TEPCO Rose

[RobertEarl]

41. Tell us what you think of this, Pam

www.elsevier.com/locate/jenvrad

Analyses of 131I, 137Cs and 134Cs in airborne aerosols were carried out in daily samples in Vilnius, Lithuania
after the Fukushima accident during the period of March-April, 2011. The activity concentrations
of 131I and 137Cs ranged from 12 mBq/m3 and 1.4 mBq/m3 to 3700 mBq/m3 and 1040 mBq/m3, respectively.
The activity concentration of 239,240Pu in one aerosol sample collected from 23 March to 15 April, 2011
was found to be 44.5 nBq/m3. The two maxima found in radionuclide concentrations were related to
complicated long-range air mass transport from Japan across the Pacific, the North America and the
Atlantic Ocean to Central Europe as indicated by modelling. HYSPLIT backward trajectories and meteorological
data were applied for interpretation of activity variations of measured radionuclides observed
at the site of investigation. 7Be and 212Pb activity concentrations and their ratios were used as tracers of
vertical transport of air masses. Fukushima data were compared with the data obtained during the
Chernobyl accident and in the post Chernobyl period. The activity concentrations of 131I and 137Cs were
found to be by 4 orders of magnitude lower as compared to the Chernobyl accident. The activity ratio of
134Cs/137Cs was around 1 with small variations only. The activity ratio of 238Pu/239,240Pu in the aerosol
sample was 1.2, indicating a presence of the spent fuel of different origin than that of the Chernobyl
accident.