Linear distribution of naturally occurring radionuclides in a mollic xerofluvent

The spatial variability of the specific activity of naturally occurring radionuclides in soil was investigated. Soil samples were taken from the 25- to 35-cm depth at 1-m intervals along a 100-m transect contained on a single soil series. The specific activities of 226Ra, 228Ra, 228Th, and 40K were measured by gamma spectroscopy. The existence of spatial interdependence between the specific activities was tested by calculating values of the autocorrelation function at increasing lags. No significant linear correlation was observed for the radionuclide specific activities. The values of the specific activity for all four radionuclides measured were not highly variable; the coefficients of variation obtained were < 8%. The variability of the 226Ra and 228Ra samples was completely accounted for by measurement error