Radionuclides from the Fukushima accident in the air over Lithuania: measurement and modelling approaches

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• 作者：G. Lujanien? ; S. By?enkien? ; P.P. Povinec ; M. Gera
• 关键词：Fukushima accident ; Aerosols ; Iodine-131 ; Caesium-134 ; 137 ; Plutonium-238 ; 239+240
• 刊名：Journal of Environmental Radioactivity
• 出版年：2012
• 出版时间：December, 2012
• 年：2012
• 卷：114
• 期：Complete
• 页码：71-80
• 全文大小：3100 K

文摘

Analyses of ¹³¹I, ¹³⁷Cs and ¹³⁴Cs in airborne aerosols were carried out in daily samples in Vilnius, Lithuania after the Fukushima accident during the period of March-April, 2011. The activity concentrations of ¹³¹I and ¹³⁷Cs ranged from 12?¦ÌBq/m³ and 1.4?¦ÌBq/m³ to 3700?¦ÌBq/m³ and 1040?¦ÌBq/m³, respectively. The activity concentration of ^239,240Pu in one aerosol sample collected from 23 March to 15 April, 2011 was found to be 44.5?nBq/m³. The two maxima found in radionuclide concentrations were related to complicated long-range air mass transport from Japan across the Pacific, the North America and the Atlantic Ocean to Central Europe as indicated by modelling. HYSPLIT backward trajectories and meteorological data were applied for interpretation of activity variations of measured radionuclides observed at the site of investigation. ⁷Be and ²¹²Pb activity concentrations and their ratios were used as tracers of vertical transport of air masses. Fukushima data were compared with the data obtained during the Chernobyl accident and in the post Chernobyl period. The activity concentrations of ¹³¹I and ¹³⁷Cs were found to be by 4 orders of magnitude lower as compared to the Chernobyl accident. The activity ratio of ¹³⁴Cs/¹³⁷Cs was around 1 with small variations only. The activity ratio of ²³⁸Pu/^239,240Pu in the aerosol sample was 1.2, indicating a presence of the spent fuel of different origin than that of the Chernobyl accident.