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Seasonal effects of natural attenuation on drainage contamination from artisanal gold mining, Cambodia: Implication for passive treatment
| Title: | Seasonal effects of natural attenuation on drainage contamination from artisanal gold mining, Cambodia: Implication for passive treatment |
| Authors: | Tum, Sereyroith Browse this author | | Toda, Kanako Browse this author | | Matsui, Tatsuya Browse this author | | Kikuchi, Ryosuke Browse this author →KAKEN DB | | Kong, Sitha Browse this author | | Meas, Panha Browse this author | | Ear, Unsovath Browse this author | | Ohtomo, Yoko Browse this author →KAKEN DB | | Otake, Tsubasa Browse this author →KAKEN DB | | Sato, Tsutomu Browse this author →KAKEN DB |
| Keywords: | Artisanal mining | | Natural attenuation | | Passive treatment | | Seasonal dynamics | | Schwertmannite | | Arsenic |
| Issue Date: | 1-Feb-2022 |
| Publisher: | Elsevier |
| Journal Title: | Science of the total environment |
| Volume: | 806 |
| Issue: | Part 1 |
| Start Page: | 150398 |
| Publisher DOI: | 10.1016/j.scitotenv.2021.150398 |
| Abstract: | In Mondulkiri province, Cambodia, artisanal gold miners dump tailings and wastewater from gold processing into a tributary of the Prek Te River. In the rainy season, heavy metal concentrations in the tributary decrease below the WHO drinking water standard levels through natural attenuation; however, this does not occur in the dry season. To further understand the natural attenuation mechanism, detailed analyses of the wastewater from tail-ing and tributary water, tributary sediments, waste rock, and ore minerals were undertaken in both seasons. The high concentration of dissolved Fe in the contaminated tributary plays a significant role in As removal during the rainy season, whereas other elements such as Ni, Se, and Cu concentration decrease due to dilution. Schwertmannite formation, controlled by iron-oxidizing bacteria, was only found at the bottom of the tributary during the rainy season. In the dry season, As, Ni, Se, and Cu concentrations remained at their original levels be-cause there was no formation of schwertmannite or dilution by rainwater. The existing schwertmannite also starts to dissolve as the pH decreases. Seasonal dynamics cause the failure of natural attenuation; thus, methods for maintaining its effectiveness in the dry season are needed. In addition, geochemical modeling was conducted to determine the significant roles of schwertmannite formation and dilution of rainwater in the tributary. Schwertmannite is a potential adsorbent for As removal from drainage. However, dilution provided indirect and direct impacts on the tributary, such as increasing the pH and diluting the concentration of toxic elements. |
| Rights: | © <2022>. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Type: | article |
| URI: | http://hdl.handle.net/2115/83053 |
| 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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