Does the Fukushima NPP disaster affect the caesium activity of North Atlantic Ocean fish?

Fillet samples of marine fish collected from the East/West Greenland currents (GC) and from the Baltic Sea (BS) have been investigated by gamma-ray spectrometry within the regular German monitoring programme. In samples of the second half of 2011, 134 Cs traces have been detected that are suggested...

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Bibliographic Details
Published in:Biogeosciences
Main Authors: G. Kanisch, M.-O. Aust
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2013
Subjects:
Online Access:https://doi.org/10.5194/bg-10-5399-2013
https://doaj.org/article/967eb1b40b96467c9427884940b92577
Description
Summary:Fillet samples of marine fish collected from the East/West Greenland currents (GC) and from the Baltic Sea (BS) have been investigated by gamma-ray spectrometry within the regular German monitoring programme. In samples of the second half of 2011, 134 Cs traces have been detected that are suggested to originate from the Fukushima fallout that was deposited in March/April 2011 over the northern North Atlantic and accumulated by fish. The radionuclide 134 Cs (half-life 2 yr) was indeed detected with quite small activities at about 0.0036 Bq kg −1 w.w. Existing box models describing the transport of Cs within seawater boxes of the northeast Atlantic allowed for estimation of 134 Cs contributions from other sources, i.e. from the Chernobyl fallout and from discharges by the two major European nuclear reprocessing plants; both were negligible around Greenland, while for the Chernobyl fallout a small 134 Cs background contribution to BS fish was estimated. Model results confirmed the level of 134 C measured in BS fish and showed its maximum to have occurred in winter 2011/2012 followed by a continuous decrease. It was also determined that 134 Cs activity, but not that of 134 Cs, showed a significant negative correlation with sampling depth (150–400 m) of GC fish; this strengthens our Fukushima fallout assumption. As a result, the Fukushima fallout in these sea areas only marginally enhanced (GC: 4%; BS: 0.1%) pre-Fukushima levels of individual dose rates received by human fish consumers; the addition was around 0.001 μSv following the consumption of 10 kg of fish per year, which is not expected to cause concern according to present guidelines for radiation protection.