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 radioactiv e materials in sediments and soils from around the two major rivers and coa stal area of Chittagong, Bangladesh were investigated with an aim of evalua ting the environmental radioactivity and radiation hazard. In the sediment and soils in general, the concentration of Th-232 was found to be higher th an that of the U-238 and the activities of Th-232 and U-238 in this area ar e higher than the world average. Cs-137 was observed in all the samples, ra nging from 0.4 to 3.88 Bq kg(-1). The radium equivalent activities, emanati on coefficients and radon exhalation rates were estimated for the sediment and soils; the emanation coefficients, radon exhalation rates and dose rate s were found to be higher than the world average values. (C) 1999 Elsevier Science Ltd. All rights reserved.