Identification of oxidation state of plutonium in the snow layers, High Tatras, Czechoslovakia

Snow layers in lasting snow fields in High Tatras are effectively isolated from each other by ice crust. Every layer has a specific amount of fallout particles, pH, concentration of dissolved ions. Plutonium oxidation state (VI), from the adsorption behaviour of the isotopes of U, Th, Ra, Sr and Mn in six independent layers was elucidated. Behaviour of plutonium was similar to that of226Ra and90Sr. Isotopes of Th showed quite different dependence in snow layers. Concentration of Th and Mn in snow has similar extreme, which imply higher oxidation state of Mn than Mn(II). Behaviour of uranium may be explained by a mixture of U(VI) and U(IV) oxidation states because of their dependence in successive snow layers is a superposition of the same dependences of226Ra (or90Sr) and thorium isotopes.