The study has been carried out to measure the activity concentration of natural and anthropogenic radionuclides in fifteen(15) soil samples of Natore, Kushtia and Pabna district, which are around the 30 km peripheral area of Rooppur Nuclear Power Plant, by gamma ray spectrometry system using a High Purity Germanium (HPGe) detector. It is found that the activity concentration of 226 Ra, in the collected sample was from 3.52 Bq/kg to 28.5 Bq/kg with the average value of 12.42 Bq/kg. For 232 Th, the range was from 4.18 Bq/kg to 34.5 Bq/kg with the average value of 12.6 Bq/kg. Finally, the activity concentration of 40 K, in the collected sample was in the range of 84 Bq/kg to 345 Bq/kg, and the average value was 198.9 Bq/kg. The absorbed dose rate (D) was found to be in the range of 4.59 nGy/h to 40.93 nGy/h with the mean value 21.3 nGy/h. The annual effective dose (E) was in the range of 0.006 mSv/yr to 0.152 mSv/yr with an average of 0.033 mSv/yr. The radium equivalent activity was in the range from 10.02 Bq/kg to 89 Bq/kg with an average of 44.99 Bq/kg. The external hazard index (Hex) was found to be in the range of 0.027 to 0.242 with the mean value of 0.121 and the internal hazard index (Hin) was found to be in the range of 0.044 to 0.302 with the mean value of 0.156. All the values are much below the recommended limit by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 35 Bq/kg for 226 Ra, 30 Bq/kg for 232 Th and 400 Bq/kg for 40 K. According to international and national regulation, the annual dose to members of the public, 1and Hex & Hin must be lower than unity. Moreover, no artificial radioactivity was found in the soil samples of this study area. This research concludes that the found values are within the permissible limits as required by the Nuclear Safety and Radiation Control(NSRC) Rules-1997 of Bangladesh and International Atomic Energy Agency(IAEA) Safety Standards-General Safety Requirements (GSR): Part-3.

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Water is the most important source of life and ground water may contain varying levels of radioactivity. So it is therefore important to measure radon concentration in ground water for public health and radiation protection. In this study, radon concentration was measured in ground water samples collected from water pumps of different locations at Dhaka city, Bangladesh. Twenty ground water samples were collected in July 2017to April 2018 for radon level measurement. Radon detector RAD7 (manufactured by Durridge Company, USA) with RAD H2O technique was used for the measurement. The highest radon concentration was found 13.00±0.70 Bq/L for the pump of sample ID GW1 and the lowest radon concentration 2.13±0.593 Bq/L for the pump of sample ID GW10.The activity concentration of radon in maximum water samples in Dhaka city was lower than the value 11.1 Bq/L recommended by United States Environmental Protection Agency (USEPA). The radon concentration was lowered from the activity concentration before storage. The highest value of annual effective dose for radon in ground water was found 0.04745 mSv/y According to recommendation of World Health Organization, the annual effective dose level for radon in drinking water is 0.1 mSv/y. These results indicate that there is no probability of health hazards for public due to presences of radon in ground water and it is safe for consumption.

Sixteen samples in three categories vegetables, cereals (rice, wheat, maize, pulse) and powdered milk were collected from local markets (Dhaka city) in Bangladesh and analyzed by using High Purity Germanium (HPGe) Detector for the assessment of natural and artificial radioactivity. In vegetables (potato, raw banana, giant taro, red amaranth), the average activity concentrations of 232 Th, 226 Ra, and 40 K were found to be 37.82±11.57, 54.93±9.98 and 617.43±65.69 Bqkg -1 respectively, for cereals (rice, wheat, maize, pulse) 24.01±3.67, 31.46±4.00 and 474.83±27.68 Bqkg -1 respectively and for milk samples 15.01±3.65, 26.73±6.77 and 494.21±38.71 Bqkg -1 respectively. The average values of outdoor annual effective dose were found to be 92.18, 61.19 and 52.37µSvy -1 in vegetables, cereals and milk samples respectively. No artificial radionuclide was found in any of these samples. The average value of radium equivalent activity in all samples was 113.89 Bqkg -1 which was less than maximum permissible value 370 Bqkg -1 . The values of external hazard indices for vegetables, cereals and milk samples varied from 0.31 to 0.66, 0.17 to 0.40 and 0.11 to 0.36 respectively which is less than unity in all samples that indicate the non-hazardous nature of the samples. The average values of annual effective ingestion dose rate from foods (for adult) were 274.33 µSvy -1 , 533.60µSvy -1 , and 132.73µSvy -1 for 232 Th, 226 Ra and 40 K respectively. These data would be useful to establish a baseline for natural radioactivity concentrations in food items consumed in Bangladesh.

The radioactivity of naturally occurring radionuclides 226Ra, 232Th, and 40K was determined in thirteen cement samples collected from different manufactures of Dhaka city. The measurement was performed by gammaray spectrometry system using high purity germanium (HPGe) detector. The average activity of 226Ra, 232Th, and 40K in cement samples are fon und to be 30.23±15.04 Bqkg-1, 20.10±11.76 Bqkg-1 and 145.27±24.14 Bqkg-1, respectively. The average values of radium equivalent activity (Raeq), absorbed dose rates (D), internal hazard and external hazard index (Hex), and annual effective dose equivalent are 370 Bqkg-1, 0.27, 0.18, and 27.99 nGyh-1, respectively. The average annual effective dose is found 0.13 mSvy-1, which is less than the recommended value (1 mSvy-1) by the International Commission on Radiological Protection (ICRP-60, 1990), as the maximum permissible annual effective dose to the members of the public. The present study results are discussed and compared with those reported in similar studies and with internationally recommended values. No artificial radioactivity was found in the present study. The results show that the analyzed cement samples do not pose any significant radiation hazard from naturally occurring radionuclides 226Ra, 232Th and 40K reported here and also considered safe for use in buildings construction. J. Bangladesh Acad. Sci. 45(1); 95-104: June 2021