Insight Into Radio‐Isotope 129I Deposition in Fresh Snow at a Remote Glacier Basin of Northeast Tibetan Plateau, China. Issue 13 (6th July 2018)

• Record Type: Journal Article
• Authors: Dong, Zhiwen; Shao, Yaping; Qin, Dahe; Zhang, Luyuan; Hou, Xiaolin; Wei, Ting; Kang, Shichang; Qin, Xiang
• Is Part Of: Geophysical research letters. Volume 45:Issue 13(2018)
• Page Start: 6726
• Page End: 6733
• Publication Date: 2018-07-06
• Subjects: 129I -- human nuclear activities -- elevational distribution -- glacier snowpack -- pollution transport in troposphere; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2018GL078480
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We present data of 129 I deposition in fresh snow in the Laohugou glacier basin, northeast Tibetan Plateau, in summer 2016 and 2017, and trace its source and elevational distribution in the troposphere. Our results show that the 129 I/ 127 I atomic ratios in the fresh snow on the glacier surface are about 2 orders of magnitude larger than those in the Antarctic fresh snow and 4 orders the prenuclear level, indicating a predominantly anthropogenic source of the 129 I in the mountain glacier environment of northeast Tibetan Plateau. The 129 I level in the Laohugou glacier basin is 1–2 orders of magnitude lower than at representative European locations, and not significantly higher than that observed at other sites in Asia. The 129 I/ 127 I atomic ratio and 129 I level show clear increases with elevation from 4, 300 to 5, 100 m above sea level. The 129 I in the Laohugou glacier basin is probably deposited from the upper troposphere where there exists a local maximum of 129 I. A conceptual model for interpretation of the observed 129 I concentration and profile in Laohugou is provided. Thus, this work is of importance in providing a more complete view on the transport, dispersion, and removal of 129 I in the atmosphere. Plain Language Summary: We measured the concentration measurements of 129 I, together with 129 I/ 127 I atomic ratios, deposited in the fresh snow at various altitudes, in the Laohugou glacier basin, western Qilian Mountains, northeast Tibetan Plateau. This unique dataset provides the first evidence how 129 I deposition varies with height in the middle troposphere, and a glimpse on the dispersion and pathway of anthropogenic radioiodine pollutants to the remote Tibetan Plateau glaciers. The dataset is thus an important addition to the global 129 I database. The observations at Laohugou show that 129 I increases, in contrast to 127 I and heavy metals Pb and Ni which decrease, with height in the middle troposphere. This suggests that the source of the deposited 129 I is located in the upper troposphere. A hypothetic interpretation of the observed 129 I profile is provided. Key Points: We presented variation of 129 I distribution and dispersion in the troposphere The source of the deposited 129 I in glacier snowpack is located in the upper troposphere A hypothetic model on the transport, dispersion, and removal of 129 I in the troposphere is provided