DETERMINATION OF Pb-210 AND Po-210 RADIOISOTOPES IN SOIL USING EXTRACTION CHROMATOGRAPHIC TECHNIQUE

Polonium (Po-210) and Lead (Pb-210) are relatively long-lived members of the natural U-238 decay series. They contribute significantly to the radiation dose of the population. For this reason we have analyzed soil samples from different parts of Albania to determine the respective level of Po-210 and Pb-210. A radiochemical procedure is applied to separate lead and polonium simultaneously from different soil samples in the presence of the standard solution of Po. After adding Po-209 tracer and lead carrier samples are decomposed using mineral acids. Lead and polonium are selectively retained from 2M HCl solution by crown ether resin. Polonium is stripped with 6M HNO3 while lead with 6M HCl solution. The sources of polonium are prepared by spontaneous deposition onto silver disk. The activity concentration of Po-210 is determined by isotope dilution alpha spectrometry. Lead is precipitated as oxalate and the activity concentration of Pb-210 is calculated from the liquid scintillation spectrum. The chemical recoveries for Po and Pb are good and the values range in 60-80 %. Replicates, reagent blank and certified reference materials are used for the quality control purposes. In general Po-210 and Pb-210 activity concentrations in certified reference samples agreed well within the statistical uncertainty with the reference values and confidence intervals reported for these materials.