1. State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, P. R. China
2. Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
3. Monitoring Centre of Pearl River Valley Aquatic Environment, Scientific Institute of Pearl River Water Resources Protection, Guangzhou 510611, China
4. Soil and Water Science Department, University of Florida, Gainesville, Florida 32611, United States