Speciation of 210Po and 210Pb in Radioactively Contaminated Soils

Differences in the migration ability of Po-210 and Pb-210 were established by the chemical fractionation of samples of radium-contaminated podzolic and alluvial-soddy soils, therewith the nature of differences did not depend on the type of soil. In the water-soluble fractions, as well as in the case of Po-210, in the exchangeable (1 M CH3COONH4, pH 7) and carbonate (1 M CH3COONH4, pH 5) fractions, the amount of radionuclides was insignificant (less than 1% of their total specific activity in samples). The highest proportion of Po-210 was found in the extracts Fe and Mn oxides and hydroxides (0.1 M NH2OH center dot HCl in 25% CH3COOH), organic matter (30% H2O2 + HNO3 up to pH 2), and amorphous silicates (0.2 M NaOH). The Pb-210 isotope was detected in significant amounts in all migrating speciations, except for the water-soluble one. Most of all, it was found in the organic matter extracts (up to 19.7% of the total content in soils). In the insoluble residue fractions, the proportion of Po-210 was 72.0 and 82.8%, that of Pb-210 was 50.0 and 76.4% of their specific activity in podzolic and alluvial-soddy soils, respectively.