Iodine-129 in Snow and Seawater in the Antarctic: Level and Source

• Published in: Environmental Science & Technology
• Main Authors: Xing, Shan, Hou, Xiaolin, Aldahan, Ala, Possnert, Göran, Shi, Keliang, Yi, Peng, Zhou, Weijian
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: Nuclear fuel reprocessing; Nuclear weapons; Seawater; Snow; Anthropogenic sources; Northern Hemispheres; Nuclear activities; Nuclear weapons testing; Orders of magnitude; Reprocessing plant; Southern Hemisphere; Volatile pollutants; Iodine; /dk/atira/pure/sustainabledevelopmentgoals/life_below_water; name=SDG 14 - Life Below Water; Antarctic; The Antarctic; Antarc*; Antarctica
• Online Access: https://orbit.dtu.dk/en/publications/439f7dc7-025e-4115-aa14-4091c150ca40; https://doi.org/10.1021/acs.est.5b01234

Anthropogenic 129 I has been released to the environment in different ways and chemical species by human nuclear activities since the 1940s. These sources provide ideal tools to trace the dispersion of volatile pollutants in the atmosphere. Snow and seawater samples collected in Bellingshausen, Amundsen, and Ross Seas in Antarctica in 2011 were analyzed for 129 I and 127 I, including organic forms; it was observed that 129 I/ 127 I atomic ratios in the Antarctic surface seawater ((6.1-13) × 10 -12 ) are about 2 orders of magnitude lower than those in the Antarctic snow ((6.8-9.5) × 10 -10 ), but 4-6 times higher than the prenuclear level (1.5 × 10 -12 ), indicating a predominantly anthropogenic source of 129 I in the Antarctic environment. The 129 I level in snow in Antarctica is 2-4 orders of magnitude lower than that in the Northern Hemisphere, but is not significantly higher than that observed in other sites in the Southern Hemisphere. This feature indicates that 129 I in Antarctic snow mainly originates from atmospheric nuclear weapons testing from 1945 to 1980; resuspension and re-emission of the fallout 129 I in the Southern Hemisphere maintains the 129 I level in the Antarctic atmosphere. 129 I directly released to the atmosphere and re-emitted marine discharged 129 I from reprocessing plants in Europe might not significantly disperse to Antarctica.