Dynamics and diagenesis of trace metals in sediments of the Changjiang Estuary

Liqin Duan; Jinming Song; Xianmeng Liang; Meiling Yin; Huamao Yuan; Xuegang Li; Chengzhe Ren; Bu Zhou; Xuming Kang; Xuebo Yin

doi:10.1016/j.scitotenv.2019.04.190

Dynamics and diagenesis of trace metals in sediments of the Changjiang Estuary

Sci Total Environ. 2019 Jul 20:675:247-259. doi: 10.1016/j.scitotenv.2019.04.190. Epub 2019 Apr 16.

Authors

Liqin Duan¹, Jinming Song², Xianmeng Liang³, Meiling Yin³, Huamao Yuan⁴, Xuegang Li⁴, Chengzhe Ren³, Bu Zhou⁵, Xuming Kang⁶, Xuebo Yin⁷

Affiliations

¹ CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China. Electronic address: duanliqin@qdio.ac.cn.
² CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China. Electronic address: jmsong@qdio.ac.cn.
³ CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
⁴ CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China.
⁵ CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China.
⁶ Key Laboratory of Testing and Evaluation for Aquatic Product Safety and Quality, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, PR China.
⁷ Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China; CAS Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China.

PMID: 31030132
DOI: 10.1016/j.scitotenv.2019.04.190

Abstract

The seasonal dynamics and diagenesis of trace metals at two contrasting coastal sites were studied to determine the mechanism that drove the diffusive release of trace metals from sediments in the Changjiang Estuary. Porewater trace metal concentrations were 53.4-4829 nM for Zn, 11.0-344 nM for Cu, 7.75-221 nM for Cr, 2.71-61.1 nM for Co, 0.822-42.7 nM for Pb and 0.037-4.22 nM for Cd. The concentrations and profiles of trace metals in the porewater and solid phase displayed obvious regional and seasonal variations. This variation was mainly reflected in the surface layer and the depth of the suboxic and anoxic layers. Regionally, surface porewater trace metal concentrations in the seasonal hypoxic region were higher than those in the aerobic region due to changes in the redox conditions being beneficial to the release of trace metals. Seasonally, surface porewater trace metal concentrations decreased in summer compared to spring due to their removal by forming metal sulfides in summer. Solid profiles of the trace metals supported their dynamic variations in the porewater. The partition coefficient suggested that the formation of Fe/Mn (hydr)oxides was effective for the removal of trace metal in oxidizing condition, while the formation of sulfides was conducive to the removal of trace metals in reducing condition. The combination of porewater with solid phase data suggested that the dynamics of Cu, Zn, Cr and Co were mainly controlled by Fe and Mn diagenesis, the dynamics of Cd were affected by S cycling, and the dynamics of Pb were disturbed by anthropogenic inputs and benthic organism activities. Estimation of benthic fluxes indicated that sediments were an important source of trace metals in the water column. The contributions of trace metals by sediments to the water column of the Changjiang Estuary were only one order of magnitude lower than those by riverine fluxes.

Keywords: Benthic fluxes; Early diagenesis; Porewater; Seasonal cycling; The Changjiang Estuary; Trace metals.