title: Anaerobic biotransformation of organo-arsenical pesticides monomethylarsonic acid and dimethylarsinic acid.
abstract: Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organo-arsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively.
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, Arizona, P. O. Box 210011, Tucson, Arizona 85721, USA.
authors.forename: Reyes
authors.initials: R
authors.lastname: Sierra-Alvarez
authors.forename: Umur
authors.initials: U
authors.lastname: Yenal
authors.forename: Jim A
authors.initials: JA
authors.lastname: Field
authors.forename: Mike
authors.initials: M
authors.lastname: Kopplin
authors.forename: A Jay
authors.initials: AJ
authors.lastname: Gandolfi
authors.forename: John R
authors.initials: JR
authors.lastname: Garbarino
mesh_terms: D000693:Anaerobiosis; D001152:Arsenicals / Q000378:metabolism*; D002101:Cacodylic Acid / Q000378:metabolism*; D007700:Kinetics; D010575:Pesticides / Q000378:metabolism*; D012722:Sewage; D012988:Soil Microbiology
chemical_list: D001152:Arsenicals; D010575:Pesticides; D012722:Sewage; D002101:Cacodylic Acid; C020300:monomethylarsonic acid