Anoxic oxidation of arsenite linked to denitrification in sludges and sediments

WATER RESEARCH

卷:42

Article

Sun, Wenjie¹  Sierra, Reyes¹  Field, Jim A.¹ 

[1] Univ Arizona, Dept Chem & Environm Engn, Tucson, AZ 85721 USA

关键词: Chemolithotrophic;    Arsenic;    Arsenate;    Nitrate;    Anaerobic;    Biotransformation;   

DOI  :  10.1016/j.watres.2008.08.004

来源: Elsevier

【 摘 要 】

In this study, denitrification linked to the oxidation of arsenite (As(III)) to arsenate (As(V)) was shown to be a widespread microbial activity in anaerobic sludge and sediment samples that were not previously exposed to arsenic contamination. When incubated with 0.5 mM As(III) and 10 mM NO (-) over bar3, the anoxic oxidation of As(III) commenced within a few days, achieving specific activities of up to 1.24 mmol As(V) formed g(-1) volatile suspended solids d(-1) due to growth (doubling times of 0.74-1.4 d). The anoxic oxidation of As(III) was partially to completely inhibited by 1.5 and 5 mM As(III), respectively. Inhibition was minimized by adding As(III) adsorbed onto activated aluminum (AA). The oxidation of As(III) was shown to be linked to the complete denitrification of NO (-) over bar (3) to N-2 by demonstrating a significantly enhanced production of N2 beyond the background endogenous production as a result of adding As(III)-AA to the cultures. The N2 production corresponded closely the expected stoichiometry of the reaction, 2.5 mol As(III) mol(-1)N(2)-N. The oxidation of As(III) linked to the use of common-occurring nitrate as an electron acceptor may be an important missing link in the biogeochemical cycling of arsenic. (C) 2008 Elsevier Ltd. All rights reserved

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