Concentrations of radionuclides in coastal sediments from the Bay of Bengal

The natural radionuclides of uranium and thorium series as well as 40K have been determined by gamma-spectroscopy on core-profile sediments collected from the Karnafuli estuarine zone in the Bay of Bengal. The specific activity levels of the estuarine deposits are measured. The observed contents of the radionuclides present in the sediments are greatly influenced by the geomorphological conditions in the area and show the presence of concentrations of thorium and uranium radionuclides. Elevated concentrations of 226Ra and 40K values observed in the sediment may be due to the anthropogenic input of phosphate fertilizers (gypsum) into the estuarine zone from agricultural lands and wastes in the vicinity. The results have been compared with the global radioactivity measurements and evaluated.