Известия Томского политехнического университета: Инжиниринг георесурсов (Jan 2018)
Spatial distribution of radionuclide speciation in Karabulak stream of the Semipalatinsk test site
Abstract
The relevance of the issue is defined by insufficient study of migration and speciation of transuranic radionuclides in water bodies, both on a theoretic level and full-scale experiments. Problem statement of this research is determined by the aptitude of technogenic radionuclides contained in significant quantities in surface water bodies of Semipalatinsk Test Site to move beyond the nuclear test sites. The aim of the work is to study spatial distribution of artificial radionuclides and defined elements speciations in the water of the Karabulak stream. Methods. Distribution of speciations of radionuclides and some elements was studied using sequential cascade filtration. Water pH was determined by potentiometry using Anion-4100. The components of natural water chemical composition and total dissolved solids were determined in accordance with All Union State Standard 26449.1-85. Elemental analysis was performed by ICP-MS under Republic of Kazakhstan ISO standard 17294-2-2006 using Elan-9000 analytical instrument. Artificial radionuclides content was determined by arranging radiochemical separation with preparation of a counting sample for alpha spectrometry (239+240Pu) as well as gamma-spectrometry with highly sensitive semiconductor high purity germanium detector (241Am). Results. The authors have obtained the data of water chemical composition from the main tributaries of water stream Karabulak as well as the factors affecting the formation of its chemical composition. The paper introduces the data on content of radionuclides and certain elements, their speciations distribution in water of Karabulak stream. The prevailing speciation forms of technogenic radionuclides in water from the source to the confluence point as well as their quantitative changes were determined. It was defined that 137Cs migrates in dissolved form, Sm and U - in the form of suspended matter, but 239+240Pu is able to migrate in every studied speciations, and their ratio is unique for every sampling point. The activity of radionuclides, existing in dissolved form along the course of Karabulak stream, decreases in 10-100 times in the 15 km segment from the sources of contamination to the confluence of the main tributaries with congruent increase in proportion of suspended matters.
