Biogeochemistry of Mercury in the Amazonian Environment

In this paper, the processes that affect mercury (Hg) cycling in the Amazonian environment were reviewed, criticized and new directions of research are proposed. The discussion of the origin of the mercury contamination, whether natural or anthropogenic is marked by a lack of fundamented arguments f...

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Bibliographic Details
Published in:Ambio 2003-08, Vol.32 (5), p.336-342
Main Authors: Wasserman, Julio Cesar, Hacon, Sandra, Wasserman, Maria Angélica
Format: Article
Language:English
Subjects:
Alkylation
Brazil
Environmental Monitoring
Environmental Pollutants - analysis
Forest soils
Geochemistry
Geological Phenomena
Geology
Gold
Gold mining
Mercury
Mercury - analysis
Mercury - chemistry
Methylation
Mining
Risk Assessment
Sedimentary soils
Sediments
Soil pollution
Soil water
Water pollution
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Summary:In this paper, the processes that affect mercury (Hg) cycling in the Amazonian environment were reviewed, criticized and new directions of research are proposed. The discussion of the origin of the mercury contamination, whether natural or anthropogenic is marked by a lack of fundamented arguments from both sides. Undoubtedly mercury inputs from gold mining have locally increased environmental concentrations, but in the whole Amazon, these loads would be insignificant, considering the high concentrations observed by some authors in remote soils. A reasonable process that should explain these elevated concentrations in soil is that B horizons function as a mercury “sponge” that have been accumulating mercury over a geological time scale, releasing it back to cycling during erosion and forest fires. The environmental degradation of the Amazonian forest due to human activities is probably enhancing the release of that mercury to the cycle. Mercury transformations in reduced, anoxic environments—sediments and waters—are also a key problem for the understanding of the environmental methylation. The studies that have been carried out in the Amazonian environment are too restricted and results permit only circumstantial conclusions. Large efforts must be directed to monitoring programs considering time and space variability.
ISSN:0044-7447
1654-7209
DOI:10.1579/0044-7447-32.5.336