Evaluating the Parameters of the Source of Water Aerosol Generation from the V-2 Reservoir Water Area

The concentration ratio of chemical elements in a water aerosol may differ significantly from the concentration ratio of the same elements in bulk water from which this water aerosol was generated. Fractionation of chemical elements in water aerosols occurs in the surface microlayer of water and is observed only for water-soluble trace elements. For radionuclides (trace elements), the relative fractionation factor F(X/Cs) is defined as the degree of accumulation of the activity of radionuclide X in the water aerosol relative to that of another (reference) radionuclide (137Cs). The paper suggests a technique for field evaluation of relative fractionation factors for various trace elements in water aerosols that are generated by interaction of a stream of hot wastewater and cold lake water. During this interaction, air dissolved in the cold water passes into the gas phase in the form of bubbles. The technique was tested under natural conditions in the V-2 reservoir (Lake Kyzyl-Tash), in which the 90Sr activity concentration in water was 1.4 kBq/L and concentration of basic trace chemical elements was less than ~10 mg/L. The relative fractionation factors F(Y/Sr) for various trace elements in the water aerosol were estimated at ~15 for aluminum, ~13 for iron, >15 for lead, >46 for zinc, ~1.1 for calcium, ~0.3 for magnesium, and ~30 for nickel. The absolute fractionation factors F(Y) for these elements were 5.5 times higher than the relative fractionation factors. The 90Sr activity concentration in air in the vicinity of the V-2 reservoir for the period from March 21 till March 26, 2025 was estimated at ~0.2 mBq/m3 due to all sources of contamination, with the water aerosol generation contributing no more than 3%.