1. School of Environmental Studies, China University of Geosciences, Wuhan 430078, China
2. Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
3. College of Environmental Science & Engineering, Guilin University of Technology, Guilin, China
4. Department of Earth Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
5. School of Environment, Beijing Normal University, Beijing, China