121
• Biological absorption coefficient BAC (Alexakhin and Korneyev 1992)
BAC
Radionuclide concentration in the plant ash
Gross radionuclid
=
e e concentration in the soil
When oats were cultivated on different soils of the non-chernozem zone of the
Russian Federation, where
238
U was introduced as a solution of uranyl chloride with
concentrations of 25 and 50 mg kg
−1
of soil, the negative effect of the radionuclide
on the growth, development and formation of plant productivity was not established.
The primary amount of
238
U in sod-podzolic, grey forest soils and chernozems is in
the exchangeable state (40–70%), which determines the high values of AC of
238
U
for oats grain and straw (Table 3). The acid-soluble fraction of soil is important on
typical sierozem, and the content of the exchange fraction on sod-podzolic, grey
forest soils and chernozems plays a leading role in the intake of
238
U from the soil
into the plants.
Mordberg et al. (1976) studied the effect of various concentrations of
238
U on the
growth and yield of plants on the example of corn on leached chernozem in the
North Caucasus. It was found that concentrations of
238
U exceeding 2.5 kBq kg
−1
(200 mg kg
−1
of soil) caused growth inhibition and a decrease in yield due to the
toxic effect of the radionuclide on the development of the root system. Depending
on the physical and chemical properties of the soils, the degree of the growth inhibition of corn plants was different, and the weight of plants when introducing
238
U into
the soil ranged from 14% to 21% in comparison with the control (Mordberg et al.
1976). The accumulation of
238
U by barley, oats and vetch plants on sod-podzolic
soil containing 10, 100, 500 and 1000 mg kg
−1
was to a certain level in a direct but
not proportional dependence on the concentration of
238
U in the soil. In the range of
very high concentrations in the soil (over 500 mg kg
−1
), the accumulation of
238
U by
Table 3 Accumulation coefficients of
238
U in the yield of oats on different soils’ greenhouse
experiment, AC of
238 U (Bq kg
−1 plant dry weight) (Bq kg
−1 soil)
−1
Soil
238 U − 312.5 Bq kg
−1 of soil
238
U – 625 Bq kg
−1 of soil
Weight, g
pot
−1
AC
238 U,
n × 10
−3
Weight, g
pot
−1
AC
238
U,
n × 10
−3
Grain Straw Grain
Straw Grain Straw Grain
Straw
Sod-podzolic sandy loam
20.6
27.4 2.92
20.0 21.2
26.5 2.85
20.2
Sod-podzolic sandy loam
13.2
26.1 4.08
23.9 14.9
25.4 3.97
24.5
Sod-podzolic medium loamy 17.2
22.7 3.48
25.4 18.3
24.2 3.23
23.3
Sod-podzolic medium loamy 16.7
23.9 3.15
24.6 17.1
25.8 3.32
22.0
Sod-podzolic medium loamy 15.9
27.0 3.00
20.2 16.2
28.2 2.90
18.2
Grey forest
medium loamy
19.4
28.4 2.20
15.8 20.3
29.7 2.32
16.4
Chernozem
leached
medium loamy
21.8
30.5 1.49
9.4 22.0
31.0 1.53
9.6
The Behaviour of Uranium in Soils and the Mechanisms of Its Accumulation…
• Biological absorption coefficient BAC (Alexakhin and Korneyev 1992)
BAC
Radionuclide concentration in the plant ash
Gross radionuclid
=
e e concentration in the soil
When oats were cultivated on different soils of the non-chernozem zone of the
Russian Federation, where
238
U was introduced as a solution of uranyl chloride with
concentrations of 25 and 50 mg kg
−1
of soil, the negative effect of the radionuclide
on the growth, development and formation of plant productivity was not established.
The primary amount of
238
U in sod-podzolic, grey forest soils and chernozems is in
the exchangeable state (40–70%), which determines the high values of AC of
238
U
for oats grain and straw (Table 3). The acid-soluble fraction of soil is important on
typical sierozem, and the content of the exchange fraction on sod-podzolic, grey
forest soils and chernozems plays a leading role in the intake of
238
U from the soil
into the plants.
Mordberg et al. (1976) studied the effect of various concentrations of
238
U on the
growth and yield of plants on the example of corn on leached chernozem in the
North Caucasus. It was found that concentrations of
238
U exceeding 2.5 kBq kg
−1
(200 mg kg
−1
of soil) caused growth inhibition and a decrease in yield due to the
toxic effect of the radionuclide on the development of the root system. Depending
on the physical and chemical properties of the soils, the degree of the growth inhibition of corn plants was different, and the weight of plants when introducing
238
U into
the soil ranged from 14% to 21% in comparison with the control (Mordberg et al.
1976). The accumulation of
238
U by barley, oats and vetch plants on sod-podzolic
soil containing 10, 100, 500 and 1000 mg kg
−1
was to a certain level in a direct but
not proportional dependence on the concentration of
238
U in the soil. In the range of
very high concentrations in the soil (over 500 mg kg
−1
), the accumulation of
238
U by
Table 3 Accumulation coefficients of
238
U in the yield of oats on different soils’ greenhouse
experiment, AC of
238 U (Bq kg
−1 plant dry weight) (Bq kg
−1 soil)
−1
Soil
238 U − 312.5 Bq kg
−1 of soil
238
U – 625 Bq kg
−1 of soil
Weight, g
pot
−1
AC
238 U,
n × 10
−3
Weight, g
pot
−1
AC
238
U,
n × 10
−3
Grain Straw Grain
Straw Grain Straw Grain
Straw
Sod-podzolic sandy loam
20.6
27.4 2.92
20.0 21.2
26.5 2.85
20.2
Sod-podzolic sandy loam
13.2
26.1 4.08
23.9 14.9
25.4 3.97
24.5
Sod-podzolic medium loamy 17.2
22.7 3.48
25.4 18.3
24.2 3.23
23.3
Sod-podzolic medium loamy 16.7
23.9 3.15
24.6 17.1
25.8 3.32
22.0
Sod-podzolic medium loamy 15.9
27.0 3.00
20.2 16.2
28.2 2.90
18.2
Grey forest
medium loamy
19.4
28.4 2.20
15.8 20.3
29.7 2.32
16.4
Chernozem
leached
medium loamy
21.8
30.5 1.49
9.4 22.0
31.0 1.53
9.6
The Behaviour of Uranium in Soils and the Mechanisms of Its Accumulation…