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Asian dust has significant impacts on atmospheric systems and global biogeochemical cycles. In this study, we applied the U isotopic method to trace sediments based on their comminuting age, analyzing the uranium isotopes of cryoconite samples from various glaciers in western China, including the Tibetan Plateau (TP) and Tianshan Mountains. We aimed to explore the spatial variability of the (234U/238U) activity ratio and residence time, as well as the transport mechanism of the dust cycle in the region. Additionally, we used Nd‐Sr isotopes data from our previous work to jointly determine the provenance. Our results indicate that the average (234U/238U) activity ratios in southern TP glaciers are higher, with mean range of 0.981–0.993, while those in northeastern TP locations are lower, with mean of 0.974. This suggests a decreasing trend from south to north. In the Tianshan region, the (234U/238U) activity ratio is higher in central areas compared to eastern areas, with a mean range of 0.984–0.996, indicating a decreasing trend from west to east. U‐Sr‐Nd isotopes analysis showed that dust provenance is from multiple sources, including long‐range transported and local dust inputs from the glacier basins, mainly originating from the TP surface and central Asian arid regions. Using the end‐member mixing model analysis and meteorological data, we interpret that the cryoconite dust in eastern Tianshan and Qilian Mountains comes from a complex mixture of the southern Gobi, northern TP surface dust, and Taklimakan and Alxa arid deserts. In contrast, the glacial dust in southern TP locations originates mainly from the plateau surface dust. Our findings suggest that the uranium isotopes in high‐altitude glaciers are primarily influenced by the origins of dust, which are affected by related atmospheric circulation. We also developed a conceptual model to illustrate the complete process of U isotopic fragmentation and migration changes during dust production, transport, and deposition in the TP region. Plain Language Summary: In this study, the U isotopic method to trace sediments depending on their production‐transport histories is applied for the first time to dust deposited on glaciers in various locations of Tibetan Plateau (TP) and Tianshan Mountains in western China. The U isotopic variability of dust from glacial sediment is presented and discussed here, providing valuable data for a broader application of uranium isotopes for sedimentology and provenance studies in the future. Results showed that the (234U/238U) activity ratio signature of dust from glaciers is not uniform but exhibits differences depending on the considered geographic sector of the TP and western China. The present study demonstrates the potential of the 234U/238U technique to gather information about the production history of mineral dust deposited on glaciers in complex contexts as the TP and improve the identification of dust sources. Key Points: We measured the (234U/238U) activity ratio of cryoconite dust in large range scale of western China (including the Tibetan Plateau and Tianshan Mountains)The (234U/238U) activity ratio in high‐altitude glaciers is mainly affected by different source regions and transport processA conceptual model shows the complete view of U isotopic fragmentation and migration change during the dust transport and deposition [ABSTRACT FROM AUTHOR]

Iron (Fe) as a limiting nutrient has profound impacts on ecosystems and the global biogeochemical cycle. Field observations were made at the atmosphere—snowpack interface in various glaciers of the Tibetan Plateau. The formand chemical properties of the Fe detected were investigated in laboratory using TEM‐EDX measurements, to obtain insights in the content and sources of Fe in aerosol pollutants in glaciers, as well as micro‐structure changes and their environmental effects, as well as interface transformation dynamics. We find that Fe occurs in forms of aggregated and single particulates with diameter d < 5 μm. The Fe particulates collected from different locations show clear spatial heterogeneity, with fly ash and soot constituting the major components of anthropogenic Fe. The concentration of Fe aggregates with pollutants (e.g., sulfate and nitrate) is dominant in regions close to the areas of human activity. Moreover, in the remote areas of the interior plateau, an increased concentration of mineral Fe particles is found in the aggregates. These observations are crucial to elucidate the evolution processes of pollutant‐Fe mixing, from generation or emission through anthropogenic activities to accumulation in remote areas and modification of Fe occurrence form during transportation. Our results also show that, during interface deposition, soluble Fe particle concentration increased by 13.8% on average, as Fe solutes with sulfate‐coating enhances of the dissolution of Fe in fly ash‐soot and minerals—a process that produces large quantities of ultrafine Fe particle under reductive dissolution in snowpack. Overall, these changes significantly contribute to enhancing the bioavailable iron content in the study areas affecting thereby the glacier ecosystem. Plain Language Summary: This study aims at providing an important record of the individual Fe particulates and pollutant mixing states, and to document the variability in the occurrence form and chemical properties over the regions comprising the glacier/snowpack and atmosphere interface. The objective is to determine the Fe‐salt (Sulfate/Nitrate pollutants) mixing state changes from the atmosphere to the glacier/snowpack surface, to elucidate the content and source of Fe‐rich particles in aerosols at the atmosphere‐snowpack interface over the cryosphere of the Tibetan Plateau, and to shed light on the factors influencing the physical and chemical properties of these particles. Key Points: Fe particulate reveal clear spatial heterogeneity with fly ash and soot constituting the major components of anthropogenic FeFe solutes from the sulfate‐coating led to an enhancement of dissolved Fe from fly ash‐soot and mineralsThe interface changes contribute to enhance the bioavailable iron content in the study area significantly [ABSTRACT FROM AUTHOR]

Heavy metals present a substantial threat to both the environment and human health. Considering the delicate ecological equilibrium of the Tibetan Plateau (TP) and its heightened susceptibility to anthropogenic impacts, scholarly attention has progressively turned toward the examination of heavy metal pollution within the plateau's environment. In this study, we conducted a comprehensive analysis of various heavy metals (As, Cr, Co, Ni, Cu, Mo, Cd, Pb, and Sb), utilizing topsoil samples collected from the TP during the period of 2018–2021. Additionally, snow and cryoconite samples obtained from TP glaciers during the same timeframe were also subjected to analysis. The results indicate elevated concentrations of total heavy metals in the eastern and western TP (328.7 μg/g), as opposed to the central and southern TP (145.7 μg/g). Most heavy metals exhibit a consistent spatial distribution pattern. High Enrichment Factors (EFs) and Geoaccumulation Index (I geo) values for As and Cd suggest their enrichment in TP topsoil. Receptor modeling identified three primary sources of heavy metals within the topsoil: industrial sources (42.3%), inherent natural sources within the surface soil (20.6%), and vehicular emissions (14.2%). Substantial differences in heavy metal concentrations and spatial distribution were observed between the topsoil and the glacial snow-cryoconite matrix. The prominent presence of Sb in the snow-cryoconite matrix, in contrast to its low abundance in the topsoil, indicates distinct source influences of long-range transported materials between the two environments. Our inference suggests that the influence of heavy metals from distant pollutants undergo mixing and dilution in the topsoil due to the presence of local indigenous heavy metals, although such influence is notably observed on the glacier surface of the TP. Consequently, this underscores the significant impact of long-range transported sources on heavy metals, surpassing the influence of local TP soils, to the alpine glaciers and even other atmospheric sediments in Tibetan Plateau. [Display omitted] • We investigated heavy metals composition of TP topsoil and snow-cryoconite. • Most heavy metals exhibit a consistent spatial distribution pattern in TP soil. • High EFs and I geo values for As and Cd suggest their enrichments in TP topsoil. • Substantial spatial differences were observed between topsoil and glacial samples. [ABSTRACT FROM AUTHOR]

Toxic and major elements, such as As and Fe, in watersheds can significantly impact the surrounding water environment and ecosystem. Thus, in this study, we conducted an investigation into the origins and spatial distribution of typical toxic trace elements (As and Mn) and crustal major elements (Al, Fe, and Ti) in suspended particulate matter (SPM) across various glacial watersheds located at different elevations in the northeastern Tibetan Plateau (NETP) from June to July in 2017. The results revealed that the mean value of each element followed the order of abundance in the samples, with Al having the highest mean value at 21307 µg/L, followed by Fe at 13366 µg/L, Ti at 1520 µg/L, Mn at 245 µg/L, and As at 66.6 µg/L. Moreover, our study identified high content of these elements from the Dabanshan Snowpack, Laohugou Glacier No.12, and Yuzhufeng Glacier in the upper reaches of the basin, which were found to be 9.9, 10.2, and 19.4 times higher, respectively, than that of the upper reaches of the Heihe River. We found that As and Mn exhibited clear indications of anthropogenic influence on a local and regional scale. The calculated enrichment factor (EF) demonstrated a significant As enrichment (EF>100) in the Qiyi and Lenglongling Glaciers, possibly resulting in the release of upstream glacier melt and anthropogenic-derived As deposition. Our findings suggested that the upstream region was primarily linked to glacier meltwater discharge. In contrast, the middle and lower reaches of the basin exhibited a more pronounced influence from local human activities. Based on the findings, the water environment of the glacier watershed appears to be in good condition overall. However, the presence of elevated levels of As element in the water system can be traced back to both anthropogenic and natural factors. As a result, ensuring the safety of the water supply for nearby residents is a matter of utmost concern. This study provides a comprehensive examination of hydrochemical variations and the overall water environment of high-altitude glacier basins in the NETP, offering valuable insights into the topic. [Display omitted] • Elemental concentration indicated a increasing trend in HG, LG, and QG basins, while in DS, LG12, and YG inverse. • As was significantly enriched, probably affected by regional coal combustion and other anthropogenic sources. • Relationship between elemental composition and various sources in upstream and downstream were very different. [ABSTRACT FROM AUTHOR]

Although the Tibetan Plateau is widely thought as a potential dust source to the atmosphere over East Asia, little is known about the temporal changes of Tibetan dust activities and Tibetan dust source strength. In this study, we address these two issues by analyzing dust storm frequencies and aerosol index through remote sensing data and by means of numerical simulation. The findings indicate that monthly dust profiles over the Tibetan Plateau vary significantly with time. Near the surface, dust concentration increases from October, reaches its maximum in February-March, and then decreases. In the middle to upper troposphere, dust concentration increases from January, reaches its maximum in May-June, and decreases thereafter. Although Tibetan dust sources are important contributors to dust in the atmosphere over the Tibetan Plateau, their contribution to dust in the troposphere over eastern China is weaker. The contribution of Tibetan dust sources to dust in the atmosphere over the Tibetan Plateau decreases sharply with height, from 69% at the surface, 40% in the lower troposphere, and 5% in the middle troposphere. Furthermore, the contribution shows seasonal changes, with dust sources at the surface at approximately 80% between November and May and 45% between June and September; in the middle and upper troposphere, dust sources are between 21% from February to March and less than 5% in the other months. Overall, dust aerosols originating from the Tibetan Plateau contribute to less than 10% of dust in East Asia. [ABSTRACT FROM AUTHOR]

Abstract: The northeast Asian dust process during the spring seasons in the years 1982–2006 was simulated by the Integrated Wind Erosion Modeling System (IWEMS). The influence of Arctic Oscillation (AO) on dust activities was investigated by analyzing surface observations and model simulations. There is a significant relationship between AO and dust activity; a positive AO phase is associated with decreased (increased) dust storm frequency in Mongolia (Taklimakan Desert) and enhanced anticyclonic (southeastward) dust transport over northwestern China (North China). The AO-dust relation is mainly due to changes in the westerly jet and geopotential height in the middle troposphere; a positive AO phase induces a northward shift of the polar jet, an intensified westerly jet over northern Tibetan Plateau, and a positive geopotential height anomaly over Mongolia. The northern shift of the polar jet reduces the frequency of intense cyclones in Mongolia, thereby causing a decrease in the dust storm frequency. The intensified westerly jet stream over the northern Tibetan Plateau increases the dust storm frequency in the Taklimakan Desert. The positive geopotential height anomaly over Mongolia initiates an anticyclonic dust transport anomaly in the middle troposphere over northwestern China. It also induces a southeastward dust transport anomaly over North China. The reverse situations are true for a negative AO phase. [ABSTRACT FROM AUTHOR]

The analysis of uranium isotope ratio 235U/238U in environmental media serves as a reliable method to distinguish between natural and anthropogenic sources of uranium, playing a crucial role in assessing the extent of contamination with anthropogenic uranium and disturbances in its biogeochemical cycle. In this study, we focus on the northeastern Tibetan Plateau to examine the atomic ratio of 235U and 238U in riverine suspended particulate matter (SPM) across eight glacial watersheds. Results reveal that the 235U/238U atomic ratio in the suspended load ranges from 0.007247 to 0.007437 (with an average value of 0.00727 ± 0.00003), which closely aligns with the ratio found in natural uranium (0.00725). The highest mean ratio (0.00729 ± 0.00007) is observed in the upper glacial basin of the Ningchan River. Results suggest the negligible influence of isotopically altered in relation to human nuclear activities. When considering different environmental media, such as soil, snow/cryoconite, and riverine suspended particulate matter in the study area, the 235U/238U ratio in surface soil presents the highest values, pointing to a slight enrichment of 235U. This may be attributed to the fact that soil retains the cumulative signals of uranium atmospheric deposition, including the deposition of 235U-enriched airborne particulate matter deposited after atmospheric nuclear tests carried out in the second half of the 20th century. On the contrary, riverine suspended particulate matter and glacial sediments are more influenced by the natural 235U/238U signature under modern environmental conditions. This confirms that the northeastern Tibetan Plateau is still relatively pristine with respect to biogeochemical disturbances related to human activities. [Display omitted] • the 235U/238U of glaciated river systems in the northeastern Tibetan Plateau closely aligns with natural levels. • the NE Tibetan Plateau experienced a mild deposition of enriched 235U during the global nuclear weapon testing. • the NE Tibetan Plateau is currently not significantly contaminated by human nuclear-related activities. [ABSTRACT FROM AUTHOR]