Effect of Zero-Valent Iron Application on Cadmium Uptake in Rice Plants Grown in Cadmium-Contaminated Soils

ABSTRACT

Cadmium (Cd) contamination in soils is a serious problem for crop production in the world. Zero-valent iron [Fe (0)] is a reactive material with reducing power capable of stabilizing toxic elements in a solution. In the present study, we examined the effect of zero-valent iron [Fe (0)] application on Cd accumulation in rice plants growing in Cd-contaminated paddy soils. The application of 1.0 and 0.5 mg Fe (0) per 100 g soils significantly reduced the Cd concentration in seeds and leaves by less than 10% and 20% of those without Fe (0) application, respectively. The form of Cd in soil was determined by sequential extraction. The Fe (0) application increased the free-oxides-occluded (less available) Cd content, and decreased the exchangeable and iron-manganese-oxides-bound (more available) Cd content, in Cd-contaminated soils. Thus, this study clearly showed that the application of Fe (0) is a promising approach for remediation of Cd-contaminated paddy soils.

Keywords:

• cadmium-contaminated soils
• Oryza sativa L.
• reducing power
• sequential extraction method
• zero-valent iron

ACKNOWLEDGMENTS

This study was supported financially by a Grant-in-Aid for Scientific Research (No. 16780043) from the Ministry of Education, Culture, Sports, Science, and Technology, and by a Steel Industry Foundation for the Advancement of Environmental Protection Technology.