Tracking the multiple Hg sources in sediments in a typical river-lake basin by isotope compositions and mixing models

Lulu Mao; Wenbo Ren; Xitao Liu; Mengchang He; Chunye Lin; Ying Zhong; Yang Tang; Wei Ouyang

doi:10.1016/j.jhazmat.2023.132166

Tracking the multiple Hg sources in sediments in a typical river-lake basin by isotope compositions and mixing models

J Hazard Mater. 2023 Oct 5:459:132166. doi: 10.1016/j.jhazmat.2023.132166. Epub 2023 Jul 27.

Authors

Lulu Mao¹, Wenbo Ren¹, Xitao Liu², Mengchang He¹, Chunye Lin¹, Ying Zhong³, Yang Tang³, Wei Ouyang⁴

Affiliations

¹ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
² State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China. Electronic address: liuxt@bnu.edu.cn.
³ State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081 Guiyang, China.
⁴ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China; Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai 519087, China.

PMID: 37531762
DOI: 10.1016/j.jhazmat.2023.132166

Abstract

In this study, total mercury (THg) contents and Hg isotope compositions in sediments were investigated in the Lianxi River, Zijiang River and South Dongting Lake to identify and quantify multiple Hg sources and evaluate the Hg environmental processes. The THg contents, δ²⁰²Hg and Δ¹⁹⁹Hg values in sediments were 48.22 ∼ 4284.32 µg/kg, - 1.33 ∼ 0.04‰ and - 0.25 ∼ 0.03‰, respectively. Relatively distinct Hg isotope characteristics of sediments were presented in the Lianxi River, Zijiang River and South Dongting Lake, indicating the dominant Hg sources considerably varied in these regions. Source apportionment based on MixSIAR proved that Hg in sediments mainly originated from industrial activities, and the ternary mixing model concluded non-ferrous metal smelting was the dominant industrial Hg contributor in the Lianxi River. Compared with the Lianxi River, the relative contribution of Hg in sediments from industrial activities significantly decreased, while the relative contributions of Hg from background releases significantly increased in the Zijiang River and South Dongting Lake. Nonetheless, the contribution of industrial Hg in this study area deserves more attention. These results are conducive to further manage Hg pollution.

Keywords: Bayesian stable isotope mixing model; Hg isotope signatures; Source apportionment; Zijiang River basin.