Sequential extraction for radionuclide fractionation in soil samples: a comparative study

Two sequential extraction procedures, Tessierʹs method (Anal. Chem. 51(7) (1979) 844), and a current version known as Schultzʹs method (J. Environ. Radioact. 40(2) (1998) 155), were compared. The two procedures were applied to a natural soil sample that presents high activity concentrations in natural radionuclides of the 238U series. Reproducibility studies of each method and a comparison between the two sets of results were performed for uranium, thorium, and radium. The results were different for each radionuclide. Analysis of the extracted fractions was carried out by alpha spectrometry.