) suggests inorganic Hg(II) loading is a primary controlling factor of MeHg levels in dilute mountain lakes. Positive correlations were also observed for dissolved organic carbon (DOC) and both Hg and MeHg, although to a much lesser degree. Levels of MeHg were similar among the seven national parks, with the exception of Glacier National Park where lowerconcentrations were observed (0.02 ng L-1), and appear to be related to naturally elevated pH values there. Measured rates ofMeHg photo-degradation at Mills Lake were quite fast, and this process was of equal importance to sedimentation and stream flow for removing MeHg. Enhanced rates of photo-demethylation are likely an important reason why high-altitude lakes, with typically high water clarity and sunlight exposure, are low in MeHg.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Mercury loading and methylmercury production and cycling in high-altitude lakes from the Western United States
Series title Water, Air, and Soil Pollution: Focus
DOI 10.1023/A:1020162811104
Volume 2
Issue 2
Year Published 2002
Language English
Publisher Kluwer Academic Publishers
Contributing office(s) Toxic Substances Hydrology Program
Description 17 p.
First page 233
Last page 249
Country United States
State California, Colorado, Montana, Wyoming
Other Geospatial Glacier National Park, Grand Teton National Park, Lassen Volcanic National Park, Rocky Mountain National Park, Sequoia National Park, Yellowstone National Park, Yosemite National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
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