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| Titel |
Iodine and selenium in natural water, their fixation on geochemical barriers in soils and rocks and explanation of I and Se behavior in water-solid phase system using thermodynamic modeling |
| VerfasserIn |
Elena Korobova, Boris Ryzhenko, Elena Cherkasova, Ivelina Sedykh, Nadezhda Korsakova, Victor Berezkin, Lyudmila Kolmykova, Valentina Danilova, Sabzbakhor Khushvakhtova |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250088249
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| Publikation (Nr.) |
 EGU/EGU2014-2336.pdf |
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| Zusammenfassung |
| Iodine and selenium are essential for normal functioning of thyroid gland. Their natural
deficiency in areas subjected to radioiodine contamination during nuclear tests and
accidents may increase the risk of thyroid cancer among the most sensitive groups of
population. Deficiency is caused by both the low abundance of microelements in the
environmental components of the local food chain and their fixation on geochemical
barriers due to such processes as chemical transformation, sorption, chemisorption,
complexing.
The studies of iodine and selenium distribution in soils, herbs and drinking water in rural
settlements of the Bryansk oblast’ confirmed low level of iodine and selenium content in local
soils, plants and water and revealed different character of their distribution in soils and
waters formed in geochemically different conditions of water migration in areas of
fluvioglacial, moraine and loess-like soil forming rocks (the polesje, moraine and
opolje landscapes correspondingly). Iodine content in top horizons of the soils
developed on loess-like sediments and rich in organic matter was considerably
higher as compared to those formed on sandy moraine or fluvioglacial sediments.
For selenium the difference was not pronounced. Iodine was noted for positive
correlation with Corg and fixation in the soil profile on carbonate barrier. A negative
correlation was found between selenium content in grasses and in topsoil of subordinated
elementary landscapes characterized by waterlogged and reduction conditions in
soils.
Thermodynamic modeling performed for 47 water samples on the basis of their chemical
composition helped to explain the established patterns of iodine and selenium behavior in
soil-water system. It demonstrated the possibility of existence of CaI+ and MgI+ complexes
in water and sedimentation of FeSe(cr) in presence of a considerable amount of Fe2+. Iodine
complexation with Ca and Mg ions may explain its further fixation on carbonate barrier in
soils, and selenium sedimentation may decrease its availability to plants in gley kinds of soils
elsewhere. It may be suggested that the organic water-soluble iodine complexes typical for
polesije landscapes and the mineral ones in opolje landscapes could have increased the
mobility of radioiodine isotopes and their transfer to food chains in the contaminated
areas.
The work was supported the Russian Foundation for Basic Research (grants 10-05-01148
and 13-05-00823). |
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