Study on Probable Radionuclide Contents and Their Dose Assessment in Sand, Soil and Water Samples Collected from The Rupsha River, Khulna

Abstract

The radionuclide contents and their activity concentrations in soil, sediment and water samples collected from in and around of Rupsha River, Khulna, Bangladesh have been determined by using a High Resolution Germanium detector (HPGe) of 20% relative efficiency. A total of 44 samples of three categories were collected and analyzed. The activity concentrations of 226Ra, 232Th and 40K in the soil samples of the Rupsha River side area have been found to be varied from 42.99 ± 8.60 to 53.92 ± 7.86 BqKg-1, 64.90 ± 6.60 to 94.16 ± 6.74 BqKg-1 and 581.02 ± 77.66 to 1098.50 ± 124.90 BqKg-1 respectively with an average value of 50.16 ± 7.20 BqKg-1, 77.23 ±7.43 BqKg-1 and 864.63 ± 101.69 BqKg-1 respectively. For sediment samples the activity concentrations of the corresponding radionuclides ranged between 40.86 ± 4.31 to 58.27 ± 5.23 BqKg-1, 57.60 ± 6.84 to 82.78 ± 7.50 BqKg-1, 578.39 ± 74.62 to 1038.69 ± 110.70 BqKg-1 respectively with an average value of 50.46 ± 6.20 Bq/Kg, 73.99 ± 7.56 BqKg-1and 881.49 ± 100.25 BqKg-1 respectively. The results for both the soil and sediment samples obtained for the corresponding nuclides are slightly higher than the worldwide average values of 35, 30 and 400 BqKg-1. The activity contents of the water samples did not show any evidence of enhancement. The calculated average absorbed dose rates due to these radionuclides in soil and sediment samples have been found as 106.13 nGyh-1 and 105.03 nGyh-1, respectively which is higher than worldwide average values. The estimated outdoor annual effective dose ranged from 0.11 to 0.14 mSvy-1 and 0.10 to 0.14 mSvy-1 with the mean values of 0.13 mSvy-1 and 0.13 mSvy-1 for soil and sediment samples, respectively. The values of radium equivalent activity in almost all the samples were less than 370 BqKg-1. On the other hand, the values of external hazard index for soil and sediment samples varied between 0.52 to 0.67 and 0.49 to 0.67 with the average values of 0.61 and 0.61, respectively. The values are less than unity in all the samples that indicate the nonhazardous nature of the samples and there is no possibility of immediate health effect on the workers, public and environment