Isotopic evidence for distinct sources of mercury in lake waters and sediments

	Isotopic evidence for distinct sources of mercury in lake waters and sediments
	Jiubin Chen; Holger Hintelmann; Wang Zheng; Xinbin Feng; Hongming Cai; Zhuhong Wang; Shengliu Yuan; Zhongwei Wang
	2016
发表期刊	Chemical Geology
卷号	426 期号:1 页码:33-44
摘要	Lakes are important ecosystems where mercury (Hg) may undergo extensive methylation and bioaccumulation in the aquatic food web. It is thus crucial to understand the sources of Hg in lake systems. Mercury isotope composition is a powerful tracer of its sources in the environment However, previous studies on Hg isotope compositions in lake systems mainly focus on the aquatic organism and sediments, whereas lake water that provides the nutrients for the bottom of aquatic food chain has received much less attention. Here we report Hg isotope compositions in surface water and sediments of 8 freshwater lakes in Ontario, Canada. We determined significantly positive Delta Hg-199 and Delta Hg-200 values in surface water of all lakes, which are similar to previously reported isotope signature of local atmospheric precipitation. In contrast, the isotope compositions of lake sediments show predominantly negative Delta Hg-199 and negligible Delta Hg-200 values that are similar to atmospheric elemental Hg(0) and terrestrial soils and plants. We conclude that the source of Hg in lake surface water is likely dominated by direct atmospheric precipitation, while the Hg in lake sediments is primarily derived from watershed inputs of terrestrial particles. The concurrent odd Hg isotope anomalies in surface waters suggest that methylmercury (MeHg) from the watershed wetland, together with Hg(II) derived from the catchment weathering is likely another Hg source to lake waters besides atmospheric deposition. We suggest that the different Hg sources and isotope compositions between lake water and sediments would result in different isotope signatures for MeHg that is produced in water column and in sediments. Therefore, our study not only elucidates the sources of Hg to lake systems, but also has implications in distinguishing between different McHg sources and in tracing the bioaccumulation of McHg in aquatic organism.
学科领域	环境地球化学
收录类别	SCI
语种	英语
文献类型	期刊论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/6149
专题	环境地球化学国家重点实验室_环境地球化学国家重点实验室_期刊论文环境地球化学国家重点实验室
推荐引用方式 GB/T 7714	Jiubin Chen,Holger Hintelmann,Wang Zheng,et al. Isotopic evidence for distinct sources of mercury in lake waters and sediments[J]. Chemical Geology,2016,426(1):33-44.
APA	Jiubin Chen.,Holger Hintelmann.,Wang Zheng.,Xinbin Feng.,Hongming Cai.,...&Zhongwei Wang.(2016).Isotopic evidence for distinct sources of mercury in lake waters and sediments.Chemical Geology,426(1),33-44.
MLA	Jiubin Chen,et al."Isotopic evidence for distinct sources of mercury in lake waters and sediments".Chemical Geology 426.1(2016):33-44.

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