Comparison of analytical methods used to determine 235U, 238U and 210Pb from sediment samples by alpha, beta and gamma spectrometry

An intercomparison of the methodology ( alpha, beta and gamma spectrometry) used for U-238, U-235 and Pb-210 determination was carried out based on 38 sediment samples. The activity range of the samples varied from 10-700 Bq/kg for Pb-210, 1-35 Bq/kg for U-235 and 10-800 Bq/kg for U-238. Results obtained using the three methods were not statistically different at high activity levels, but agreement between the results decreased at lower sample activity levels. For Pb-210, the smallest difference was found between alpha and gamma spectrometry. A good correlation between results from alpha and gamma spectrometry was observed over the whole activity range. In beta spectrometry, the results were slightly higher than those obtained by alpha or gamma spectrometry due to the impurity of Ra-228. In U-238 analysis, good correspondence was observed between U-238 determined by gamma and alpha spectrometry, particularly at higher U-238 activity concentrations over 100 Bq/kg. In U-235 analysis, attention needs to be paid to interference from Ra-226 and its reduction.