| 13 Mar 2026
Mercury dataset over the Third Pole
Abstract. The Tibetan Plateau and its surrounding regions, collectively known as the Third Pole, constitute one of Earth’s largest topographic and cryospheric features, playing a pivotal role in the cycling of trace elements at both regional and global scales. Mercury (Hg), a toxic heavy metal of global concern, has garnered increasing attention due to its detrimental effects on environmental and human health. Large-scale atmospheric circulation facilitates the long-range transport of atmospheric Hg pollutants, which can subsequently be deposited across the Third Pole. Over recent decades, the Atmospheric Pollution and Cryospheric Change (APCC) program has established and sustained an integrated monitoring network throughout this region to systematically examine the interactions between Hg biogeochemical cycling and cryospheric changes. This paper presents a comprehensive Hg dataset encompassing air (2 stations), aerosols (9 stations), precipitation (16 stations), glaciers (12 glaciers; including snowpit, surface snow, and cryoconite samples), soils (50 sites), surface waters (53 locations; including river, lake, and glacial meltwater), glacier ice cores (1 core), and lake sediment cores (8 cores) collected across the Third Pole. The data were acquired through both in situ (online) monitoring and laboratory analyses. High-resolution atmospheric Hg concentrations were measured using a Tekran 2537B analyzer at the Nam Co and Tanggula stations. Spatial and temporal distributions of Hg in aerosols, precipitation, glaciers, soils, and sediment cores revealed distinct patterns and trends across different sectors of the Third Pole, influenced significantly by emission sources, transport pathways, and environmental processes. Depositional chronologies derived from glacier ice and lake sediment cores reflect anthropogenic perturbations in the historical Hg record since the Industrial Revolution. Stable Hg isotope compositions from aerosols, soils, and lake sediments provide evidence for transboundary transport of Hg pollution and its northward incursion into the interior Tibetan Plateau from South Asia. This updated dataset is made publicly available to support interdisciplinary research linking the cryosphere, atmosphere, soils, and hydrology. The data are archived in standardized Excel format and accessible through the institutional repository of the State Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou (Kang et al., 2024).
The authors have conducted long-term, high-altitude field observations across the Third Pole under extremely challenging conditions. The resulting comprehensive mercury dataset-covering air, aerosols, precipitation, glaciers, soils, waters, ice cores, and sediment cores-represents a remarkable logistical and scientific achievement. Given the outstanding observational efforts and the overall good quality of the data presented, the manuscript is promising. The clarity of the writing and the value of the dataset are commendable. I recommend acceptance after a moderate revision, as this dataset will serve as a valuable resource for the cryospheric and environmental geochemistry community.
Major concerns
As a data paper, the manuscript lacks critical QA/QC metadata, including detection limits, analytical precision, blank corrections, and reference material results for each measurement matrix (air, aerosols, precipitation, snow, soils, waters, ice cores, sediment cores, and Hg isotopes). A comprehensive QA/QC table should be provided to ensure data transparency and reusability.
The dataset spans a vast and heterogeneous region yet relies on only two air monitoring stations, one ice core, and limited spatial coverage for several media. The authors should add a concise statement in the data description acknowledging these spatial limitations, discuss how the existing data still support the main conclusions, and clarify which findings are regionally robust versus site‑specific. This is essential for proper use of the dataset by the community.
Specific concerns