Study of Natural Radioactivity and Radiological Hazard of Sand, Sediment, and Soil Samples from Inani Beach, Cox’s Bazar, Bangladesh

The radionuclide contents and their activity concentrations in beach sand, sediment and adjacent soil samples collected from Inani sea beach, Cox’s Bazar, Bangladesh were determined by using a high resolution germanium detector (HPGe) of 20% relative efficiency. A total of eighteen samples of three categories were collected and analysed. The activity concentrations of Ra, Th and K in the sand samples of the beach were found to be varied from 15.14 ± 2.62 to 28.67 ± 3.09 Bqkg, 24.39 ± 2.50 to 49.46 ± 3.58 Bqkg and 362.00 ± 79.61 to 560.87 ± 81.40 Bqkg respectively. For sediment samples the activity concentrations of the corresponding radionuclides ranged between 18.09 ± 2.66 to 53.32 ± 4.01 Bqkg, 31.01 ± 2.73 to 78.37 ± 4.35 Bqkg, 390.26 ± 76.37 to 733.61 ± 85.80 Bqkg, respectively where as for soil samples the values were 26.11 ± 2.99 to 61.66 ± 5.88 Bqkg, 41.93 ± 4.18 to 89.39 ± 6.15 Bqkg and 467.16 ± 77.62 to 1304.11 ± 147.07 Bqkg respectively. The calculated average absorbed dose rates due to these radionuclides in the three types of samples were found as 52.24 nGyh, 62.96 nGyh, and 104.97 nGyh, respectively. The estimated outdoor annual effective dose ranged from 0.05 to 0.08 mSvy, 0.05 to 0.11 mSvy and 0.07 to 0.17 mSvy with the mean values of 0.06 mSvy, 0.08 mSvy, and 0.13 mSvy for sand, sediment, and soil samples, respectively. The values of radium equivalent activity in almost all the samples were less than 370 Bq.kg. On the other hand, the values of external hazard index for sand, sediment, and soil samples varied between 0.22 to 0.37, 0.25 to 0.54, and 0.33 to 0.78 with the average values of 0.30, 0.37, and 0.59, respectively. The values are less than unity in all the samples that indicate the non-hazardous nature of the samples.