RADIONUCLIDE DISTRIBUTION IN COM-PONENTS OF THE SARBALYK LIMNETICSYSTEM (BARABA LOWLAND, WESTERN SIBERIA)

Abstract

Geochemical and mineralogicalanalysis of the bottom sediment cores of smalllakes can be used as the basis forradio-ecological monitoring and environmentalprotection measures. Here, features of theradionuclide activity distribution in componentsof the limnetic ecosystems of the central Barabalowland were studied, and factors affectingradiocesium absence in the bottom sediment ofLake Sarbalyk were identified. Fieldworkincluded the sampling of limnetic ecosystemcomponents, bottom sediment weighing, andthe determination of pH, Eh, TDS and oxygencontent. Subsequent laboratory investigationinvolved the determination of major and traceelement concentrations by atomic absorptionspectrometry and X-ray fluorescence analysis;mineral composition by X-ray diffractometry(XRD); analysis of sample morphology and composition via scanning electron microscopy;and natural radionuclide and radiocesium con-tent determination by the gamma-spectrometricmethod. Radiocesium is present in all the stud-ied lake bottom sediments of the central Barabalowland in the upper horizons, with the excep-tion of Lake Sarbalyk. Limnetic ecosystem com-ponents were analyzed using modern analyticalmethods, considering the distribution features ofnatural and artificial radionuclides in catchmentarea soils, tussocks and the bottom sediment ofLake Sarbalyk. The results revealed that the ab-sence of radiocesium in the bottom sediment ofLake Sarbalyk is due to two factors: the charac-teristics of the lake overgrowth and the sorptionof dissolved forms of137Cs.