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.