Reload Index (ZRiChK UMCS)

 

 

STUDIES ON HORIZONTAL AND VERTICAL MIGRATION

OF 90Sr ISOTOPES IN SOILS FROM BUG RIVER VALLEY

 

STANISŁAW CHIBOWSKI, JAN SOLECKI,

 

DEPARTMENT OF RADIOCHEMISTRY AND COLLOID CHEMISTRY

 

 

Almost 99% of isotopes from global fallout get to soil in the end. Accumulated in upper layers of the soil these isotopes may transfer into root system of plants then enter a food chain. In presented papers studies on horizontal (towards the river and its bottom sediments) and vertical migration of 90Sr are presented.

Along the Bug river 10 sampling points were selected. For the examination of horizontal migration the soil samples were taken at 2-5m and 20-50m from the river. In each point bottom sediment was also collected. 20x30x5 cm profiles were taken in the same points for studies of the vertical migration.

The distribution of 90Sr in soil and sediment samples is presented in tables 1 and 2.

Table 1. Radioactivity of 90Sr in soil and bottom sediment samples in Bq/kg.

 

Activity in Bq/kg

Sample number

C (soil)

B (soil)

A (sediment)

B1

15.51

15.87

8.57

B2

6.65

15.11

13.58

B3

21.63

16.03

12.57

B4

19.29

21.28

12.19

B5

54.3

36.39

20.48

B6

45.22

17.22

9.07

B7

69.78

85.33

4.85

B8

16.06

14.18

10.37

B9

31.53

6.77

3.65

B10

5.31

9.65

4.19

 

Obtained results allow to formulate the following conclusions:

 

n   horizontal transfer of 90Sr isotope, towards the river and bottom sediments is unconfirmed

Table 2. Radioactivity of 90Sr in the layers of the soil profile.

No.

Radioactivity 90Sr [Bq/kg]

Weight of layer [g]

Radioactivity 90Sr [Bq/m2/cm]

No.

Radioactivity 90Sr [Bq/kg]

Weight of layer [g]

Radioactivity 90Sr [Bq/m2/cm]

B1A1

4

2246

30

B3B1

7

4822

113

B1A2

7

2691

63

B3B2

6

3298

66

B1A3

6

2805

56

B3B3

7

4084

95

B1A4

5

2740

46

B3B4

6

2980

60

B1A5

5

3859

64

B3B5

2

4155

28

B1A6

4

3165

42

B3B6

4

4006

53

B1B1

6

2574

51

B4A1

5

2852

48

B1B2

5

3189

53

B4A2

8

3580

95

B1B3

4

3744

50

B4A3

7

3208

75

B1B4

5

3400

57

B4A4

2

3953

26

B1B5

3

3799

38

B4A5

2

4071

27

B2A1

4

4427

59

B4A6

2

3930

26

B2A2

11

3544

130

B4B1

< MDA

3859

< MDA

B2A3

5

3676

61

B4B2

< MDA

4295

< MDA

B2A4

3

3357

34

B4B3

3

5312

53

B2A5

3

4971

50

B4B4

3

4306

43

B2A6

2

3852

26

B4B5

< MDA

3891

< MDA

B2B1

7

2391

56

B4B6

< MDA

3992

< MDA

B2B2

7

3196

75

B10A2

3

5085

51

B2B3

4

2471

33

B10A3

1

5420

18

B2B4

7

3300

77

B10A4

< MDA

5380

< MDA

B2B5

5

3548

59

B10A5

1

5569

19

B2B6

9

2687

81

B10A6

< MDA

5780

< MDA

B3A1

3

4444

44

B10B1

1

5205

17

B3A2

5

3754

63

B10B2

2

5663

38

B3A3

5

4632

77

B10B3

4

5227

70

B3A4

4

3955

53

B10B4

3

5236

52

B3A5

2

4687

31

B10B5

< MDA

5681

< MDA

B3A6

1

5507

18

B10B6

3

5440

54

-        MDA – Minimum detectable amount with coincidence system

 

n   mean activity of 90Sr in surface layers of the soil is 26 Bq/kg and in bottom sediments is 10 Bq/kg

n   radioactive strontium fallout on studied territory, calculated from obtained results, was 0.35 kBq/m2/cm

n   measured radioactivity in analyzed profiles ranged from 17 to 130 kBq/m2/cm

n   90Sr was detected down to 30 cm of the soil profile

n   vertical migration of cesium is complex process that is reflected by lack of regular distribution of its activity in the profile layers.

 

Grant KBN 3T09C 03415