Effect of Submerged Condition on Chemical Form of Cd in Soil of Three Gorges Reservoir Area
JI Fang-ying,WANG Tu-jin,YE Jiang-yu,LI Si and CAO Lin
DOI:10.11835/j.issn.1674-4764.2012.02.019
Received ,Revised , Accepted , Available online July 01, 2015
Volume ,2012,Pages 115-120
- Abstract
Purple soil and yellow soil of Three Gorges Reservoir Area were submerged and incubated under a nitrogen atmosphere to study the effect of redox process on chemical form of Cd. It is shown that the pH and Eh decrease in the redox process. With the transition of soil redox condition, the content of CEC increases to 1753 cmol·kg -1 for purple soil and 2794 cmol·kg -1 for yellow soil, and the content of Fe (II) increases to 3 15630 mg·kg -1 for yellow soil and 44656mg·kg -1 for purple soil. The soluble Cd concentration declines after submergence for the purple soil and yellow soil, and 99.9% of soluble Cd is absorbed by soils. Chemical form of Cd in soil is significant correlated with the physical-chemical indexes of soil. In the process of redox process, part of Exc-Cd (exchanged fraction) transforms to Carb-Cd (carbonated fraction) and Oxide-Cd (oxide-bound fraction), and the content of Exc-Cd decreases to 456 mg·kg -1 for purple soil and 102 mg·kg -1 for yellow soil. The stability of Cd in yellow soil is higher than that in purple soil.