47
processes of biological migration, since mainly from this kind of soil solutions plants
assimilate the elements of mineral nutrition and together with them absorb the radionuclides from the soil (Ovsiannikova et al. 2000; Rachkova et al. 2010).
The radionuclide redistribution in ecosystems and their entry into the human
body depend often on the content of radionuclides in soil pore waters; therefore, this
indicator is among the most important factors determining the dose loads of the
population. The samples of (0–10)-cm layers of soils for obtaining the pore solutions were sampled in 2007–2010. Location and soil type of sampling sites, content
of total organic matter (TOM), water capacity (WC), acidity (pH KCl ), and concentration activity of
238
U (A U ) in the soil samples are presented in Table 5.
The sampling sites were located far from anthropogenic sources of uranium and
at the distance of ~50 km and more from ChNNP. Presumably, uranium in the soils
from these sites was mainly of natural origin. The soil samples were represented by
sod-podzol sandy (SP S 3-SP S 10 plots), sandy loam (SP SL 3-SP SL 10 plots) and loamy
(SP L 1-SP L 3 plots), alluvial sod loamy (S L 1, S L 2, S L 3 plots), peaty-gley (P3 plot),
peat-bog (P4, P6 plots), and highly mineralized peaty (P5 plot) soils.
The samples of mineral soils of different granulometric compositions (sandy,
sandy loam, and loamy) differed markedly in the content of the “physical clay” fraction (less than 1 × 1
−5
m), the organic matter, the water capacity (WC), and the acidity. The total organic matter content (TOM) in samples of sandy and sandy loam
mineral soils was 1.8–3.4%, and in samples of loamy soils—4.0–8.5%. The content
of organic matter in samples of organic soils was in the range of 21.7–76.6% of the
mass of dry soil. Water capacity of mineral sandy and sandy loam soils varied within
26.2–38.1%; loamy, 47.1–91.0%; and organic, 114–550% of mass of absolutely dry
soil. High water capacity (more than 500% of the mass of the solid phase of the soil)
is characteristic for samples of peat-bog soils containing 68–77% total organic matter of the mass of absolutely dry samples (P3 and P4) plots). The lower water capacity (114–190%) is characterized by samples of peaty (P5 plot) and peaty-gley (P6
plot) soils with TOM 21.7 and 60.4% accordingly. This means that sandy and sandy
loam soil are capable of retaining 0.26–0.38 kg pore water; loamy soils, 0.47–
0.52 kg; and organic soils, 1.1–5.5 kg per 1 kg of solid soil phase.
Soil content of
238
U of 4.8–19.8 Bq kg
−1
(Table 5) corresponds to a radionuclide
concentration of (0.39–1.59) mg kg
−1
or (3.9–15.9) × 10
−5
wt. %; activity concentration of
238
U in soil pore solution was (0.002–0.056) Bq kg
−1
(Table 6).
The portions of
238
U in the soil pore solutions of the total radionuclide in the correspondent soil samples are shown in Fig. 2.
In mineral soils, the portion of
238
U in the pore solutions was within 0.036–0.19%
of the total uranium content in the soil samples, and the fraction of uranium in pore
solution increased from loamy soils (0.036–0.072%) to sandy loamy (0.063–
0.087%) and to sandy (0.10–0.19%) soils (Fig. 2a, b, c).
In organic soils (Fig. 2d), the fraction of
238
U in the pore solution varied in the
range 0.12–1.3%, but in most cases, it was within 0.1–0.2%. In the most species of
peat-bog and sod-podzolic sandy soils, the portions of uranium in the composition
of pore solutions were commensurable.
Uranium and Its Distribution in Typical Belarusian Soils
processes of biological migration, since mainly from this kind of soil solutions plants
assimilate the elements of mineral nutrition and together with them absorb the radionuclides from the soil (Ovsiannikova et al. 2000; Rachkova et al. 2010).
The radionuclide redistribution in ecosystems and their entry into the human
body depend often on the content of radionuclides in soil pore waters; therefore, this
indicator is among the most important factors determining the dose loads of the
population. The samples of (0–10)-cm layers of soils for obtaining the pore solutions were sampled in 2007–2010. Location and soil type of sampling sites, content
of total organic matter (TOM), water capacity (WC), acidity (pH KCl ), and concentration activity of
238
U (A U ) in the soil samples are presented in Table 5.
The sampling sites were located far from anthropogenic sources of uranium and
at the distance of ~50 km and more from ChNNP. Presumably, uranium in the soils
from these sites was mainly of natural origin. The soil samples were represented by
sod-podzol sandy (SP S 3-SP S 10 plots), sandy loam (SP SL 3-SP SL 10 plots) and loamy
(SP L 1-SP L 3 plots), alluvial sod loamy (S L 1, S L 2, S L 3 plots), peaty-gley (P3 plot),
peat-bog (P4, P6 plots), and highly mineralized peaty (P5 plot) soils.
The samples of mineral soils of different granulometric compositions (sandy,
sandy loam, and loamy) differed markedly in the content of the “physical clay” fraction (less than 1 × 1
−5
m), the organic matter, the water capacity (WC), and the acidity. The total organic matter content (TOM) in samples of sandy and sandy loam
mineral soils was 1.8–3.4%, and in samples of loamy soils—4.0–8.5%. The content
of organic matter in samples of organic soils was in the range of 21.7–76.6% of the
mass of dry soil. Water capacity of mineral sandy and sandy loam soils varied within
26.2–38.1%; loamy, 47.1–91.0%; and organic, 114–550% of mass of absolutely dry
soil. High water capacity (more than 500% of the mass of the solid phase of the soil)
is characteristic for samples of peat-bog soils containing 68–77% total organic matter of the mass of absolutely dry samples (P3 and P4) plots). The lower water capacity (114–190%) is characterized by samples of peaty (P5 plot) and peaty-gley (P6
plot) soils with TOM 21.7 and 60.4% accordingly. This means that sandy and sandy
loam soil are capable of retaining 0.26–0.38 kg pore water; loamy soils, 0.47–
0.52 kg; and organic soils, 1.1–5.5 kg per 1 kg of solid soil phase.
Soil content of
238
U of 4.8–19.8 Bq kg
−1
(Table 5) corresponds to a radionuclide
concentration of (0.39–1.59) mg kg
−1
or (3.9–15.9) × 10
−5
wt. %; activity concentration of
238
U in soil pore solution was (0.002–0.056) Bq kg
−1
(Table 6).
The portions of
238
U in the soil pore solutions of the total radionuclide in the correspondent soil samples are shown in Fig. 2.
In mineral soils, the portion of
238
U in the pore solutions was within 0.036–0.19%
of the total uranium content in the soil samples, and the fraction of uranium in pore
solution increased from loamy soils (0.036–0.072%) to sandy loamy (0.063–
0.087%) and to sandy (0.10–0.19%) soils (Fig. 2a, b, c).
In organic soils (Fig. 2d), the fraction of
238
U in the pore solution varied in the
range 0.12–1.3%, but in most cases, it was within 0.1–0.2%. In the most species of
peat-bog and sod-podzolic sandy soils, the portions of uranium in the composition
of pore solutions were commensurable.
Uranium and Its Distribution in Typical Belarusian Soils