Study: All of Western US and most of East Coast,
Midwest, Canada covered with airborne particles
at various altitudes on March 20,
Fukushima plume model shows —
Based solely on Reactor No. 1 explosion (PHOTO)
The following study appeared recently in the Journal of Environmental Radioactivity. A previous report 'New Study: Aerosolized plutonium from Fukushima detected in Europe — Spent fuel indicated' was based on the abstract available online at that time.
Lujanien_ e, G., et al., Radionuclides from the Fukushima accident in the air over Lithuania: measurement and modelling approaches, Journal of Environmental Radioactivity (2012), doi:10.1016/j.jenvrad.2011.12.004:
In addition to 131I and 137Cs, traces of other radionuclides were detected in the aerosol filters as well.
Their concentrations in the most active sample collected on 3-4 April 2011 14:00e06:50 UTC were:
132I e 0.12 +/- 0.01 mBq/m3
132Te e 0.13 +/- 0.01 mBq/m3
129Te e 0.40 +/- 0.04 mBq/m3
129mTe e0.75 +/- 0.25 mBq/m3
136Cs e 0.080 +/- 0.0080mBq/m3
Large collected air volumes allowed us to determine for the first time in Europe the activity ratio and concentration of Fukushima derived 238Pu and 239,240Pu isotopes. Approximately twice higher Pu activity concentration as expected, and 238Pu/239,240Pu ratio not typical either for global fallout or the Chernobyl accident was found in the integrated aerosol sample.
Here's a map published with the European-focused study:
Modelling of the Fukushima plume
For the assessment of contamination after the accident
and prediction of radioactive particle transport
the Lagrangian modelling was applied.
In order to describe the atmospheric processes realistically,
the vertical velocity, particle dissipation
and turbulence during the particle trajectory were considered.
A single release of 1015 Bq of 137Cs,
which occurred on March 12, 2011
from damaged Fukushima NPPwas analyzed.
The initial plume height,
as a result of initial vertical velocity and buoyancy,
was kept to be at 2000e3000 m.
The meteorological data and simulated trajectories revealed
that the arrival times of particles released on 11 March, 2011
and 12 March, 2011 were different,
and the particles were transported at different altitudes.
It was also obvious that the jet stream affected the transport
of emitted particles at upper atmospheric levels.
Examples of the trajectories simulated using
the Lagrangian dispersion model show (Fig. 1)
that the first signs of Fukushima released radionuclides
could be detected in the European countries (e.g. Island)
on 20 March, 2011.
Fig. 1. Particles spacing on 20 March,
2011 at 12:00 UTC (top) and on 27 March,
2011 at 18:00 UTC (bottom);
shades of red indicate particles in the bottom layer,
up to 3 km; black to dark blue indicate the middle layer,
up to 6 km height; and light blue indicates
the upper layer; the trajectories were simulated using
the Lagrangian dispersion model
(time of the particles release was on 12 March 2011).
(For interpretation of the references
to colour in this figure legend,
the reader is referred to the web version of this article.)
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