Levels of Lanthanides and Natural Radionuclides in the Uncultivated Soils Near Industrial Area of Bangladesh

Twenty-five uncultivated surface soil samples collected from the northern and southern regions of Dhaka Export Processing Zone (DEPZ), industrial area of Bangladesh, were analyzed for their contents of Y, lanthanides and natural radionuclides (Th and U) using an inductively coupled plasma mass spectrometer (ICP-MS). Analogous concentrations of the Y, lanthanides, Th and U were observed in the both regions of DEPZ around several kilometer distances. Further, the measured values showed no particular contamination. However, the concentrations of the light lanthanides (La, Ce and Nd) in the Bangladeshi soils were around twice the worldwide average value. But, the smooth curve of the chondrite normalized patterns of the lanthanides suggested that the lanthanide contents of the Bangladeshi soils in this area are the results of the natural dispersion process rather than anthropogenic activities. In addition, the relatively high Th and U concentrations and Th/U ratio were observed in Bangladeshi soils of this area, most likely due to the effect of their parent materials such as clay stones which have a high Th/U ratio. Since this is the first precise result for the Y, lanthanides, Th and U contents in Bangladeshi soils, it could be useful in understanding the background level and the characteristics of these elements in Bangladeshi soils.