ON THE BACKGROUND LEVEL OF TC-99, SR-90 AND CS-137 IN THE NORTH-ATLANTIC

被引：38

作者：

DAHLGAARD, H

CHEN, Q

HERRMANN, J

NIES, H

IBBETT, RD

KERSHAW, PJ

机构：

[1] Risø National Laboratory

[2] Bundesamt für Seeschiffahrt und Hydrographie (BSH), Hamburg

[3] Directorate of Fisheries Research, MAFF, Fisheries Research Laboratory, Lowestoft

来源：

JOURNAL OF MARINE SYSTEMS | 1995年 / 6卷 / 5-6期

关键词：

D O I：

10.1016/0924-7963(95)00025-K

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

Mean concentrations of the anthropogenic radioactive oceanographic tracers Tc-99, Sr-90 and Cs-137 have been measured as 0.005, 1.6 and 2.5 Bq m(-3) in oceanic Northeast Atlantic surface water, east and northeast of the Azores, in 1992. This is, apparently, the first published value for fallout ''background'' Tc-99 in oceanic Atlantic water. Comparison with older data indicates an observed half life for Sr-90 and Cs-137 in the northeast Atlantic surface water of 20 yr corresponding to a mean residence time of 80-100 yr for the stable elements. The observed Tc-99/Sr-90 ratio (3 X 10(-3)) in the Azores samples is 10 times higher than the theoretical fission yield decay corrected to 1992. This is in agreement with published data on rain water samples and may be characteristic for 1960's global fallout. Furthermore, the measured Cs-137/Sr-90 ratio is not significantly different from that observed for global fallout. There do not appear to be any additional significant sources of artificial radionuclides in this region.

引用

页码：571 / 578

页数：8

共 22 条

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