On the background level of 99TC, 90Sr and 137Cs in the North Atlantic

H. Dahlgaard; Q.J. Chen; J. Herrmann; H. Nies; R.D. Ibbett; P.J. Kershaw

doi:10.1016/0924-7963(95)00025-K

On the background level of ⁹⁹TC, ⁹⁰Sr and ¹³⁷Cs in the North Atlantic

H. Dahlgaard, Q.J. Chen, J. Herrmann, H. Nies, R.D. Ibbett, P.J. Kershaw

Research output: Contribution to journal › Journal article › Research › peer-review

Abstract

Mean concentrations of the anthropogenic radioactive oceanographic tracers ⁹⁹Tc, ⁹⁰Sr and ¹³⁷Cs 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" ⁹⁹Tc in oceanic Atlantic water. Comparison with older data indicates an observed half life for ⁹⁰Sr and ¹³⁷Cs 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 ⁹⁹Tc ⁹⁰Sr ratio (3 × 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 ¹³⁷Cs ⁹⁰Sr 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.

Original language	English
Journal	Journal of Marine Systems
Volume	6
Issue number	5-6
Pages (from-to)	571-578
ISSN	0924-7963
DOIs	https://doi.org/10.1016/0924-7963(95)00025-K
Publication status	Published - 1995

Access to Document

10.1016/0924-7963(95)00025-K

OpenUrl availability

Full text

Cite this

@article{378c4503cc8c46f69410380f61654b2d,

title = "On the background level of 99TC, 90Sr and 137Cs in the North Atlantic",

abstract = "Mean concentrations of the anthropogenic radioactive oceanographic tracers 99Tc, 90Sr and 137Cs 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{"} 99Tc in oceanic Atlantic water. Comparison with older data indicates an observed half life for 90Sr and 137Cs 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 99Tc 90Sr ratio (3 × 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 137Cs 90Sr 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.",

keywords = "Processer og stofkredsl{\o}b i {\o}kosystemer",

author = "H. Dahlgaard and Q.J. Chen and J. Herrmann and H. Nies and R.D. Ibbett and P.J. Kershaw",

year = "1995",

doi = "10.1016/0924-7963(95)00025-K",

language = "English",

volume = "6",

pages = "571--578",

journal = "Journal of Marine Systems",

issn = "0924-7963",

publisher = "Elsevier",

number = "5-6",

}

TY - JOUR

T1 - On the background level of 99TC, 90Sr and 137Cs in the North Atlantic

AU - Dahlgaard, H.

AU - Chen, Q.J.

AU - Herrmann, J.

AU - Nies, H.

AU - Ibbett, R.D.

AU - Kershaw, P.J.

PY - 1995

Y1 - 1995

N2 - Mean concentrations of the anthropogenic radioactive oceanographic tracers 99Tc, 90Sr and 137Cs 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" 99Tc in oceanic Atlantic water. Comparison with older data indicates an observed half life for 90Sr and 137Cs 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 99Tc 90Sr ratio (3 × 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 137Cs 90Sr 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.

AB - Mean concentrations of the anthropogenic radioactive oceanographic tracers 99Tc, 90Sr and 137Cs 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" 99Tc in oceanic Atlantic water. Comparison with older data indicates an observed half life for 90Sr and 137Cs 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 99Tc 90Sr ratio (3 × 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 137Cs 90Sr 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.

KW - Processer og stofkredsløb i økosystemer

U2 - 10.1016/0924-7963(95)00025-K

DO - 10.1016/0924-7963(95)00025-K

M3 - Journal article

SN - 0924-7963

VL - 6

SP - 571

EP - 578

JO - Journal of Marine Systems

JF - Journal of Marine Systems

IS - 5-6