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膨润土联合磷酸氢二铵原位钝化修复汞污染土壤田间试验

谢园艳1,2,冯新斌1**,王建旭1   

  1. (1中国科学院地球化学研究所环境地球化学国家重点实验室, 贵阳 550002; 2中国科学院大学, 北京 100049)
  • 出版日期:2014-07-10 发布日期:2014-07-10

Insitu immobilization of mercury in soil using bentonite and diammonium phosphate from a field study.

XIE Yuan-yan1,2, FENG Xin-bin1**, WANG Jian-xu1   

  1. (1State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China; 2University of Chinese Academy of Sciences, Beijing 100049, China)
  • Online:2014-07-10 Published:2014-07-10

摘要:

以贵州万山汞矿区污染农田为试验田,研究添加膨润土、磷酸氢二铵、膨润土+磷酸氢二铵混施对土壤中汞的形态分布以及四季菜心的产量和汞含量的影响。结果表明,与对照土壤相比,添加膨润土、磷酸氢二铵、膨润土+磷酸氢二铵混施都能增加四季菜心地上部分和根系的干重,而且膨润土+磷酸氢二铵混施处理的四季菜心可食部分和根系生物量最大,分别增加4.7和4.8倍。与对照相比,膨润土+磷酸氢二铵混施能显著降低四季菜心地上部分和根系汞含量,其他处理无明显降低趋势。土壤中添加3%膨润土+0.5%磷酸氢二铵的混施处理四季菜心中汞含量最低。通过分析修复前后土壤汞的形态变化特征发现,膨润土+磷酸氢二铵混施能显著降低土壤中的有效态汞(溶解态与可交换态和特殊吸附态汞)和铁锰氧化态汞含量,而有机结合态汞和残渣态汞含量无显著变化。本研究结果可为汞污染土壤修复提供一定技术指导。

 

关键词: 水解酶, 有机碳含量, 温带森林, 海拔梯度, 氧化还原酶

Abstract: The single and combined effects of bentonite and diammonium phosphate additions on the distribution of fractionated Hg in soil and flowering cabbage grown in mercury (Hg) enriched soil were investigated under field conditions at Wanshan mercury mine in Guizhou Province. The results showed that the applications of bentonite, diammonium phosphate, and their mixture increased the dry biomass of the root and shoot of flowering cabbages compared with the control. Especially, the combined treatment resulted in a significant boost of root and shoot dry biomass (4.7 and 4.8 times higher respectively compared to the control). In this combined treatment case, the biomass Hg content was also significantly lower than the control, while this effect was insignificant in the single compound treatments. The flowering cabbages receiving the treatment of 3% bentonite and 0.5% diammonium phosphate had the lowest Hg content in various tissues. Concerning the combined treatments, chemical analysis of Hg fractions present in soil before and after the remediation period indicated a significant decrease in bioavailable Hg (soluble and exchangeable, specifically sorbed fractions) and Fe/Mnoxide bound Hg content, while the contents of the organic bound and residual Hg fractions were relatively stable. The results from this study may provide new insights and useful information for the remediation of Hg contaminated soil.

Key words: organic carbon content, altitude gradient, temperate forest, oxidoreductase, hydrolase