DISTRIBUTION FEATURES OF TRACE ELEMENTS IN BOTTOM SEDIMENTS OF THE KARABULAK STREAM, SEMIPALATINSK TEST SITE

This article presents the results of a study of the spatial distribution and occurrence forms of trace elements in the bottom sediments of the Karabulak Stream, located within the Degelen Mountains of the Semipalatinsk Test Site. Bottom sediment samples were collected at 19 points along the main stream channel and its four tributaries. A sequential extraction method was used to determine the occurrence forms of chemical elements. This method allows for the isolation of water-soluble, exchangeable, weakly specifically sorbed, organic matter-bound, iron and manganese oxideand hydroxide-bound, and residual forms. Quantitative determination of elements was performed using ICP-MS and ICP-AES. It was established that the distribution of trace elements in the bottom sediments is characterized by significant spatial heterogeneity due to the hydrological characteristics of the stream and the anthropogenic impact of the former test site. Exceedances of Clarke values were detected for a number of elements, primarily uranium, beryllium, molybdenum, and cadmium. The highest concentrations of Be, Sr, and Cd were observed in the upper reaches of the stream, while Mo and U contents increased in the lower reaches. Uranium in the bottom sediments of the main channel was shown to be predominantly in a watersoluble form, indicating its high migration capacity and potential environmental hazard.

1. Dyussembayeva M.T., Mukhamediyarov N.Zh., Yesilkanov G.M., Tashekova A.Zh., Aidarkhanov A.O. Ecological and geochemical features of some water bodies of the Semipalatinsk Test Site. Kurchatov: Intellectual Publishing House; 2023. 268 p.

2. Berezin S.A., et al. Peaceful nuclear explosions on the territory of Kazakhstan. Bulletin of the National Nuclear Center of the Republic of Kazakhstan. 2001; 7(3): 57–62.

3. Batyrbekov E.G., Aidarkhanov A.O., Vityuk V.A., et al. Comprehensive radioecological survey of the Semipalatinsk Test Site. Kurchatov; 2021. 340 p.

4. Aidarkhanova A.K., Lukashenko S.N., Korosteleva S.V. Study of sorption properties of soils in the Karabulak stream area. Bulletin of the National Nuclear Center of the Republic of Kazakhstan. 2015; 1(61): 75–84.

5. Toropov A.S., Rikhvanov L.P., Yesilkanov G.M. Spatial distribution of radionuclide occurrence forms in the water of the Karabulak stream of the Semipalatinsk Test Site. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering. 2017; 328(12): 6–15. Available at: http://izvestiya.tpu.ru/archive/article/view/1954

6. Ermakova R.G., Aidarkhanova A.K., Tleukanova Zh.E., Mamyrbayeva A.S. Study of vertical distribution of technogenic radionuclides in bottom sediments of watercourses of the Degelen site. Bulletin of the National Nuclear Center of the Republic of Kazakhstan. 2024; 4: 128–137. https://doi.org/10.52676/1729-7885-2024-4-128-137

7. Amirov A.A., Lukashenko S.N., Subbotin S.B., Kirillov V.D., Solodukhin V.P., Berdinova N.M., Zheltov D.A. Geochemical background of the Semipalatinsk Test Site: trace elements in soils of areas adjacent to the Degelen mountain massif. In: Current issues of radioecology of Kazakhstan. Issue 2. Pavlodar: Dom Pechati; 2010. p. 451–460.

8. Shakenov E.Z., Dyussembayeva M.T., Lukashenko S.N., Temirzhanova A.E., Yesilkanov G.M., Mukhamediyarov N.Zh. Spatial distribution of chemical elements in the watercourse of adit 504 at the Degelen site. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering. 2020; 331(9): 70–83.

9. Yesilkanov G.M., Mukhamediyarov N.Zh. Assessment of the elemental composition of water in the Karabulak stream (Degelen site of the former Semipalatinsk Test Site). In: Creativity of Youth – Step to a Successful Future: Proceedings of the VIII All-Russian Scientific Student Conference. Tomsk: Tomsk Polytechnic University Publishing House; 2015. p. 239–240.

10. Tessier A., Rapin F., Garignan R. Trace metals in oxic lake sediments: possible adsorption onto iron oxyhydroxides. Geochimica et Cosmochimica Acta. 1985; 49(1).

11. Ladonin D.V. Heavy metal compounds in soils: problems and methods of study. Eurasian Soil Science. 2002; (6): 682–692.

12. Vosel Yu.S., Strakhovenko V.D., Makarova I.V. Forms of uranium occurrence in lake bottom sediments of different types: Baikal region. In: Proceedings of the IV International Conference. Tomsk; 4–8 June 2013. p. 130–134.

13. Ladonin D.V. Forms of heavy metal compounds in technogenically contaminated soils. Doctoral Dissertation. Moscow; 2016.

14. Grigoriev N.A. Average content of chemical elements in rocks composing the upper continental crust. Geochemistry International. 2003; (7): 785–792.

15. Maximum permissible concentrations (MPC) of chemical substances in soils: hygienic standards GN 2.1.7.2041-06. Moscow: Information Publishing Center of the State Committee for Sanitary and Epidemiological Supervision of Russia; 2006.