1. School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, P. R. China
2. Laboratoire Sols et Environnement, INRA, Universitéde Lorraine, BP 172, 2 avenue de la forê t de Haye, Vandoeuvre-lè s-Nancy Cedex, France
3. Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, P. R. China