1. State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Science, Chinese Academy of Science, Beijing 100085, People's Republic of China.
2. The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Natural Resources & Environment, Beijing Forestry University, Beijing 100083, People's Republic of China.
3. State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Science, Chinese Academy of Science, Beijing 100085, P.R. China. Phone: +86-10-62849151; Fax: +86-10-62923558; E-mail: jhqu@mail.rcees.ac.cn