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| Influence of Wetting-Drying and Flooding Water Managements on Forms and Availability of Arsenic and Antimony in Polluted Soils |
| Received:April 08, 2015 |
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| KeyWord:water management;Fe-oxides;in-situ analysis;availability |
| Author Name | Affiliation | E-mail | | CUI Xiao-dan | Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | WANG Yu-jun | Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | yjwang@issas.ac.cn | | ZHOU Dong-mei | Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | |
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| Abstract: |
| Xikuangshan is the world's largest antimony(Sb) mine and the surrounding soils are heavily contaminated with Sb, usually along with arsenic(As) as an associated pollutant. In this study, traditional chemical extraction methods and in-situ synchrotron-based techniques such as μ-XRF and μ-XANES were used to reveal forms and availability of As and Sb in the soil from Xikuangshan area. An indoor experiment was also conducted to investigate the effects of water managements(flooding and wetting-drying) on forms and availability of As and Sb. μ-XRF and μ-XANES analyses indicated that in the tested soil, arsenic mainly existed in penta-valent form and the As distribution was significantly correlated with soil Fe, Ca, and S(correlation coefficients being 0.15, 0.32, and 0.38, respectively, P<0.05). Compared with alternative wetting-drying, flooding treatment resulted in a large amount of As and Sb release to soil solutions, with 71.7%~4409% increase of As and 3.53%~77.1% rise of Sb in the soil solutions, respectively. Furthermore, flooding treatment caused non-crystalline Fe oxides to increase by 13.8%, leading to increases in content of As and Sb associated with Fe oxides by 17.6% and 32.33%, respectively. A linear correlation was found of Fe-As and Fe-Sb with non-crystalline Fe oxides(r2=0.75 and r2=0.70, respectively, P<0.05), indicating a stronger influence of non-crystalline Fe oxides on As and Sb adsorption. Increased surface areas during transition from crystalline Fe oxides to non-crystalline Fe oxides promoted adsorption, and thus reduced the mobility and availability of As and Sb. However, enhancement of reductive dissolution of Fe/Mn oxides under flooding condition resulted in more As and Sb released to solution. Therefore, alternative wetting-drying treatment increased the adsorption and fixation of As and Sb, while flooding treatment generally increased their mobility and availability. |
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