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The solid-phase partitioning of arsenic in unconsolidated sediments of the Mekong Delta, Vietnam and its modes of release under various conditions
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| Title: | The solid-phase partitioning of arsenic in unconsolidated sediments of the Mekong Delta, Vietnam and its modes of release under various conditions |
| Authors: | Dang Thuong Huyen Browse this author | | Tabelin, Carlito Baltazar Browse this author | | Huynh Minh Thuan Browse this author | | Dang Hai Dang Browse this author | | Phan Thi Truong Browse this author | | Vongphuthone, Banthasith Browse this author | | Kobayashi, Masato Browse this author | | Igarashi, Toshifumi Browse this author →KAKEN DB |
| Keywords: | Vietnamese mekong delta | | Arsenic | | Leaching | | Sequential extraction | | Pyrite | | Phyllosilicates |
| Issue Date: | Oct-2019 |
| Publisher: | Elsevier |
| Journal Title: | Chemosphere |
| Volume: | 233 |
| Start Page: | 512 |
| End Page: | 523 |
| Publisher DOI: | 10.1016/j.chemosphere.2019.05.235 |
| Abstract: | Arsenic (As) contamination of the groundwater in the Mekong Delta is a serious problem affecting millions of people who rely on this important resource for drinking and agriculture. In this study, borehole cores up to a depth of 40 m were collected in the Vietnamese-side of the delta, and the solid-phase partitioning of As with depth was investigated to understand the factors and processes controlling the release of this toxic element under oxic, acidic and reducing conditions. The results showed that in most of the sediments, substantial amounts of As are partitioned with exchangeable phases that are easily released into solution. Two borehole cores obtained between the Hau and Tien Rivers also had significantly high As partitioned with organic/sulfide phases and one of these cores had abundant As-bearing pyrite in 1-m thick peat layers. Leaching experiments in deionized (DI) water coupled with principal component analysis suggest that As release was controlled by sorption-desorption reactions with clays/phyllosilicates (i.e., kaolinite, muscovite and clinochlore), proton-promoted dissolution of iron-oxyhydroxides, and oxidation of pyrite/organic matter. The mobility of As was further promoted under acidic conditions in the presence of chloride (Cl-), which suggests that seasonal drying/flooding episodes generating acid sulfate soils, as well as salt water intrusion due to excessive groundwater abstraction may exacerbate this problem in the future. |
| Rights: | © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/ | | https://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/82845 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 五十嵐 敏文
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