title: The fate of arsenic adsorbed on iron oxides in the presence of arsenite-oxidizing bacteria.
abstract: Arsenic (As) is a redox-active metalloid whose toxicity and mobility in soil depend on its oxidation state. Arsenite [As(III)] can be oxidized by microbes and adsorbed by minerals in the soil. However, the combined effects of these abiotic and biotic processes are not well understood. In this study, the fate of arsenic in the presence of an isolated As(III)-oxidizing bacterium (Pseudomonas sp. HN-1, 10(9) colony-forming units (CFUs)·ml(-1)) and three iron oxides (goethite, hematite, and magnetite at 1.6 g L(-1)) was determined using batch experiments. The total As adsorption by iron oxides was lower with bacteria present and was higher with iron oxides alone. The total As adsorption decreased by 78.6%, 36.0% and 79.7% for goethite, hematite and magnetite, respectively, due to the presence of bacteria. As(III) adsorbed on iron oxides could also be oxidized by Pseudomonas sp. HN-1, but the oxidation rate (1.3 μmol h(-1)) was much slower than the rate in the aqueous phase (96.2 μmol h(-1)). Therefore, the results of other studies with minerals only might overestimate the adsorptive capacity of solids in natural systems; the presence of minerals might hinder As(III) oxidation by microbes. Under aerobic conditions, in the presence of iron oxides and As(III)-oxidizing bacteria, arsenic is adsorbed onto iron oxides within the adsorption capacity, and As(V) is the primary form in the solid and aqueous phases.
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences, Huaibei Village 380, Huaibei Town, Huairou District, Beijing, 101408, People's Republic of China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, People's Republic of China.
authors.forename: Zhennan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences, Huaibei Village 380, Huaibei Town, Huairou District, Beijing, 101408, People's Republic of China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, People's Republic of China.
authors.forename: Naiyi
authors.initials: N
authors.lastname: Yin
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences, Huaibei Village 380, Huaibei Town, Huairou District, Beijing, 101408, People's Republic of China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, People's Republic of China.
authors.forename: Huili
authors.initials: H
authors.lastname: Du
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences, Huaibei Village 380, Huaibei Town, Huairou District, Beijing, 101408, People's Republic of China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, People's Republic of China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Cai
authors.affiliation: College of Resources and Environment, University of Chinese Academy of Sciences, Huaibei Village 380, Huaibei Town, Huairou District, Beijing, 101408, People's Republic of China; Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing, 100085, People's Republic of China. Electronic address: cuiyanshan@ucas.ac.cn.
authors.forename: Yanshan
authors.initials: Y
authors.lastname: Cui
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000737:chemistry* / Q000378:metabolism; D018053:Arsenites / Q000737:chemistry / Q000378:metabolism*; D005290:Ferric Compounds / Q000737:chemistry*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry*; D010084:Oxidation-Reduction; D011549:Pseudomonas / Q000378:metabolism; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism
chemical_list: D018053:Arsenites; D005290:Ferric Compounds; D058085:Iron Compounds; D008903:Minerals; D012989:Soil Pollutants; C094886:goethite; C000499:ferric oxide; C015001:arsenite; D001151:Arsenic; D052203:Ferrosoferric Oxide
keywords: Arsenic; Arsenite-oxidizing bacteria; Iron oxide