1. Key Laboratory of Water Environment Evolution and Pollution Control in Three Gorges Reservoir, School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404130, P. R. China
2. School of Civil and Environmental Engineering, Ningbo University, Ningbo 315211, P. R. China
3. Tri-Y Environmental Research, 2655 Lillooet St., Vancouver V5M 4P7, BC, Canada