1. College
of Environment and Resources, Inner Mongolia University, Huhhot 010021, China
2. Institute of Environmental
Geology, Inner Mongolia University, Huhhot 010021, China
3. Department of Chemistry, University of Oslo, N-0315, Oslo, Norway
4. Forestry College, Inner Mongolia Agricultural University, Huhhot 010019, China
5. Tianjin Academy of Environmental Sciences, Tianjin, 300191, China