This review is part of a series of studies on short-lived radionuclide accumulation in aquatic organisms following nuclear weapons testing, routine facility discharges, and accidental releases. It examines the pathways of uptake, accumulation, and internal redistribution of 125Sb, 131I, 141Ce, and 144Ce in fish representing different ecological groups. The analysis combines published literature data with our original findings obtained from studies conducted in the cooling pond of the Chornobyl Nuclear Power Plant and the Kaniv Reservoir during the post-accident period. It has been established that radionuclide accumulation is governed by their physicochemical properties, environmental speciation, and the trophic characteristics of fish. 125Sb demonstrates high bioavailability and accumulates in internal organs, gills, roe, and muscle depending on its chemical form in the aquatic environment. 131I is characterized by high solubility, rapid incorporation into biological processes, and transient retention in tissues. 141Ce and 144Ce exhibit low mobility, strong association with particulate matter, and preferential accumulation in the gastrointestinal tract, external, and mineralized tissues. At the same time, the presence of 144Ce in the muscle tissue of carnivores and piscivores suggests possible trophic transfer and does not exclude potential manifestations of limited biomagnification of this radionuclide under conditions of elevated environmental contamination. It has been determined that the ratio of 125Sb to 144Ce can be used to identify contamination sources: their co-occurrence is interpreted as evidence of fuel particle input, explaining their predominant localization in the gastrointestinal tract and, to a lesser extent, in external tissues. Conversely, their separate detection reflects differences in mobility and bioavailability. It has been shown that the principal pathways for the uptake of the investigated radionuclides by fish are particle ingestion and absorption from the dissolved phase; thus, trophic dilution predominates over biomagnification, although trophic transfer of 144Ce cannot be excluded.
Zarubina et al. (Sat,) studied this question.