Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas, Norway.
Sci Total Environ. 2013 Sep 1;461-462:734-41. doi: 10.1016/j.scitotenv.2013.05.054. Epub 2013 Jun 14.
In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic ice core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An ice core chronology of (236)U, (239)Pu, and (240)Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6m deep ice core from the Austfonna glacier at Nordaustlandet, Svalbard is presented. The ice core chronology corresponds to the period 1949 to 1999. The main sources of Pu and (236)U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of (239+240)Pu ranged from 0.008 to 0.254 mBq cm(-2) and (236)U from 0.0039 to 0.053 μBq cm(-2). Concentrations varied in concordance with (137)Cs concentrations in the same ice core. In contrast to previous published results, the concentrations of Pu and (236)U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The (240)Pu/(239)Pu ratio ranged from 0.15 to 0.19, and (236)U/(239)Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to (236)U concentrations and (236)U/(239)Pu atom ratios in the Arctic and in ice cores.
在本工作中，应用最先进的同位素指纹技术对北极冰芯进行分析，以定量测量 U 和 Pu 的沉积，并确定来自前苏联试验场塞米巴拉金斯克（中亚）和新地岛（北冰洋）的可能的对流层传输的碎屑。本文介绍了在斯瓦尔巴群岛诺德奥斯特兰德的奥斯特冰川采集的 28.6 米深冰芯中，通过加速器质谱法测量的（236）U、（239）Pu 和（240）Pu 浓度和原子比的冰芯年代学。冰芯年代学对应于 1949 年至 1999 年期间。北极地区 Pu 和（236）U 的主要污染源是 1945 年至 1980 年期间的大气核爆炸，以及前苏联试验场新地岛和塞米巴拉金斯克的对流层沉降物。（239+240）Pu 的活度浓度范围为 0.008 至 0.254 mBq cm(-2)，（236）U 的活度浓度范围为 0.0039 至 0.053 μBq cm(-2)。浓度与同一冰芯中的（137）Cs 浓度一致。与以前发表的结果相反，在对应于暂停前时期（1949 年至 1959 年）的深度处，Pu 和（236）U 的浓度比暂停后时期（1961 年和 1962 年）高。（240）Pu/（239）Pu 比值范围为 0.15 至 0.19，（236）U/（239）Pu 比值范围为 0.18 至 1.4。Pu 原子比值在核大气试验最集中的时期（1952 年至 1962 年）内处于全球沉降的范围内。据作者所知，这是首次在北极地区和冰芯中报道（236）U 浓度和（236）U/（239）Pu 原子比值的生物地球化学循环方面的研究。
