Distribution of radionuclides in the river sediments and coastal soils of Chittagong, Bangladesh and evaluation of the radiation hazard

The concentrations and distribution of natural and anthropogenic radioactive materials in sediments and soils from around the two major rivers and coastal area of Chittagong, Bangladesh were investigated with an aim of evaluating the environmental radioactivity and radiation hazard. In the sediment and soils in general, the concentration of 232Th was found to be higher than that of the 238U and the activities of 232Th and 238U in this area are higher than the world average. 137Cs was observed in all the samples, ranging from 0.4 to 3.88 Bq kg−1. The radium equivalent activities, emanation coefficients and radon exhalation rates were estimated for the sediment and soils; the emanation coefficients, radon exhalation rates and dose rates were found to be higher than the world average values.