Reload Index (ZRiChK UMCS)

 

MIGRATION OF RADIONUCLIDES IN SOILS AND THEIR ACCUMULATION IN SEDIMENT OF SUPERFICIAL WATERS,

STUDY ON MIGRATION OF RADIONUCLIDES IN THE BUG RIVER VALLEY

 

STANISŁAW CHIBOWSKI, ANDRZEJ KOMOSA,

MAREK RESZKA, JAN SOLECKI, JACEK ZYGMUNT

DEPARTMENT OF RADIOCHEMISTRY AND COLLOID CHEMISTRY

 


As a continuation of the study within the project supported by International Atomic Energy Agency the horizontal and vertical migration of radionuclides (natural and artificial origin) in the Bug River valley was investigated. From the river valley ten sampling sites were chosen, where surface soil (near a riverbank and at 20-50 m distance) and sediment samples were collected. Independently, in every sampling site a soil profile was exposed and the samples were taken down to 30 cm (6 layers). Concentration of natural gamma emitters such as: 40K, 214Bi, 226Ra, 212Bi, 228Ac and anthropogenic 137Cs was determined in every samples by means of gamma spectrometry. The results of natural radionuclide concentration in the points along the Bug River show any regularity in its level changes along the course of the river. There is no difference in specific activity between soil and sediment samples (in the case of natural radionuclides). As the example the 40K concentration change along the Bug River is presented in Fig.1. In the case of the artificial nuclide - radiocaesium - its concentration in soil samples is about 4-times higher than in river sediment (and equals about 22 Bq/kg). Fig.2 shows the changes of radiocaesium activity level along the Bug River.

Figure 1. The 40K specific activity in sediment (point A) and two soil samples (point B - near the riverbank, and C - in a longer distance) collected along the Bug river.

In examined soil profiles of the Bug river natural isotopes reveal rather uniform distribution between the layers of soil, as is seen on Fig.3 in a case of 40K. Radiocaesium behaves just opposite - there is a very great difference in cesium concentration between upper soil layer and the other, deeper layers. It means that migration rate of cesium is very slow. Fig. 4 presents a distribution of radiocaesium between the layers of the soil profile. These informations can be used to calculation

of velocity of radiocaesium vertical migration in soil.


Figure 2. The 137Cs specific activity in sediment (point A) and two soil samples (point B - near the riverbank, and C - in a longer distance) collected along the Bug river.


Figure 3. Vertical distribution of 40K activity in soil samples of the Bug river (in ten points along the river).

Figure 4. Vertical distribution of 137Cs activity in soil samples of the Bug river (in ten points along the river).

 

Grant IAEA 10075