Guizhou Key Laboratory for Mountainous Environmental Information and Ecological Protection, Guizhou Normal University, Guiyang, 550001, PR China; College of Chemistry and Material, Guizhou Normal University, Guiyang, 550001, PR China.
Guizhou Key Laboratory for Mountainous Environmental Information and Ecological Protection, Guizhou Normal University, Guiyang, 550001, PR China.
Chemosphere. 2020 Sep;254:126828. doi: 10.1016/j.chemosphere.2020.126828. Epub 2020 Apr 18.
Spatial distribution characteristics of heavy metal (Cd, Pb, Cr, Cu, Zn, and Hg) contents and their ecological risks in the farmland along the shoreline of the Caohai wetland were investigated. Incubation experiments were also conducted to characterize the emission of heavy metals across soil-water interface if the farmland was reclaimed to wetland. The results showed that spatial distribution characteristics of these heavy metal contents were significantly different. Concentrations of Cd, Zn, and Hg were higher than the corresponding geochemical background levels. Ecological risk assessment suggested that the farmland along the shoreline of Caohai wetland were characterized by non-pollution or slight pollution of Pb, Cr, and Cu, moderate pollution of Cd, slight to moderate pollution of Hg, and slight pollution of Zn. Emission rates of Cd, Zn, and Hg across soil/sediment-water interface first increased, then decreased and finally reached equilibrium after the farmland soil was submersed. The contribution-rates of Cd, Zn, and Hg transferring from sediment to overlying water were calculated to be 12.7%, 14.8%, and 10.4%, respectively. We conclude that environmental issues caused by heavy metals, especially by Cd, Zn, and Hg, in the farmland along the shoreline of the Caohai wetland should be paid great attention.
研究了草海湿地岸线农田土壤中重金属（Cd、Pb、Cr、Cu、Zn 和 Hg）含量的空间分布特征及其生态风险。还进行了孵育实验，以表征如果将农田开垦为湿地，重金属通过土壤-水界面的排放情况。结果表明，这些重金属含量的空间分布特征存在显著差异。Cd、Zn 和 Hg 的浓度高于相应的地球化学背景水平。生态风险评估表明，草海湿地岸线农田土壤中 Pb、Cr 和 Cu 为无污染或轻度污染，Cd 为中度污染，Hg 为轻度至中度污染，Zn 为轻度污染。农田土壤被淹没后，Cd、Zn 和 Hg 从土壤/沉积物-水界面的排放速率先增加后减少，最后达到平衡。计算得出 Cd、Zn 和 Hg 从沉积物向覆盖水迁移的贡献率分别为 12.7%、14.8%和 10.4%。我们得出结论，应高度关注草海湿地岸线农田土壤中重金属（尤其是 Cd、Zn 和 Hg）引起的环境问题。
