Search

This paper presents research data on water contamination levels of artificial radionuclides and heavy metals in Karabulak Creek at the Semipalatinsk Test Site. The uranium isotopic composition has been studied (235U and 238U). Priority contaminants and the most 'contaminated' sections of the Karabulak creek were identified, and water quality-related indicators were also estimated. The environmental situation around Karabulak Creek at the «Degelen» site-at which underground nuclear tests have been conducted-was found to be unique and attributed to the combined effect of man-made radiation and natural factors and, in particular, to geochemical features of the region., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2025 Dyussembayeva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Tests of nuclear weapons, various radiation accidents have led to a significant contamination of the natural environment with technogenic radionuclides and an increase in the radiation load on humans and biota. The soil cover is a kind of depot that accumulates technogenic radionuclides, from where they can enter the body of animals and humans in various ways. The migratory abilities of radionuclides and their inclusion in biological chains are determined by the properties of the radionuclides themselves, the properties of the soil, as well as the mechanism of formation of radioactive contamination. A large number of nuclear tests and experiments of various types and capacities carried out at the Semipalatinsk Test Site (STS) led to the formation of various radioactive contaminated sites that differ from each other in nature, levels and isotopic composition. One of the most studied, from the point of view of studying the forms of presence, the solubility of radioactive particles, is the territory of the 'Experimental Field' testing ground, where ground and air tests were carried out. The specifics of the experiments, namely the interaction of the soil with the high-temperature explosion zone, led to the formation of slag surfaces and vitrified particles containing technogenic radionuclides, including 239+240 Pu and 90 Sr isotopes. Information on the presence of such sparingly soluble forms of radionuclides on the territory of other testing grounds of STS is extremely scarce. The resistance of radioactive particles to leaching by mineral acids can lead to an underestimation of the content in the soil cover of hazardous radionuclides, including 239+240 Pu and 90 Sr. Ultimately, this will lead to an underestimation of the radiation hazard for the population engaged in economic activities on the territory of the landfill (grazing, haymaking and mining) or living outside it. Chemical preparation of analyzed samples is one of the most time-consuming and critical stages, which limits the performance of the entire analysis as a whole, since even the highest performance measuring instruments cannot be realized with a lot of time spent on this procedure. Decomposition of samples in autoclaves is one of the alternative methods of sample preparation, but practically devoid of the disadvantages inherent in decomposition in open systems. The advantage of using autoclaves over decomposition in open systems is that the decomposition occurs in a closed volume of the reaction chamber at elevated pressure, which increases the boiling point of liquids and, accordingly, accelerates the decomposition of particles. Thus, sample digestion occurs in a shorter time, with fewer reagents and minimal analyte loss. The last factor, along with the completeness of the decomposition, is the main indicator that affects the quality of the analysis. In this paper, we consider the method of autoclave decomposition in the determination of technogenic radionuclides in soils of STS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)