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| Titel |
90Sr and 89Sr in seawater off Japan as a consequence of the Fukushima Dai-ichi nuclear accident |
| VerfasserIn |
N. Casacuberta, P. Masqué, J. Garcia-Orellana, R. Garcia-Tenorio, K. O. Buesseler |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 6 ; Nr. 10, no. 6 (2013-06-03), S.3649-3659 |
| Datensatznummer |
250018275
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| Publikation (Nr.) |
 copernicus.org/bg-10-3649-2013.pdf |
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| Zusammenfassung |
| The impact of the earthquake and tsunami on the east coast of Japan on 11
March 2011 caused a loss of power at the Fukushima Dai-ichi nuclear power
plant (NPP) that resulted in one of the most important releases of artificial
radioactivity into the environment. Although several works were devoted to
evaluating the atmospheric dispersion of radionuclides, the impact of the
discharges to the ocean has been less investigated. Here we evaluate the
distribution of Fukushima-derived 90Sr (n = 57) and 89Sr (n = 19)
throughout waters 30–600 km offshore in June 2011. Concentrations of
90Sr and 89Sr in both surface waters and shallow profiles ranged
from 0.8 ± 0.2 to 85 ± 3 Bq m−3 and from 19 ± 6 to
265 ± 74 Bq m−3, respectively. Because of its short half-life,
all measured 89Sr was due to the accident, while the 90Sr
concentrations can be compared to the background levels in the Pacific Ocean
of about 1.2 Bq m−3. Fukushima-derived radiostrontium was mainly
detected north of Kuroshio Current, as this was acting as a southern boundary
for transport. The highest activities were associated with near-shore eddies,
and larger inventories were found in the closest stations to Fukushima NPP.
The data evidence a major influence of direct liquid discharges of
radiostrontium compared to the atmospheric deposition. Existing 137Cs
data reported from the same samples allowed us to establish a
90Sr / 137Cs ratio of 0.0256 ± 0.0006 in seawater off
Fukushima, being significantly different than that of the global atmospheric
fallout (i.e., 0.63) and may be used in future studies to track waters coming
from the east coast of Japan. Liquid discharges of 90Sr to the ocean
were estimated, resulting in an inventory of 53 ± 1 TBq of 90Sr
in the inshore study area in June 2011 and total releases of 90Sr
ranging from 90 to 900 TBq, depending upon the reported estimates of
137Cs releases that are considered. |
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