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| Titel |
DISTRIBUTION OF NATURAL (U-238, Th-232, Ra-226) AND TECHNOGENIC (Sr-90, Cs-137) RADIONUCLIDES IN SOIL-PLANTS COMPLEX NEAR ISSYK-KUL LAKE, KYRGYZSTAN |
| VerfasserIn |
L. Jovanovic, B. Kaldybaev, B. Djenbaev, A. Tilenbaev |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250059849
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| Zusammenfassung |
| Researches on radionuclides distribution in the soil-plants complex provide essential
information in understanding human exposure to natural and technogenic sources of
radiation. It is necessary in establishing regulation relating to radiation protection. The aim of
this study was the radiochemical analysis of the content natural radionuclides 238U,
232Th,226Ra and technogenic radionuclides content (90Sr, 137Cs) in soils near Issyk-Kul lake
(Kyrgyzstan). Results of radiochemical analyses have shown, that the concentrations of
thorium-232 are fluctuating in the limits (11.7-84.1)Ã10-4% in the soils. The greatest
concentration of thorium-232 has been found in the light chestnut soils. The content of
uranium-238 in the soils near Issyk-Kul lake is fluctuating from 2.8 up to 12.7Ã10-4%.
Radium-226 has more migration ability in comparison with other heavy natural
radionuclides. According to our research the concentrations of radium-226 are
fluctuating in the limits (9.4-43.0)Ã10-11%. The greatest concentration of radium-226
(43,0±2,8)Ã10-11% has been determined in the light chestnut soil.
In connection with global migration of contaminating substances, including radioactive,
the special attention is given long-lived radionuclides strontium-90 and caesium-137 in
food-chains, and agroecosystems. Results of radiochemical analyses have shown, that
specific activity of strontium-90 is fluctuating in the range of 2.9 up to 11.1 Bq/kg, and
caesium-137 from 3.7 up to 14,3 Bq/kg in the soil of agroecosystems in the region of
Issyk-Kul. In soil samples down to 1 meter we have observed vertical migration of these
radionuclides, they were found to accumulate on the surface of soil horizon (0-5 cm) and
their specific activity sharply decreases with depth. In addition in high-mountain pastures
characterized by horizontal migration of cattle in profiles of soil, it was discovered
that specific activity of radionuclides are lower on the slope than at the foot of the
mountain. The content of natural radionuclides (238U, 232Th, 226Ra ) and technogenic
radionuclides (90Sr, 137Cs) in the soils depend on many factors: the type and mechanical
composition of soil, capacity of absorption, acidity, concentration of exchange forms of
carbonates, organic substances. The radionuclides accumulation process in the plants
depend on a specific accumulation ability of plants. During the researches it has been
found that radionuclides accumulate in vegetative organs more than in reproductive
parts of plants. According to the accumulation degrees of natural radionuclides
plants taking place in the following decreasing series: sugar beet > potatoes >
lucerne > clover > oats > perennial herbs > wheat > annual grass crops > barley >
corn.
Radiochemical analysis of the technogenic radionuclides in the plants has been
determined that specific activity of strontium-90 is increased in leguminous plants (cobs of
corn, lucerne) in comparison with other cultures. Caesium-137 is accumulated in beet roots,
cobs of corn and lucerne.
Key words: natural radionuclides, technogenic radionuclides, soil-plants complex,
Issyk-Kul lake, Kyrgyzstan |
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