Distribution of natural radionuclides in native soils of southern Saskatchewan, Canada

Little information is available on the regional distribution of natural radionuclides in agricultural environments. Surface soil samples were collected from uncultivated, unfertilized sites in the agricultural area of Saskatchewan, Canada, and analyzed for 40K, and daughters of 238U and 232Th. Activities of 40K, 214Bi (238U daughter), and 208Tl (232Th daughter) were normally distributed with means of 480, 19, and 8 Bq kg-1, respectively. Overall, the activities of all three radionuclides decreased as soil texture became coarser, while distinct geographic areas with elevated levels were probably due to local parent material composition. Natural radionuclide levels were significantly correlated to one another and the average ratio of 214Bi/208Tl/40K in native, unfertilized Saskatchewan surface soils was 1:0.45:26