Radioactivity concentrations in soil and vegetables from the northern Jordan Rift Valley and the corresponding dose estimates

The Jordan Rift Valley (JRV) is considered the food bowl of Jordan, especially during the winter season. In this study, soil and vegetable samples collected from greenhouses in the northern JRV were analysed for their radioactive content. The activity concentrations of 238U, 235U, 232Th, 226Ra, 137Cs and 40K in soil were found to be (± SD) 33 ± 12, 2.2 ± 0.7, 11.2 ± 3.3, 40.5 ± 15.5, 3.5 ± 1.3 and 156.0 ± 46.6 (Bq kg-1), respectively. In vegetables, the activity concentration of 40K was found in the range of 698-1439 Bq kg-1, while those of 226Ra and 228Ra were found to be in the range of <0.61-2.56 and <0.69-3.35 Bq kg-1, respectively. Transfer factors for 40K were found to be high and ranged from 5 to 8, while those for 226Ra and 228Ra were found to be from <0.01 to 0.07 and from <0.09 to 0.42, respectively. The calculated external annual effective dose is found to be within the worldwide range. (authors)