| Title: | Geochemical controls on the distribution of total mercury and methylmercury in sediments and porewater from the Yangtze River Estuary to the East China Sea |
| Author(s): | Cao F; Yang S; Yin D; Wang R; |
| Address: | "Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China. State Key Laboratory of Marine Geology, School of Ocean and Earth Science, Tongji University, Shanghai 200092, PR China. Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China. Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China. Electronic address: wangr@tongji.edu.cn" |
| DOI: | 10.1016/j.scitotenv.2023.164737 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "A comprehensive investigation was conducted to explore the distributions of total mercury (THg) and methylmercury (MeHg) in sediments and porewater along a typical transect from the Yangtze River Estuary (YRE) to the East China Sea (ECS) open shelf. THg concentrations in the surface sediments exhibited large variations across sites, higher in the estuary mixing region, especially within the turbidity maximum zone (TMZ). The spatial and vertical distributions (0-20 cm) of THg in sediments were highly controlled by sediment grain size and total organic carbon (TOC), due to the strong binding between Hg and fine-grained sediments that enriched with organic matter. In contrast, MeHg concentrations in surface sediments were higher in the estuary mixing region and the ECS open shelf than in the river channel, with remarkably higher MeHg/THg ratios in sediments and porewater at the open shelf sites, identified as the regional hotspots of the net in situ MeHg production. Considering the large gradients of physiochemical properties of sediments, porewater and the overlying water, the results of this study suggested that the higher net Hg methylation potential in the open shelf region was largely attributed to the lower acid volatile sulfide, lower TOC and higher salinity, which facilitated the partitioning of inorganic Hg into porewater that highly bioavailable for Hg-methylation bacteria. Moreover, the estimated diffusive fluxes of MeHg at the sediment-water interface were positive at all the tested sites, and pronouncedly higher within the TMZ (driven by the higher THg loading and higher porosity) that requires special attention" |
| Keywords: | "*Mercury/analysis *Methylmercury Compounds/analysis Rivers/chemistry Estuaries *Water Pollutants, Chemical/analysis Geologic Sediments/chemistry Environmental Monitoring/methods Water China Estuary Mercury Methylation Organic matter Sulfide;" |
| Notes: | "PubMed-not-MEDLINECao, Feng Yang, Shouye Yin, Daqiang Wang, Rui eng Netherlands 2023/06/11 Sci Total Environ. 2023 Sep 20; 892:164737. doi: 10.1016/j.scitotenv.2023.164737. Epub 2023 Jun 8" |
