Linking geochemical processes in mud volcanoes with arsenic mobilization driven by organic matter

Liu, Chia-Chuan and Kar, Sandeep and Jean, Jiin-Shuh and Wang, Chung-Ho and Lee, Yao-Chang and Sracek, Ondra and Li, Zhaohui and Bundschuh, Jochen and Yang, Huai-Jen and Chen, Chien-Yen (2013) Linking geochemical processes in mud volcanoes with arsenic mobilization driven by organic matter. Journal of Hazardous Materials , 262. pp. 980-988. ISSN 0304-3894

Abstract

The present study deals with geochemical characterization of mud fluids and sediments collected from Kunshuiping (KSP), Liyushan (LYS), Wushanting (WST), Sinyangnyuhu (SYNH), Hsiaokunshui (HKS) and Yenshuikeng (YSK) mud volcanoes in southwestern Taiwan. Chemical constituents (cations, anions, trace elements, organic carbon, humic acid, and stable isotopes) in both fluids and mud were analyzed to investigate the geochemical processes and spatial variability among the mud volcanoes under consideration. Analytical results suggested that the anoxic mud volcanic fluids are highly saline, implying connate water as the probable source. The isotopic signature indicated that δ 18O-rich fluids may be associated with silicate and carbonate mineral released through water-rock interaction, along with dehydration of clay minerals. Considerable amounts of arsenic in mud irrespective of fluid composition suggested possible release through biogeochemical processes in the subsurface environment. Sequential extraction of As from the mud indicated that As was mostly present in organic and sulphidic phases, and adsorbed on amorphous Mn oxyhydroxides. Volcanic mud and fluids are rich in organic matter (in terms of organic carbon), and the presence of humic acid in mud has implications for the binding of arsenic. Functional groups of humic acid also showed variable sources of organic matter among the mud volcanoes being examined. Because arsenate concentration in the mud fluids was found to be independent from geochemical factors, it was considered that organic matter may induce arsenic mobilization through an adsorption/desorption mechanism with humic substances under reducing conditions. Organic matter therefore plays a significant role in the mobility of arsenic in mud volcanoes.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2012 Elsevier B.V. All rights reserved. Published online 30 June 2012. Permanent restricted access to published version in accordance with the copyright policy of the publisher.
Depositing User: epEditor USQ
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 27 Aug 2012 00:02
Last Modified: 14 Oct 2014 22:48
Uncontrolled Keywords: arsenic mobilization; geochemical processes; mud volcanoes; organic matter; Taiwan
Fields of Research (FOR2008): 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology
03 Chemical Sciences > 0399 Other Chemical Sciences > 039901 Environmental Chemistry (incl. Atmospheric Chemistry)
04 Earth Sciences > 0402 Geochemistry > 040204 Organic Geochemistry
Socio-Economic Objective (SEO2008): E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: 10.1016/j.jhazmat.2012.06.050
URI: http://eprints.usq.edu.au/id/eprint/21686

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