12.3.1 Resuspension and Deposition Dynamics of
137
Cs
on Romanian Territory
The Chernobyl NPP accident spread a huge amount of fission products over Europe
(Egorov et al. 2010).
The simulation of the movement of the radioactive cloud starting on April
26 until May 10 is presented on http://www.irsn.fr/FR/popup/Pages/tchernobyl_
video_nuage.aspx. NERSN detected the increase of artificial radioactivity in aerosol and deposition samples as of the late hours of April 30, 1986 (Sonoc et al.
1989b).
131 I was first measured in aerosol samples collected May 1st, 1986 (103 Bq/
m
3 ) at Paring station and at Toaca Station (63 Bq/m
3 ).
The highest aerosol and deposition concentrations were registered at the mountain NERSN stations Toaca and Babele. Also locations like Tg.Mures, ClujNapoca, Drobeta Tr.Severin situated on the axis NE-SW and Tulcea, registered
high values (Osvath and Dovlete 1992). The lesser levels were registered in the NW
part of Romania (Oradea and Satu-Mare).
The lowest and highest annual deposition rates for Romanian stations are
presented in Fig. 12.1.
Measurements of soil samples confirmed an inhomogeneous deposition pattern
of the Chernobyl fallout. Once deposited on the ground the radionuclides undergo a
series of biogeochemical processes and may constitute a source for atmospheric
radioactivity through resuspension over long periods of time (Raes et al. 1991). The
resuspension of radionuclides from contaminated soil into the atmosphere is one of
the key processes that should be considered in the estimation of inhalation doses to
humans, therefore following the Chernobyl accident many studies focused on the
presence and the decline of
137 Cs in the atmosphere as a consequence of
resuspension process. Research done to better understand the resuspension process
and predict the time dependence of the resuspension was published by (Nicholson
1988; Vintersved et al. 1991; Garger et al. 1998; Dovlete and Osvath 1993; Garger
et al. 1997; Hatano and Hatano 1997, 2003) and reviewed by (Maxwell and
Anspaugh 2011; Garger et al. 2012).
Garger et al. (1998) proposed a temporal dependence of the resuspension factor,
K(t), in agreement with experimental data from the Chernobyl region,
K t
ð Þ ¼ K 0
ð Þ exp À0:002 t
ð
Þ
where t is the time expressed in days.
The majority of the expressions proposed for resuspension as a function of time
contained the exponential decrease or/and power law decrease for medium and long
term. Different models are analysed in the literature (Maxwell and Anspaugh
2011). The data and model in (Dovlete and Osvath 1993) show that for the first
decade after deposition the exponential dependence of the resuspension factor is a
good approximation.
208
C. Dovlete et al.
137
Cs
on Romanian Territory
The Chernobyl NPP accident spread a huge amount of fission products over Europe
(Egorov et al. 2010).
The simulation of the movement of the radioactive cloud starting on April
26 until May 10 is presented on http://www.irsn.fr/FR/popup/Pages/tchernobyl_
video_nuage.aspx. NERSN detected the increase of artificial radioactivity in aerosol and deposition samples as of the late hours of April 30, 1986 (Sonoc et al.
1989b).
131 I was first measured in aerosol samples collected May 1st, 1986 (103 Bq/
m
3 ) at Paring station and at Toaca Station (63 Bq/m
3 ).
The highest aerosol and deposition concentrations were registered at the mountain NERSN stations Toaca and Babele. Also locations like Tg.Mures, ClujNapoca, Drobeta Tr.Severin situated on the axis NE-SW and Tulcea, registered
high values (Osvath and Dovlete 1992). The lesser levels were registered in the NW
part of Romania (Oradea and Satu-Mare).
The lowest and highest annual deposition rates for Romanian stations are
presented in Fig. 12.1.
Measurements of soil samples confirmed an inhomogeneous deposition pattern
of the Chernobyl fallout. Once deposited on the ground the radionuclides undergo a
series of biogeochemical processes and may constitute a source for atmospheric
radioactivity through resuspension over long periods of time (Raes et al. 1991). The
resuspension of radionuclides from contaminated soil into the atmosphere is one of
the key processes that should be considered in the estimation of inhalation doses to
humans, therefore following the Chernobyl accident many studies focused on the
presence and the decline of
137 Cs in the atmosphere as a consequence of
resuspension process. Research done to better understand the resuspension process
and predict the time dependence of the resuspension was published by (Nicholson
1988; Vintersved et al. 1991; Garger et al. 1998; Dovlete and Osvath 1993; Garger
et al. 1997; Hatano and Hatano 1997, 2003) and reviewed by (Maxwell and
Anspaugh 2011; Garger et al. 2012).
Garger et al. (1998) proposed a temporal dependence of the resuspension factor,
K(t), in agreement with experimental data from the Chernobyl region,
K t
ð Þ ¼ K 0
ð Þ exp À0:002 t
ð
Þ
where t is the time expressed in days.
The majority of the expressions proposed for resuspension as a function of time
contained the exponential decrease or/and power law decrease for medium and long
term. Different models are analysed in the literature (Maxwell and Anspaugh
2011). The data and model in (Dovlete and Osvath 1993) show that for the first
decade after deposition the exponential dependence of the resuspension factor is a
good approximation.
208
C. Dovlete et al.