1. Physical Environment Group, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, P. R. China;
2. University of Chinese Academy of Sciences, Beijing, P. R. China;
3. Xiamen Key Laboratory of Physical Environment, Xiamen, P. R. China;
4. Environmental Bioelectrochemistry Center, Fujian Agriculture and Forestry University, Fuzhou, P. R. China