Identifying the sources and processes of mercury in subtropical estuarine and ocean sediments using hg isotopic composition

Runsheng Yin, Xinbin Feng, Baowei Chen, Junjun Zhang, Wenxiong Wang, Xiangdong Li

Research output: Journal article publicationJournal articleAcademic researchpeer-review

124 Citations (Scopus)

Abstract

The concentrations and isotopic compositions of mercury (Hg) in surface sediments of the Pearl River Estuary (PRE) and the South China Sea (SCS) were analyzed. The data revealed significant differences between the total Hg (THg) in fine-grained sediments collected from the PRE (8-251 μg kg-1) and those collected from the SCS (12-83 μg kg-1). Large spatial variations in Hg isotopic compositions were observed in the SCS (δ202Hg, from -2.82 to -2.10‰; Δ199Hg, from +0.21 to +0.45‰) and PRE (δ202Hg, from -2.80 to -0.68‰; Δ199Hg, from -0.15 to +0.16‰). The large positive Δ199Hg in the SCS indicated that a fraction of Hg has undergone Hg2+photoreduction processes prior to incorporation into the sediments. The relatively negative Δ199Hg values in the PRE indicated that photoreduction of Hg is not the primary route for the removal of Hg from the water column. The riverine input of fine particles played an important role in transporting Hg to the PRE sediments. In the deep ocean bed of the SCS, source-related signatures of Hg isotopes may have been altered by natural geochemical processes (e.g., Hg2+photoreduction and preferential adsorption processes). Using Hg isotope compositions, we estimate that river deliveries of Hg from industrial and urban sources and natural soils could be the main inputs of Hg to the PRE. However, the use of Hg isotopes as tracers in source attribution could be limited because of the isotope fractionation by natural processes in the SCS.
Original languageEnglish
Pages (from-to)1347-1355
Number of pages9
JournalEnvironmental Science and Technology
Volume49
Issue number3
DOIs
Publication statusPublished - 3 Feb 2015

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry

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