leaching of Some Fission Products from Soil BERND KAHN O a k Ridge N a t i o n a l Laboratory, O a k Ridge, Tenn.
A simple procedure permits the radiochemical determination of radionuclides of cesium, strontium, yttrium, cerium, ruthenium, zirconium, and niobium adsorbed on soil. The procedure consists of leaching the radionuclides with appropriate volumes and concentrations of boiling nitric, oxalic, or sulfuric acid; separation of the radionuclides from nonradioactive ions leached from the soil; and standard radiochemical separations. To determine the leaching efficiency of various solutions, radioactive tracers were adsorbed on Conasauga shale from aqueous solutions and then leached from the shale. It was found that 99% of the adsorbed radionuclides could be removed from the soil by the leach solutions. By modifying existing radiochemical procedures, it was possible to remove the contaminating nonradioactive ions leached from the soil and thus obtain the radionuclides free of ions which could interfere with their radiochemical determination.
cesium-137, ruthenium-106, cerium-144, zirconium-95, niobium95, and strontium-yttrium-90. (Cesium, ruthenium, cerium, and strontium-yttrium were obtained as the chlorides; zirconium and niobium as oxalate complexes.) The first three were counted as liquids in a well-type sodium iodide scintillation counter a t radioactive equilibrium, so that a count rate proportional to the activity of the parent radionuclides was obtained. Xiobiurn-95, which has no radioactive daughter, was also counted with the scintillation counter. Zirconium-95 samples were evaporated on watch glasses 1 inch in diameter, under heat lamps, and counted with aluminum absorbers on end-w
