METHODS AND OBJECTS OF CHEMICAL ANALYSIS ISSN title: "Metody i obʺekty himičeskogo analiza" An international journal devoted to all aspects of Analytical chemistry ISSN 2413-6166 (Online), ISSN 1991-0290 (Print)
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DISTRIBUTION OF HEAVY METALS AND RADIONUCLIDES IN THE BOTTOM SEDIMENTS OF THE SMALL RIVERS OF NATIONAL NATURAL PARK «ZACHAROVANY KRAY» (TRANSCARPATIA, UKRAINE) DOWN STREAM

Symkanych O.I, Sukhareva O.Yu, Sukharev S.M.

Uzhhorod National University, Department of Chemistry

Set conformities of distribution, migration and accumulation of heavy metals (Hg, Cd, Pb, Zn, Cu), natural gamma-active nuclides (40K), elements of uranium ²³⁸U rows (²¹⁴Pb, ²¹⁴Bi, ²²⁶Ra), elements of thorium ²³²Th rows (²¹²Pb, ²¹²Bi, ²²⁸Ac, ²⁰⁸Tl), and technogenic ¹³⁷Cs in the bottom sediments of the small rivers of the National natural park «Zacharovannij kraj» (Transkarpathia, Ukraine) down stream. It is shown that content of these elements in the bottom sediments is relatively stable and can be examined as base-line, it is proportional to the siltation level of the small rivers and largely depends on their morphology. The total content of Zn in the bottom sediments of the investigated rivers is 1.64-3.73 ppm, Cu – 0.82-1.16 ppm, Pb – 0.109-0.139 ppm, Cd – 0.012-0.022 ppm, Hg – 0.007-0.013 ppm, and total specific activity of natural gamma-active nuclides (without taking into account 40К) in the bottom sedimentations it is in the limits of 126-184 Bq/kg. The set coefficients of migration of different heavy metals in the system «bottom sediments – water of the rivers» are 0.001-0.0018 that testifies to the not mobile forms of heavy metals in the bottom sediments. Educed areas of accumulation of heavy metals and radionuclides in the bottom sediments of the small rivers, credible reasons of this phenomenon are explained. Averaged data of content of heavy metals and specific activity of radionuclides in the bottom sediments of the small rivers are used for mapping of this protected territory and for the prediction of migration, also for identification of the investigated areas of the rivers taking into account the geochemical features of the region.

Key words: small rivers, bottom sediments, Hg, Cd, Pb, Zn, Cu, series ²³⁸U and ²³²Th, 40К, ¹³⁷Cs, atomic-absorption spectroscopy, gamma-spectrometry, mapping

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