Distribution of radionuclides in modern sediments of the rivers flowing into the Dnieper-Bug Estuary

O Bondarenko,V Osadchyi,S Sakhno,Vadym Gudzenko,P Nechypurenko,A Iatsyshyn,A Striuk,S Chukharev,S Semerikov,T Vakaliuk,Tetiana Alokhina,S Klimov,H Danylchuk

doi:10.1051/e3sconf/202128011003

Abstract

The article presents the results of large-scale studies of the content and distribution of natural and man-made radionuclides in the sediments of the rivers flowing into the Dnieper-Bug estuary. The article also presents the results of the granulometric analysis of the surveyed water bodies. The data about natural radioactive elements in the sediments rivers flowing into the Dnieper-Bug estuary obtained in this research are demonstrated moderate specific activity, which, however, clearly correlates with the granulometric composition of sediments. The 137Cs determined by us is contained in the sediments of all studied water bodies and the places of it greatest concentration coincide with the areas in which the sediment is represented mainly by the pelitic fraction. The data obtained in this research can serve as a baseline data in natural radionuclides concentration in sediments rivers flowing into the Dnieper-Bug estuary. The obtained data can also be used for further monitoring of the specific activity of man-made radionuclides, in particular 137Cs.

Highlights

Aquatic ecosystems play an important role in the migration of both natural and artificial radionuclides, as well as in their redistribution
The state of equilibrium in the natural decay chains of uranium and thorium depends on how certain deposits were formed − by mechanical precipitation of the suspension or by chemical or biochemical precipitation of the solution
If such an equilibrium exists, the specific activities of all members of the radioactive chain are equal to each other, and vice versa, when deposits are formed by chemical accumulation of aqueous solutions of radionuclides different in chemical properties − age equilibrium cannot exist in principle

Summary

Introduction

Aquatic ecosystems play an important role in the migration of both natural and artificial radionuclides, as well as in their redistribution. They play the role of transport arteries for migration radionuclides within the reservoir and adjacent ecosystems, on the other hand, they are natural barriers to the deposition of a certain amount of radionuclides [1]. The barrier role of hydroecosystems is determined by the nature of the reservoir, the quality and intensity of the processes that take place in it. Bottom sediments of reservoirs and watercourses, to a large extent, fulfill the mission of depositing substances entering the water from catchment areas during coastal erosion and runoff from adjacent areas. Natural radionuclides in bottom sediments reflect the geochemical features of the region. Man-made radionuclides, which include 137Cs and 90Sr, are of artificial origin, the pollution by them is carried out mainly by air way, to a lesser extent, waterways

Results

Discussion

Conclusion