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Title: Environmental biochemistry of arsenic

Abstract

Microorganisms are involved in the redistribution and global cycling of arsenic. Arsenic can accumulate and can be subject to various biotransformations including reduction, oxidation, and methylation. Bacterial methylation of inorganic arsenic is coupled to the methane biosynthetic pathway in methanogenic bacteria under anaerobic conditions and may be a mechanism for arsenic detoxification. The pathway proceeds by reduction of arsenate to arsenite followed by methylation to dimethylarsine. Fungi are also able to transform inorganic and organic arsenic compounds into volatile methylarsines. The pathway proceeds aerobically by arsenate reduction to arsenite followed by several methylation steps producing trimethylarsine. Volatile arsine gases are very toxic to mammals because they destroy red blood cells (LD50 in rats; 3.0 mg kg-1). Further studies are needed on dimethylarsine and trimethylarsine toxicity tests through inhalation of target animals. Marine algae transform arsenate into non-volatile methylated arsenic compounds (methanearsonic and dimethylarsinic acids) in seawater. This is considered to be a beneficial step not only to the primary producers, but also to the higher trophic levels, since non-volatile methylated arsenic is much less toxic to marine invertebrates. Freshwater algae like marine algae synthesize lipid-soluble arsenic compounds and do not produce volatile methylarsines. Aquatic plants also synthesize similar lipid-soluble arsenicmore » compounds. In terrestrial plants, arsenate is preferentially taken up 3 to 4 times the rate of arsenite. In the presence of phosphate, arsenate uptake is inhibited while in the presence of arsenate, phosphate uptake is only slightly inhibited. There is a competitive interaction between arsenate and phosphate for the same uptake system in terrestrial plants.« less

Authors:
;  [1]
  1. (Department of Soil and Environmental Sciences, University of California, Riverside (United States))
Publication Date:
OSTI Identifier:
5752110
Resource Type:
Journal Article
Resource Relation:
Journal Name: Reviews of Environmental Contamination and Toxicology; (United States); Journal Volume: 124
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; ARSENIC; BIODEGRADATION; ALGAE; AQUATIC ORGANISMS; ENVIRONMENTAL EXPOSURE PATHWAY; FRESH WATER; METHYLATION; MICROORGANISMS; PLANTS; REDOX REACTIONS; SEAWATER; CHEMICAL REACTIONS; DECOMPOSITION; ELEMENTS; HYDROGEN COMPOUNDS; OXYGEN COMPOUNDS; SEMIMETALS; WATER; 560300* - Chemicals Metabolism & Toxicology

Citation Formats

Tamaki, S., and Frankenberger, W.T. Jr. Environmental biochemistry of arsenic. United States: N. p., 1992. Web. doi:10.1007/978-1-4612-2864-6_4.
Tamaki, S., & Frankenberger, W.T. Jr. Environmental biochemistry of arsenic. United States. doi:10.1007/978-1-4612-2864-6_4.
Tamaki, S., and Frankenberger, W.T. Jr. 1992. "Environmental biochemistry of arsenic". United States. doi:10.1007/978-1-4612-2864-6_4.
@article{osti_5752110,
title = {Environmental biochemistry of arsenic},
author = {Tamaki, S. and Frankenberger, W.T. Jr.},
abstractNote = {Microorganisms are involved in the redistribution and global cycling of arsenic. Arsenic can accumulate and can be subject to various biotransformations including reduction, oxidation, and methylation. Bacterial methylation of inorganic arsenic is coupled to the methane biosynthetic pathway in methanogenic bacteria under anaerobic conditions and may be a mechanism for arsenic detoxification. The pathway proceeds by reduction of arsenate to arsenite followed by methylation to dimethylarsine. Fungi are also able to transform inorganic and organic arsenic compounds into volatile methylarsines. The pathway proceeds aerobically by arsenate reduction to arsenite followed by several methylation steps producing trimethylarsine. Volatile arsine gases are very toxic to mammals because they destroy red blood cells (LD50 in rats; 3.0 mg kg-1). Further studies are needed on dimethylarsine and trimethylarsine toxicity tests through inhalation of target animals. Marine algae transform arsenate into non-volatile methylated arsenic compounds (methanearsonic and dimethylarsinic acids) in seawater. This is considered to be a beneficial step not only to the primary producers, but also to the higher trophic levels, since non-volatile methylated arsenic is much less toxic to marine invertebrates. Freshwater algae like marine algae synthesize lipid-soluble arsenic compounds and do not produce volatile methylarsines. Aquatic plants also synthesize similar lipid-soluble arsenic compounds. In terrestrial plants, arsenate is preferentially taken up 3 to 4 times the rate of arsenite. In the presence of phosphate, arsenate uptake is inhibited while in the presence of arsenate, phosphate uptake is only slightly inhibited. There is a competitive interaction between arsenate and phosphate for the same uptake system in terrestrial plants.},
doi = {10.1007/978-1-4612-2864-6_4},
journal = {Reviews of Environmental Contamination and Toxicology; (United States)},
number = ,
volume = 124,
place = {United States},
year = 1992,
month = 1
}
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