Environmental Engineering Reference
In-Depth Information
TABLE 18.4
Distribution (%) by Layers of Material SFM-I of I, Te, and Ru in Samples
SFM-I Material Layers
Sampling Date
(1986)
Component
Aerosol
Upper Facing
First Sorption Layer
Second Sorption Layer
May 8
—
?
?
?
131
I
69.4
19.4
11.2
—
103
Ru
88.7
4.2
7.1
—
106
Ru
84.0
5.2
10.8
—
132
Te
91.7
3.3
5.5
—
May 14
—
0.25
a
5.1
a
2.5
a
131
I
72.5
19.8
7.7
—
103
Ru
97.4
1.0
1.6
—
106
Ru
96.0
2.0
2.0
—
132
Te
99.0
—
1.0
—
May 15
—
0.29
a
4.7
a
2.7
a
131
I
42.4
19.2
18.7
19.7
103
Ru
99.4
—
0.6
—
106
Ru
97.3
—
2.7
—
May 16
—
0.26
a
2.4
a
2.7
a
131
I
41.4
34.5
20.4
3.7
103
Ru
96.1
1.9
2.0
—
106
Ru
97.1
—
2.9
—
May 17
—
0.28
a
5.0
a
4.2
a
131
I
28.0
41.0
28.0
3.0
103
Ru
97.7
—
2.3
—
106
Ru
100
—
—
—
May 19
—
0.24
a
5.0
a
3.5
a
131
I
8.9
64.5
22.2
4.4
103
Ru
87.0
7.0
6.0
—
106
Ru
87.8
5.7
6.5
—
a
Quantity of sorbent in layer (mg/cm
2
).
of gaseous components of the Chernobyl accident provided in Europe, United States, and Japan.
Summary data of the global atmosphere monitoring phase composition of
131
I at different periods
after the Chernobyl accident [27] are presented in Figure 18.6.
From the majority of measurements performed in the irst 29 days after the accident, it is clear
that gaseous I concentration was higher than aerosol concentration, and 1 month after the accident
(data from Japan and United States) it was still higher than 0.7.
After deposition on the particle I compounds can leave its surface due to desorption. If desorp-
tion probability is close to the duration of sampling, the second desorption can take place between
different parts of the sampler. Therefore, experimental data on aerosol-gas ratio can be higher than
the actual value [28].
Taking into account the correction on desorption, it was found that the real portion of gas-
eous iodine was in the range of 0.33-0.63 with a mode of 0.48 [28]. In [29,30] it was found that
133
I was in gaseous form in the same proportion with aerosols as
131
I, and in the period from
April 29-May 2 the gaseous fraction was 60%-80%. From this, the important conclusion can
be drawn that the behavior of
129
I and
135
I in the atmosphere was similar. It was also found that
132
Te was in the air in gaseous form with 10% of its general concentration, which was the same
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