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Título : | Microbially Mediated Release of As from Mekong Delta Peat Sediments |
Autor : | Asta, Maria P. Wang, Yuheng Frutschi, Manon Viacava, Karen Loreggian, Luca Le Pape, Pierre Le Vo, Phu Fernández, Ana María Morin, Guillaume Bernier-Latmani, Rizlan |
Palabras clave : | Microbial activity Arsenic porewater sediments |
Fecha de publicación : | 29-ene-2025 |
Citación : | Maria P. Asta, Yuheng Wang, Manon Frutschi, Karen Viacava, Luca Loreggian, Pierre Le Pape, Phu Le Vo, Ana María Fernández, Guillaume Morin, and Rizlan Bernier-Latmani Environmental Science & Technology 2019 53 (17), 10208-10217 DOI: 10.1021/acs.est.9b02887 |
Citación : | Environmental Science & Technology;53 |
Resumen : | Peat layers within alluvial sediments are considered effective arsenic (As) sinks under reducing conditions due to the binding of As(III) to thiol groups in natural organic matter (NOM) and the formation of As-bearing sulfide phases. However, their possible role as sources of As for anoxic groundwaters remains unexplored. Here, we perform laboratory experiments to provide evidence for the role of a sediment peat layer in releasing As. Our results show that the peat layer, deposited about 8,000 years ago in a paleomangrove environment in the nascent Mekong Delta, could be a source of As to porewater under reducing conditions. X-ray absorption spectroscopy (XAS) analysis of the peat confirmed that As was bound to NOM thiol groups and incorporated into pyrite. Nitrate was detected in peat layer porewater, and flow-through and batch experiments evidenced the release of As from NOM and pyrite in the presence of nitrate. Based on poisoning experiments, we propose that the microbially mediated oxidation of arsenic-rich pyrite and organic matter coupled to nitrate reduction releases arsenic from this peat. Although peat layers have been proposed as As sinks in earlier studies, we show here their potential to release depositional- and/or diagenetically-accumulated As. |
URI : | http://documenta.ciemat.es/handle/123456789/4462 |
ISSN : | 0013-936X |
Aparece en las colecciones: | Artículos de Fisión Nuclear
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