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New insights into particle-bound trace elements in surface snow, Eastern Tien Shan, China
2020
Huang, Ju | Wu, Guangjian | Zhang, Xuelei | Zhang, Chenglong
Trace elements (TEs) in the insoluble particles of surface snow are less affected by melting processes and can be used as environmental proxies to reveal natural and anthropogenic emissions. Here the first comprehensive study of the 16 TEs (Al, As, Ba, Bi, Cr, Cu, Fe, Mn, Ni, Pb, Sn, Sr, Ti, U, V, and Zn) in insoluble particles (>0.45 μm) from surface snow samples collected at Urumqi Glacier No. 1 (UG1), Eastern Tien Shan, China, from February 2008 to January 2010 were presented. Results show that concentrations of most insoluble particulate TEs (TEs ᵢₙₛₒₗ) in the snow were higher in summer while lower in winter, due to the increasing particle inputs and melting processes. The abundances of As, Cr, Cu, Ni, Pb, and Zn in some samples were higher than those in surrounding urban soils, which might due to these TEs have further anthropogenic input beyond the already contaminated re-suspended urban soil particles and TEs were mainly enriched in particles with small grain size. Based on enrichment factor (EF) and principal component analysis (PCA), our results suggest that eight TEs (Al, Fe, Ti, Ba, Mn, Sr, U, and V) mainly came from mineral dust, while the remaining eight TEs (As, Bi, Cr, Cu, Ni, Pb, Sn, and Zn) were affected by coal combustion, mining and smelting of non-ferrous metals, traffic emissions, and the steel industry. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggests that pollutants might originate from Xinjiang province, Kazakhstan, and Kyrgyzstan. Moreover, UG1 received more significant inputs of particle-bound pollutants in summer than in winter due to the stronger convection and the prevailing valley wind that transports pollutants from the city of Urumqi.
Show more [+] Less [-]Natural versus anthropogenic sources and seasonal variability of insoluble precipitation residues at Laohugou Glacier in northeastern Tibetan Plateau
2020
Wei, Ting | Kang, Shichang | Dong, Zhiwen | Qin, Xiang | Shao, Yaping | Rostami, Masoud
This study employs the grain size distributions and the concentrations and isotopic compositions of Sr, Nd, and Pb in the precipitation samples collected from the Laohugou Glacier (LHG) in northeastern Tibetan Plateau (TP) during August 2014–2015 to investigate seasonal variability in the insoluble precipitation particle sources. Fine dust particle (0.57–27 μm) depositions dominated in autumn and winter, whereas both fine and coarse dust particle (27–100 μm) depositions were found in spring and summer. Furthermore, the concentrations of Sr, Nd, and Pb also varied seasonally—the highest and lowest Sr and Nd concentrations were recorded in spring and autumn, respectively, whereas the highest and lowest Pb concentrations were recorded in winter and summer, respectively. The Sr and Nd isotopes revealed that the dust in the winter precipitation originated predominately from the Taklimakan Desert and that in spring originated from the Badain Jaran and Qaidam deserts. The precipitation residues in summer were derived from a complex mixture of dust sources from the Gobi and other large deserts in northwest China. Autumn residues were predominately sourced from local soil near the LHG as well as from the Qaidam Basin and the northern TP surface soil. The Taklimakan, long suspected as a major source of long-range transported dust, was an insignificant contributor to the precipitation over LHG during spring, summer, and autumn. Further, the Pb isotopic ratios indicated a primary impact of anthropogenic pollutants for most part of the year (except spring). Meteorological data and the MODIS AOD model are in good agreement with the results from the analyses of the Sr, Nd, and Pb isotopes for the LHG particle source, and further clarify the source regions. Thus, this study thus provides new evidence on the seasonal variability of the sources of the residual particles in remote glaciers in Central Asia.
Show more [+] Less [-]Atmospheric pollution revealed by trace elements in recent snow from the central to the northern Tibetan Plateau
2020
Li, Yuefang | Huang, Ju | Li, Zhen | Zheng, Kui
In order to determine the current levels, spatial distribution patterns, and potential pollution of trace elements (TEs) in the atmosphere of the Tibetan Plateau (TP), snow pit samples were collected in May 2016 from five TP glaciers: Qiyi (QY), Hariqin (HRQ), Meikuang (MK), Yuzhufeng (YZF), and Xiaodongkemadi (XDKMD). Concentrations of 13 TEs (Al, Ba, Cd, Co, Cr, Cu, Fe, Li, Pb, Sb, Sr, U, and Zn) in the snow were measured. The spatial distribution patterns and depth profiles of TEs from the studies sites revealed that the influence of dust on TEs was more significant on the MK and YZF glaciers than on the QY, HRQ, and XDKMD glaciers. The spatial distributions of TE EFFₑ values differed from their concentrations, however. The enrichment factor (EF) values and concentrations of some TEs in the YZF, QY, and XDKMD glaciers revealed that the pollution levels of these elements were significantly lower than those found in previous research. Examination based on EFs, principal component analysis, as well as the calculated non-dust contributions of TEs, revealed that dust was the principal source for most TEs in all five glaciers, while biomass burning was another potential natural source for TEs in some glaciers, such as QY. In contrast, Cd, Ba, Sr, Cu, Pb, Zn, and Sb were occasionally affected by anthropogenic sources such as road traffic emissions, fossil fuel combustion, and mining and smelting of nonferrous metals in and beyond the TP. Air mass backward trajectories revealed that potential pollutants were transported not only from local sources but also from Xinjiang Province in northwestern China, as well as South Asia, Central Asia, the Middle East, and Europe.
Show more [+] Less [-]Seashore sediment and water chemistry at the Admiralty Bay (King George Island, Maritime Antarctica) – Geochemical analysis and correlations between the concentrations of chemical species
2020
Potapowicz, Joanna | Szumińska, Danuta | Szopińska, Małgorzata | Bialik, Robert Józef | Machowiak, Katarzyna | Chmiel, Stanisław | Polkowska, Żaneta
This study covers water and sediment chemical characteristics by the western shore of Admiralty Bay (King George Island, Antarctica) in 2016. Chemical processes between sediment and water have been described based on the determination of ions, metals, non-metals, and TOC concentrations. Rock weathering is an important source of Fe, Ni, Co, Al in the seashore area. The PCA shows the impact of acidification in the release metals from sediment. Our results indicate that riverine mineral fluxes need to be accounted for as the volume of melt increases in response to climate change. Based on geoaccumulation indexes (anthropogenic fingerprint), we observed an increased concentration of Pb (Igₑₒ = 1.643), in the lake near station facilities and Cd in the area of Ecology Glacier (Igₑₒ > 1.389). Taking into account climate change and the intensification of anthropopressure, our study indicates that Antarctica requires a special focus on the seasonal dynamics of mineral content and pollution assessment.
Show more [+] Less [-]Processes driving heavy metal distribution in the seawater of an Arctic fjord (Hornsund, southern Spitsbergen)
2020
Zaborska, Agata | Strzelewicz, Agnieszka | Rudnicka, Paulina | Moskalik, Mateusz
The temporal and spatial variability of heavy metal distribution was studied in an Arctic fjord (Hornsund, Spitsbergen). Seawater from 8 sampling stations and 3 sampling depths was collected in 6 successive months and used for measurement of dissolved and particulate heavy metal concentrations. Salinity and temperature profiles were determined prior to sampling and water masses were classified according to their properties. Isotopic lead composition (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁶Pb/²⁰⁸Pb ratios) was studied to find the sources of Pb to the fjord seawater. Hornsund seawater was contaminated with the studied heavy metals (particularly during the summer months). Extremely high contamination with Cd was measured (dissolved up to 488 ng·L⁻¹, while particulate up to 303 ng·L⁻¹), which is most probably connected to high atmospheric deposition. Depending on the season and the region, metal distribution was modified by glacier meltwater and surface run-off discharges, melting of fast ice, direct atmospheric deposition, transport of sea salt, intrusion of Atlantic water, sediment re-suspension, as well as re-mobilization.
Show more [+] Less [-]Black carbon in surface soil of the Himalayas and Tibetan Plateau and its contribution to total black carbon deposition at glacial region
2020
Gautam, Sangita | Yan, Fangping | Kang, Shichang | Han, Xiaowen | Neupane, Bigyan | Chen, Pengfei | Hu, Zhaofu | Sillanpää, Mika | Li, Yizhong
At present, the glaciers in the Himalayas and the Tibetan Plateau (HTP) are retreating partly due to albedo reduction caused by deposited light-absorbing impurities such as mineral dust (MD) and black carbon (BC). Because BC also exists widely in MD from surface soil, it is necessary to further evaluate the contribution of BC from MD to the total BC at glacier region. This will help to improve the study of BC sources by considering the relative contributions from MD and direct combustion sources. Therefore, in this study, concentrations of total organic carbon (TOC) and fine particles of BC from 43 surface soil samples of the HTP were investigated. The contribution of BC from MD to total BC deposited at the glacier region was evaluated. The results showed strong correlations between TOC and BC of studied samples (R² = 0.70, p < 0.01), suggesting that they have similar sources and activity characteristics. The average BC concentration of studied samples was 2.02 ± 1.55 mg g⁻¹, much lower than those of particles deposited at the glacier region and other regions with high soil TOC concentration. The contributions of BC from MD to total surface BC at two glaciers of the inner HTP (Zhadang and Xiaodongkemadi) were 17.66 ± 10.84% and 20.70 ± 16.35%, respectively. Therefore, the contribution of MD to glacier melting of the HTP is higher than that of previously assumed after BC coming along with MD is considered. Because MD concentration is higher at north and west part of the HTP, the contributions of MD at these glacier regions should be larger than previously assumed.
Show more [+] Less [-]Source, mobility, and bioavailability of metals in fjord sediments of Krossfjord-Kongsfjord system, Arctic, Svalbard
2020
Choudhary, Shabnam | Nayak, Ganapati N. | Khare, Neloy
Krossfjord-Kongsfjord system situated on the west coast of Svalbard archipelago is an ideal location to investigate the impacts of climate change on the environment. As a consequence of global warming, metal concentrations in the Arctic region are increasing due to permafrost melting and changes in biological processes. Therefore, the fjord sediments were studied for identification of provenance, mobility, bioavailability, and potential toxicity of metals in the fjord environment. Finer sediments and organic matter were found to be higher away from the glacier outlets, while coarser sediments were found to be higher near the glacier head. Illite, kaolinite, and chlorite constituted the clay mineral assemblage which had slightly influenced the metal distributions. The variations in metal abundance were attributed largely to the glacial activity along with the influence of Atlantic water mass in western Spitsbergen. Fjord system received sediment from the weathering of rocks indicating an input of terrigenous material. Comparison of metals in bulk sediment with Arctic sediment quality guidelines (ASQGs) showed that Zn and Cu were enriched in the sediment. However, to avoid the overestimation of the risk associated, fractionation of the metals was carried out which revealed higher Mn and Co in labile phases that pose a considerable risk to the biota.
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