1 State Key Laboratory of Environmental Geochemistry Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, People's Republic of China. liping@mail.gyig.ac.cn.
2 Department of Geosciences, University of Texas at Dallas, Richardson, TX, USA.
3 College of Geoscience and Survey Engineering, China University of Mining and Technology (Beijing), Beijing, China.
4 International Network for Environment and Health, School of Geography and Archaeology & Ryan Institute, National University of Ireland, Galway, Ireland.