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Iron concentrations in the Southern Ocean are thought to act as a driver of the regular glacial–interglacial cycles in atmospheric carbon dioxide (CO 2). This study presents the concentrations of bioavailable Fe (dissolved Fe (DFe) and total dissolved Fe (TDFe)), major ions (Na+, K+, Mg2+, Ca2+, Cl−,NO 3 ‐,SO 4 2‐ and methanesulfonic acid (MSA)), heavy metal elements (Sr, Pb, V, Ti and Cd), and rare earth elements (REEs; specifically, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and the oxygen and hydrogen isotopic compositions (δ18O and δD) from a series of surface snow samples collected during from January 22 to February 5, 2017 along a traverse from Zhongshan Station to Dome A in East Antarctica. The results reflect the Antarctic surface snow Fe and the other trace element concentrations on the East Antarctica ice sheet. In particular, the DFe and TDFe concentrations were measured using inductively coupled plasma sector field mass spectrometry (SF-ICP-MS). The concentration patterns of DFe and TDFe show three different stages along this transect. First, there is an abrupt decrease with distance inland from the coast and then a slight decreasing trend with increasing elevation. The maximum concentrations were observed at distances of 450–600 km from the coast, indicating that there are different potential sources and/or transporting air masses. The variations show that the sources and processes that deliver bioavailable Fe differ along this transect. These data are useful for assessing bioavailable Fe release from the Antarctic ice sheet. Unlabelled Image • The distribution of trace elements (including Fe) in East Antarctica is presented. • There are multiple sources of Fe along the transect of Zhongshan to Dome A. • The Fe peaks 450–600 km from the coast are associated with low-latitude transport. [ABSTRACT FROM AUTHOR]

Abstract Perchlorate concentration in a shallow ice core at Tienshan, East Asia ranged between 0.55 and 52.1 ng L−1, with significant temporal variations during 1956–2004. Since the 1980s, a clear increasing trend of perchlorate was observed in the Miaoergou ice core, possibly the result of elevated stratospheric chlorine levels caused by emissions of anthropogenic volatile chlorine compounds. Although differences in trends and amounts were observed, the 1956–2004 perchlorate data from this study compares well with the perchlorate data from the High Arctic ice cores. The spatial and temporal differences of the perchlorate in Miaoergou ice core may be due to differences in anthropogenic sources. Such as, the nitrate ore field in Turpan-Hami Basin in eastern Xinjiang, China, may be the primary anthropogenic source. From the organic chlorine species emission data, HCFC-141b, HCFC-142b and HCFC-124 were identified as the primary anthropogenic sources responsible for the two perchlorate spikes observed for 1980–1996 and 1997–2001. The Miaoergou ice core covering the 1956–2004 period provides further evidence for the perchlorate deposition variations between mid-latitudes and the High Arctic regions. Graphical abstract Unlabelled Image Highlights • The perchlorate concentrations (fluxes) were reconstructed during 1956–2004, Tienshan ice core, East Asia. • The trend of perchlorate concentrations significantly increased since 1980 with increasing anthropogenic activities. • There are multi-anthropogenic emissions result in perchlorate increasing during 1956–2004. [ABSTRACT FROM AUTHOR]