The presence of terrestrial radionuclides in the Karnaphuli and Halda river sediments and concomitant hazards to the dwellers

The Karnaphuli and Halda rivers play a significant role in the ecological and commercial arena of Bangladesh, but no detailed study on radioactivity in these two rivers sediments is reported elsewhere. The present study measures the concentrations of terrestrial radionuclides in the sediment samples collected from these two rivers by using high-purity germanium (HPGe) gamma-ray spectrometry. The concentrations (Bqkg(-1)) of Ra-226, Th-232 and K-40 show in the range of 17.63 +/- 1.47-38.90 +/- 2.50, 27.86 +/- 1.76-48.80 +/- 2.70 and 324.28 +/- 26.83-640.70 +/- 42.70, respectively, which is similar to the literature data and world mean value except for four sampling locations (Kalamiabazar, Natun bridge, Rajakhali and Chaktai khal) that shows higher concentrations of primordial radionuclides. These four sampling points are located adjacent to the industrial wastes discharge channels into the Karnaphuli river. In fact, among the thousands of industries located on the bank of the Karnaphuli river, about 200 units were identified as the sources of environmental pollution. To assess human health hazards due to natural radiation, several indicators such as radium equivalent activity (Ra-eq ), external hazard index (H-ex ) and outdoor annual effective dose equivalent were calculated and compared with the recommended limits. The present results serve as an input to prepare the baseline radioactivity in commercially important river sediments prior to the operation of the first nuclear power plant in the country.

Automated summary

This study measured the concentrations of terrestrial radionuclides in sediments from the Karnaphuli and Halda rivers in Bangladesh using high-purity germanium gamma-ray spectrometry. The results showed that the concentrations of Ra-226, Th-232, and K-40 were similar to the world mean value except for four sampling locations near industrial waste discharge channels which had higher concentrations of primordial radionuclides. In addition, about 200 industrial units were identified as environmental pollution sources. Indicators such as radium equivalent activity, external hazard index, and annual effective dose equivalent were calculated to assess the human health hazards from natural radiation.