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| Characteristics of Cr(Ⅵ) leaching in oxisol under simulated column experiment |
| Received:December 08, 2015 |
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| KeyWord:hexavalent chromium;latosol;leaching |
| Author Name | Affiliation | E-mail | | ZHONG Lai-yuan | Department of Resources and Environmental Sciences, College of Agriculture, Guangdong Ocean University, Zhanjiang 524088, China | | | ZHONG Yan-bin | Department of Resources and Environmental Sciences, College of Agriculture, Guangdong Ocean University, Zhanjiang 524088, China | | | YANG Jie-wen | Department of Resources and Environmental Sciences, College of Agriculture, Guangdong Ocean University, Zhanjiang 524088, China | jw_yang@126.com |
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| Abstract: |
| Understanding Cr(Ⅵ) leaching is important for assessments of groundwater and health risk of soil Cr. A simulated soil column experiment was conducted to examine the effects of organic fertilizer and coexisting ions on the release of soil Cr(Ⅵ) under simulated acid rain condition, using an oxisol. At Cr(Ⅵ) inputs less than 240 mg·kg-1, concentrations of Cr(Ⅵ) in leachate were below the detection limit of diphenylcarbazide colorimetric spectrophotometic method used in this study, which was attributed to the large adsorption capacity of Fe-rich soil for Cr(Ⅵ). In amendment of organic fertilizer, leaching of Cr(Ⅵ) was enhanced at the early stage, but reduced at the later stage, in comparison with the control, partially ascribed to the reduction of Cr(Ⅵ) to less mobile Cr(Ⅲ) on the soil surface by organic fertilizer. At the coexistence of Cu(Ⅱ), the mobility of Cr(Ⅵ) in the soil was inhibited because soil surface ζ-potential became more positive under the presence of Cu(Ⅱ) and Cr(Ⅵ) adsorption was then promoted. On the contrary, more Cr(Ⅵ) was leached out of the soil in the presence of phosphate because of competition for surface adsorption sites. Acidic rain increased the release of Cr(Ⅵ) in the soil during the initial period but decreased as the experiment prolonged. Overall, this study would be helpful for us to understand the mobility of Cr(Ⅵ) in oxisol and to assess the environmental risk of Cr(Ⅵ)-polluted soil. |
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