Transfer of Natural Radionuclides from Soil to Plants in North Western Parts of Dhaka

The radioactivity of environmental samples from sites and suspected of contamination must be analyzed before free access is given to the public. Towards this end, plant and corresponding soil samples were collected from two different locations of North- western parts of Dhaka (Savar and Manikganj) and the activity concentrations of natural radionuclides 226 Ra ( 238 U-chain), 228 Ra ( 232 Th-chain) and non-chained 40 K were measured using gamma ray spectrometry. Soils of Savar contained more radioactive 40 K than Manikganj whereas soils of Manikganj contained more 226 Ra and 228 Ra than Savar. The influence of certain soil properties on the activity concentrations and transfer factors (TF) of natural radionuclides were investigated by correlating the observed data with those of soil properties. The activity concentrations of 40 K were much higher than those of 226 Ra and 228 Ra in plants for both locations due to higher uptake from soils. The transfer factors for 226 Ra, 228 Ra and 40 K were found to range from 0.082 to 0.926, 0.153 to 0.563 and 1.274 to 3.741 at Savar and 0.087 to 0.455, 0.061 to 0.806 and 0.738 to 1.949 at Manikganj, respectively. The soil to plant transfer factors for 40 K was found to be much higher in plants, which might be due to the essentiality of this element in plants. Our study showed that activity concentrations of these radionuclides in plants and their plant transfer factors seem to depend on the activity concentrations of the same radionuclides in soil.