Notice of Retraction: Effects of Freeze/Thaw Cycles on Cd and Zn Form Transformation in the Phaiozem

Abstract

Freeze/thaw cycles (FTCs) is one of the important environment factors which can make the Cd and Zn forms (Tessier et al. sequential extraction methods) transformation. The investigations indicated that additional Cd exchangeable and organic matter binding forms in the phaiozem had negative linearity correlation with FTCs (p<;0.01), respectively. After 12 times of FTCs, the Cd exchangeable and organic matter binding forms decreased 4.42% and 8.40%, respectively, as compared with those of the Control Samples (CSs). Adversely, the Cd iron-manganese oxide binding and residual forms had positive linearity correlation with FTCs (p<;0.01), respectively. After 12 times of FTCs, the Cd iron-manganese oxide binding and residual forms increased 10.44% and 6.17% respectively, as compared with those of the CSs. It was induced that the Cd organic matter binding form could not only transform to the residual form, but also to the iron-manganese oxide binding form with the increase of FTCs. The form transformations of Zn were different from those of Cd because of its relatively high content in soil and special chemical characteristics. After 8 times of FTCs, the Zn exchangeable, iron-manganese oxide binding forms decreased 3.42% and 11.65% respectively, and then changed a little. Whereas, the Zn organic matter binding form increased firstly and then decreased gradually. After 12 times of FTCs, the Zn organic matter binding form and residual forms increased 3.42% and 18.84%, respectively. The correlations between all forms of Zn and FTCs followed quadratic functions, and their coefficients were between 0.947 and 0.999.