A rapid procedure is described for the separation of plutonium radionuclides from large volumes of fresh and saline water
by means of a manganese dioxide coprecipitation technique. This procedure has been used in the laboratory and in the field
to process 50 to 400 liter water samples. Plutonium is carried through an oxidation and reduction step to insure complete
equilibration between added yield tracers and the plutonium present in the water sample. Average recovery under optimum conditions
has been 80% for seawater and over 90% for freshwater samples processed in the field with simple equipment. The procedure
can be used also to separate plutonium from water samples by direct adsorption on MnO2-impregnated cartridges. Under laboratory conditions the adsorption on MnO2 was independent of the oxidation states of plutonium in aqueous samples.