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| 題名: | Hydrochemical, mineralogical and isotopic investigation of arsenic distribution and mobilization in the Guandu wetland of Taiwan |
| 作者: | 王聖瑋;Kao, Yu-Hsuan;Wang, Sheng-Wei;Maji, Sanjoy Kumar;Liu, Chen-Wuing;Wang, Pei-Ling;Chang, Fi-John;Liao, Chung-Min |
| 貢獻者: | 工學院土木工程學系 |
| 關鍵詞: | adsorption;anaerobic conditions;Arsenic;Bacteria;cluster analysis;desorption;Dissolution;Earth sciences;Earth, ocean, space;Engineering and environment geology. Geothermics;Exact sciences and technology;Hydrology;Hydrology. Hydrogeology;Iron;Isotope geochemistry;Isotope geochemistry. Geochronology;metals;Mineralogical compositions;organic matter;Oxidation;oxides;Pollution, environment geology;Redox cycling;Sediments;Stable sulfur isotope;sulfates;sulfides;Sulfur;Surface chemistry;Taiwan;Wetland ecosystem;Wetlands |
| 日期: | 2013-08-19 |
| 上傳時間: | 2026-04-21 13:36:07 (UTC+8) |
| 出版者: | Elsevier;Kidlington: Elsevier B.V |
| 摘要: | 摘要： •Distribution and mobilization of As in the Guandu wetland were investigated.•As mobility occurred in the boundary between the Fe-reducing and sulfate-reducing conditions.•High aqueous As was caused by the reductive dissolution of solid Fe compounds.•Enriched δ34S[SO4] and δ18S[SO4] values implies significant dissimilatory sulfate reduction.•Arsenic mobility in wetland ecosystem is controlled by redox cycling of Fe, S and C. This study explores the distribution and mobilization of As in the ecosystem of the Guandu wetlands, Taiwan. The chemical parameters, chemical sequential extraction, mineralogical compositions, and sulfur isotopic compositions (i.e., δ34S[SO4] and δ18S[SO4]) of porewater and two sediment core samples (S2 and S5, locate in the inner and outer sites of the Guandu wetland) were analyzed to characterize As spatial distribution. The crucial mechanisms of the biogeochemical processes that control As mobility in wetland ecosystems were inferred. Based on factor analysis and cluster analysis, the vertical distributions of the redox zones in S2 and S5 were classified as oxidizing, transitional, and reducing zones, respectively. The mineralogical characteristics showed that adsorption and desorption are the major processes which control As retention in the surface sediment under cyclic aerobic/anaerobic conditions. Aqueous As and Fe were restrained because of oxidation, whereas aqueous Fe precipitated as amorphous metal oxides (i.e., FeO, FeOOH, and Fe2O3). Subsequently, aqueous As was adsorbed onto the surfaces of Fe(hydr)oxides, resulting in a high solid As content in the oxidizing zone. The high aqueous As content in the boundary of the transitional and reducing zones was caused by the reductive dissolution of highly dissolved Fe compounds through the microbial respiration of organic matter (OM). In the reducing zone, As3+ can be constrained by the formation of FeS2 in sediment during bacterial sulfate reduction that is governed by the relative enrichment of the δ34S[SO4] and δ18S[SO4] values. Sulfur disproportionation and the redox of elemental sulfur (S0) are additional reaction paths that cause As cycling. Arsenic mobility in the Guandu wetland is primarily caused by the reductive dissolution of As-containing Fe-oxyhydroxides and the redox cycling of sulfate/sulfide, accompanied by the respiration of OM.
出版者： Kidlington: Elsevier B.V
出版日期： 2013-08-19
出處： Journal of hydrology (Amsterdam), 2013-08, Vol.498, p.274-286
資源來源： Elsevier ScienceDirect Journals
版權： 2013 Elsevier B.V.
版權： 2014 INIST-CNRS
識別號： ISSN: 0022-1694
識別號： EISSN: 1879-2707
識別號： DOI: 10.1016/j.jhydrol.2013.06.009
識別號： CODEN: JHYDA7 |
| 顯示於類別: | [土木工程學系 ] 期刊論文
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