title: Environmental evolution records reflected by radionuclides in the sediment of coastal wetlands: A case study in the Yellow River Estuary wetland.
abstract: Vertical profiles of environmental radionuclides (210Pb,137Cs,238U,232Th,226Ra and40K) in a sediment core (Y1) of the Yellow River Estuary wetland were investigated to assess whether environmental evolutions in the coastal wetland could be recorded by the distributions of radionuclides. Based on210Pb and137Cs dating, the average sedimentation rate of core Y1 was estimated to be 1.0 cm y-1. Vertical distributions of natural radionuclides (238U,232Th,226Ra and40K) changed dramatically, reflecting great changes in sediment input. Concentrations of238U,232Th,226Ra and40K all had significant positive relationships with organic matter and clay content, but their distributions were determined by different factors. Factor analysis showed that238U was determined by the river sediment input while226Ra was mainly affected by the seawater erosion. Environmental changes such as river channel migrations and sediment discharge variations could always cause changes in the concentrations of radionuclides. High concentrations of238U and226Ra were consistent with high accretion rate. Frequent seawater intrusion decreased the concentration of226Ra significantly. The value of238U/226Ra tended to be higher when the sedimentation rate was low and tide intrusion was frequent. In summary, environmental evolutions in the estuary coastal wetland could be recorded by the vertical profiles of natural radionuclides.
authors.affiliation: Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology (IO), Chinese Academy of Sciences (CAS), Qingdao 266071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Qidong
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology (IO), Chinese Academy of Sciences (CAS), Qingdao 266071, PR China. Electronic address: jmsong@qdio.ac.cn.
authors.forename: Jinming
authors.initials: J
authors.lastname: Song
authors.affiliation: Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology (IO), Chinese Academy of Sciences (CAS), Qingdao 266071, PR China.
authors.forename: Xuegang
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology (IO), Chinese Academy of Sciences (CAS), Qingdao 266071, PR China.
authors.forename: Huamao
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology (IO), Chinese Academy of Sciences (CAS), Qingdao 266071, PR China.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.affiliation: Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology (IO), Chinese Academy of Sciences (CAS), Qingdao 266071, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Cao
mesh_terms: D063366:Estuaries; D019015:Geologic Sediments; D011834:Radiation Monitoring; D045483:Rivers; D014878:Water Pollution, Radioactive / Q000706:statistics & numerical data*; D053833:Wetlands
keywords: Environmental evolution; Radionuclides; Vertical distribution; Wetland sediments; Yellow River Estuary