Modeling of atmospheric transfer of radionuclides in the form of water aerosols from the surface area of water bodies using the example of Lake Karachay, Russia

Abstract

Based on the analysis of multi-year monitoring data on atmospheric air contamination in the vicinity of Lake Karachay, Reservoir V-9, a model is suggested here for carry-over of radionuclides (trace elements) in the form of water aerosols from the reservoir surface area. The concept of fractionation (accumulation) coefficients is introduced for different radionuclides present in V-9 Reservoir water aerosols as compared to the reference radionuclide ¹³⁷Cs. The range of possible fractionation coefficient values is estimated for ¹³⁴Cs, ⁹⁰Sr, ^103,106Ru, ⁹⁵Zr+ ⁹⁵Nb, ¹²⁵Sb, ¹⁴⁴Ce and Pu radionuclides. It is shown that, for a numerical assessment of radioactive pollution of the atmosphere with water aerosols, it is convenient to express the capacity of the source of releases as a product of three factors: (1) the activity concentration in the reservoir water, (2) the effective rate of generation of water aerosol volume from the reservoir surface area (~ 20 cm³ m⁻² year⁻¹ in relation to the reference radionuclide ¹³⁷Cs), and (3) the fractionation coefficient of the radionuclide under consideration in water aerosols as compared to the reference nuclide. It is proposed here to model transfer and dispersion of water aerosols in the atmosphere using the standard Gaussian model, and it is shown that this allows estimation of atmospheric pollution in the vicinity of the reservoir with acceptable accuracy.