Determination of Soil-to-Plant Transfer Factors for Ra-226 and Ra-228 in Some Egyptian Crops

W. M. Abdellah, A. El-Sharkawy

Soil to plant transfer factors (TF_s) of ²²⁶Ra and ²²⁸Ra have been determined for different crops, such as Cabbage, Cucumber, Kale, Aubergine, Pepper, Zucchini and Tomato. The crops were collected from some local farms in Al-Qalyubia governorate Egypt under outdoor ambient tropical conditions for two growing seasons 2014 & 2015. The crops samples and their corresponding soils were analysed for ²²⁶Ra and ²²⁸Ra using High Purity Germanium Detector (HPGe). Quality assurance objectives were followed through the efficiency calibration of the HPGe detector, background estimation, assessment of combined uncertainties and the analyses of IAEA certified soil and plant reference materials. The total activity concentrations of ²²⁶Ra(²³⁸U), ²³²Th and ⁴⁰K in soil were ranged from 6±1.2 to 87.5±4.5, 3.8±1.2 to 19.3±2.0 and 91.3±4.1 to 781.8±37 Bq kg^-1 respectively. The average activities of ²²⁶Ra and ²²⁸Ra in the crops under this investigation ranged from 0.1 to 2.8 and 0.2 to 13.9 Bq kg^-1 dry weight respectively. Cabbage and Cucumber showed maximum concentration ratios of 0.07 for ²²⁶Ra whereas for ²²⁸Ra Cabbage and Aubergine had relatively higher values of 0.13. The results obtained are within the range of the corresponding values reported by IAEA in 1994 & 2010. The present work may provide a database of TF_s for these agricultural environments to be used in radiological safety assessment models.