Soil-to-plant transfer factors of uranium and thorium in mining and non-mining districts of Ghana

The activity concentrations of natural radionuclides in water, soil, cassava, cocoyam and yam grown in two mining districts and a non-mining district in Ghana were determined using a high-resolution gamma spectroscopy system with high-purity germanium detector. The estimated absorbed dose for soil from Amansie, Konongo, and Mampong were 206 nGy/h, 224 nGy/h and 198 nGy/h, respectively, which were all above 60 nGy/h set by the United Nations Scientific Committee on the Effects of Atomic Radiation. The soil-to-plant transfer factors (TF) for 238U, 232Th, and 40K ranged from 0.11 to 1.11, 0.03 to 2.39, and 0.03 to 22.07, respectively. The results showed that the highest TF for 238U and 232Th were 1.11 and 2.39, respectively in cassava. There was no significant variation in the TF of 238U and 232Th among the soils in the different communities. The estimated transfer factors for 238U and 232Th for cassava, cocoyam and yam were higher than that reported by the International Atomic Energy Agency.