1. State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, P.O. Box 2871, Beijing 100085, China
2. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100039, People’s Republic of China
3. Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden