TY - JOUR
T1 - Identifying the sources and processes of mercury in subtropical estuarine and ocean sediments using hg isotopic composition
AU - Yin, Runsheng
AU - Feng, Xinbin
AU - Chen, Baowei
AU - Zhang, Junjun
AU - Wang, Wenxiong
AU - Li, Xiangdong
PY - 2015/2/3
Y1 - 2015/2/3
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84965134894&partnerID=8YFLogxK
U2 - 10.1021/es504070y
DO - 10.1021/es504070y
M3 - Journal article
C2 - 25565343
SN - 0013-936X
VL - 49
SP - 1347
EP - 1355
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 3
ER -