Accumulation of radionuclids in amphibians (<Emphasis Type="Italic">Pelophylax ridibundus</Emphasis> Pall.) in the Middle Urals

The accumulation levels of anthropogenic ⁹⁰Sr and ¹³⁴Cs and ¹³⁷Cs radionuclides in the marsh frog have been studied in the areas of the Beloyarskii water-storage reservoir (an industrial storm-water discharge channel of the nuclear power station) and the Verkhnii Tagil water-storage reservoir (the Tagil River down-stream of the dam). No significant distinction in the radionuclide accumulation (⁹⁰Sr and ¹³⁷Cs) depending on the amphibian sex and age is detected. Comparable levels of the accumulation of radionuclides in the marsh frog, when compared to the other representatives of the water ecosystem, are estimated. An assumption of the presence of some unidentified source of radioactive contamination of marsh frogs has been made; cesium-137 may be transferred from it to the Tagil River by the frogs.