1. School of Chemistry and Environmental Engineering, China University of Mining and Technology, Beijing, 11 Xueyuan Road, Beijing 100083, P. R. China
2. Xi’an Geological Survey Center of China Geological Survey, Xi’an Zhongdi Environmental Technology Co., Ltd. 438, Youyi East Road, Xi’an, Shanxi 710054, P. R. China
3. Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18, Shuangqing Road, Beijing 100085, P. R. China
4. School of Environment, Tsinghua University, 30, Shuangqing Road, Beijing 100084, P. R. China