TY - JOUR
T1 - Natural attenuation process via microbial oxidation of arsenic in a high Andean watershed
AU - Leiva, Eduardo D.
AU - Rámila, Consuelo d.P.
AU - Vargas, Ignacio T.
AU - Escauriaza, Cristian R.
AU - Bonilla, Carlos A.
AU - Pizarro, Gonzalo E.
AU - Regan, John M.
AU - Pasten, Pablo A.
N1 - Funding Information:
This research was supported by a FONDECYT 1100943/2010 , a FONDECYT 1130936/2013 , and a CONICYT grant 24121233/2012 , as well as Fulbright Scholar Award 9561 for J.M.R. This study was also partially supported by a CORFO 09CN14-5709 grant and a CONICYT/FONDAP 15110020 grant. Thanks are extended to the reviewers for the corrections and suggestions, which significantly improved the manuscript.
PY - 2014
Y1 - 2014
N2 - Rivers in northern Chile have arsenic (As) concentrations at levels that are toxic for humans and other organisms. Microorganism-mediated redox reactions have a crucial role in the As cycle; the microbial oxidation of As (As(III) to As(V)) is a critical transformation because it favors the immobilization of As in the solid phase. We studied the role of microbial As oxidation for controlling the mobility of As in the extreme environment found in the Chilean Altiplano (i.e., >. 4000. meters above sea level (masl) and < 310. mm annual rainfall), which are conditions that have rarely been studied. Our model system was the upper Azufre River sub-basin, where the natural attenuation of As from hydrothermal discharge (pH. 4-6) was observed. As(III) was actively oxidized by a microbial consortium, leading to a significant decrease in the dissolved As concentrations and a corresponding increase in the sediment's As concentration downstream of the hydrothermal source. In-situ oxidation experiments demonstrated that the As oxidation required biological activity, and microbiological molecular analysis confirmed the presence of As(III)-oxidizing groups (aroA-like genes) in the system. In addition, the pH measurements and solid phase analysis strongly suggested that the As removal mechanism involved adsorption or coprecipitation with Fe-oxyhydroxides. Taken together, these results indicate that the microorganism-mediated As oxidation contributed to the attenuation of As concentrations and the stabilization of As in the solid phase, therefore controlling the amount of As transported downstream. This study is the first to demonstrate the microbial oxidation of As in Altiplano basins and its relevance in the immobilization of As.
AB - Rivers in northern Chile have arsenic (As) concentrations at levels that are toxic for humans and other organisms. Microorganism-mediated redox reactions have a crucial role in the As cycle; the microbial oxidation of As (As(III) to As(V)) is a critical transformation because it favors the immobilization of As in the solid phase. We studied the role of microbial As oxidation for controlling the mobility of As in the extreme environment found in the Chilean Altiplano (i.e., >. 4000. meters above sea level (masl) and < 310. mm annual rainfall), which are conditions that have rarely been studied. Our model system was the upper Azufre River sub-basin, where the natural attenuation of As from hydrothermal discharge (pH. 4-6) was observed. As(III) was actively oxidized by a microbial consortium, leading to a significant decrease in the dissolved As concentrations and a corresponding increase in the sediment's As concentration downstream of the hydrothermal source. In-situ oxidation experiments demonstrated that the As oxidation required biological activity, and microbiological molecular analysis confirmed the presence of As(III)-oxidizing groups (aroA-like genes) in the system. In addition, the pH measurements and solid phase analysis strongly suggested that the As removal mechanism involved adsorption or coprecipitation with Fe-oxyhydroxides. Taken together, these results indicate that the microorganism-mediated As oxidation contributed to the attenuation of As concentrations and the stabilization of As in the solid phase, therefore controlling the amount of As transported downstream. This study is the first to demonstrate the microbial oxidation of As in Altiplano basins and its relevance in the immobilization of As.
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U2 - 10.1016/j.scitotenv.2013.07.009
DO - 10.1016/j.scitotenv.2013.07.009
M3 - Article
C2 - 23933432
AN - SCOPUS:84881504422
SN - 0048-9697
VL - 466-467
SP - 490
EP - 502
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -