Transfer factors of 226Ra, 232Th and 40K from fertilised soil to different types of field crops in Tikrit city, Iraq

Abstract

Natural radionuclide activity concentrations in fertilised soil and field crops, as well as the transfer factor from fertilised soil to field crops, were measured. The measurements were carried out using gamma ray spectroscopy with a Nal(TI) detector. The geometric mean (geometric standard deviation) for soil-to-crop transfer factors for each study site were 0.57(1.37), 0.41(1.53) and 0.41(1.51) for 226Ra, 232Th and 40K, respectively. The geometric mean transfer factor of 232Th in the present study is 19 times higher than the world mean value, whereas the geometric mean transfer factors of 226Ra and 40K are less. The results show that the fertilised soil samples and field crops pose no radioactive risk and that there are no immediate health risks associated with the use of these samples in the areas under investigation. Furthermore, there was no correlation between 232Th and 226Ra concentrations, possibly because these radionuclides are transported differently in soil.