Dr. Hua Zhang received his Ph.D degree in Environmental Geochemistry from University of Chinese Academy of Sciences (former Graduate University of Chinese Academy of Sciences) and worked as a Distinguished Consultant on environmental policy at the Foreign Cooperation Center, Ministry of Environmental Protection (FECO-MEP) in China. He is now a Research Scientist at Norwegian Institute for Water Research (NIVA). His broad research interest includes environmental policy, biogeochemistry of trace elements (mercury and selenium) and human health risk assessment. His recent interests also includes the links between contaminant cycling and topography, climate change, land types, etc., by using a wide range of methods from simulation models, monitoring and survey data analyses, field work and laboratory experiments.

• Research Background.- Advances of Research on the Mechanisms of Selenium-Mercury Interactions and Health Risk Assessment.- Research Subject, Methods and Significance.- Overview of the Study Area (Wanshan).- Biogeochemical Cycles of Mercury in River System.- Biogeochemical Cycles of Selenium in River System.- Interaction of Mercury and Selenium in River System.- Biogeochemical Cycles of Mercury in Soil-Rice System.- Biogeochemical Cycles of Selenium in Soil-Rice System.- Interaction of Mercury and Selenium in Soil-Rice System.- Health Risk Assessment for Human Exposure to Mercury.- Health Risk Assessment for Human Exposure to Selenium.- Health Risk Assessment for Human Exposure to Mercury and Selenium Considering Selenium-Mercury Interactions.- Conclusions.- Research Needs and Future Outlook.