Westerlies-driven transboundary transport of atmospheric mercury to the north-central Tibetan Plateau

Shiwei Sun; Ming Ma; Junming Guo; Xiaobo He; Xiufeng Yin; Tao Sun; Qianggong Zhang; Shichang Kang

doi:10.1016/j.scitotenv.2024.173135

Westerlies-driven transboundary transport of atmospheric mercury to the north-central Tibetan Plateau

Sci Total Environ. 2024 Jul 1:932:173135. doi: 10.1016/j.scitotenv.2024.173135. Epub 2024 May 9.

Authors

Shiwei Sun¹, Ming Ma², Junming Guo¹, Xiaobo He³, Xiufeng Yin¹, Tao Sun⁴, Qianggong Zhang⁵, Shichang Kang⁶

Affiliations

¹ State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China.
² College of Resources and Environment, Southwest University, Chongqing 400715, China.
³ State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Tanggula Cryosphere and Environment Observation Station, State Key Laboratory of Cryospheric Science, Lanzhou 730000, China.
⁴ School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China.
⁵ State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, CAS, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
⁶ State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: shichang.kang@lzb.ac.cn.

PMID: 38734088
DOI: 10.1016/j.scitotenv.2024.173135

Abstract

The transboundary mercury (Hg) pollution has caused adverse effects on fragile ecosystems of the Tibetan Plateau (TP). Yet, knowledge of transport paths and source regions of atmospheric Hg on the inland TP remains poor. Continuous measurements of atmospheric total gaseous mercury (TGM) were conducted in the central TP (Tanggula station, 5100 m a.s.l., June-October). Atmospheric TGM level at Tanggula station (1.90 ± 0.30 ng m^-3) was higher than the background level in the Northern Hemisphere. The identified high-potential source regions of atmospheric TGM were primarily located in the northern South Asia region. TGM concentrations were lower during the Indian summer monsoon (ISM)-dominant period (1.81 ± 0.25 ng m^-3) than those of the westerly-receding period (2.18 ± 0.40 ng m^-3) and westerly-intensifying period (1.91 ± 0.26 ng m^-3), contrary to the seasonal pattern in southern TP. The distinct TGM minima during the ISM-dominant period indicated lesser importance of ISM-transported Hg to Tanggula station located in the northern boundary of ISM intrusion, compared to stations in proximity to South and Southeast Asia source regions. Instead, from the ISM-dominant period to the westerly-intensifying period, TGM concentrations showed an increasing trend as westerlies intensified, indicating the key role of westerlies in transboundary transport of atmospheric Hg to the inland TP.

Keywords: Atmospheric total gaseous mercury (TGM); Source region; Tanggula station; Transport path.