BGC-01 Mercury biogeochemical cycling in the ocean
Mass Budget of Mercury (Hg) in the Seawater of Eastern China Marginal Seas: Importance of the Sediment-water Transport Processes
Lufeng Chen* , Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, China
Chang Liu, Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China
Yongguang Yin, Laboratory of Environmental Nanotechnology and Health Effect and State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
Guangliang Liu, Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
Yanbin Li, Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China
Yong Cai, Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA

The Eastern China Marginal Seas (ECMS) have been facing a variety of environmental problems, including mercury (Hg) pollution. Although several previous studies have been focused on mass balance of Hg in the ECMS, the contribution of Hg transport at the sediment-water interface remains unclear. This study was aimed to access and quantify the importance of sediment-water transport processes in Hg cycling. Significantly positive correlations were observed between Hg concentrations in the overlying and bottom water and the diffusion rates of Hg from sediment to the water. Approximately 2-3 times higher of THg concentrations in the entire water column were observed in a winter cruise with strong waves which was supposed to strengthen the resuspension process. The mass budget of Hg in the ECMS further showed that diffusion and resuspension processes accounted for approximate 46%, 60%, and 16% of total input Hg in the BS, YS, and ECS, respectively. These results suggest that the sediment-water transport processes play an important role in Hg cycling in the ECMS. As an important ‘pool’ of Hg in the ECMS, the transport of Hg at the sediment-water interface may affect the long-term risk assessment of Hg in these systems.