Assessment of the radiological status of the Bahi wetlands in Dodoma region

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University of Dar es Salaam
The activity concentrations of 226Ra, 232Th and 40K in soil, water and sediment samples collected from different areas in Bahi wetlands have been measured by gamma-ray spectrometry to assess radiological status of the area. The average concentrations of radionuclides in soil samples varied from 23.4±0.5 to 37.0±0.7 Bqkg-1 for 226Ra, 25.8±0.5 to 51.0±0.9 Bqkg-1 for 232Th, and 368±4 to 875±9 Bqkg-1 for 40K. In water samples, the activity concentrations of 226Ra were below the detection limit (0.11 Bql-1) for the system used in this study. The average concentrations of 232Th and 40K in domestic water were found to be 0.68±0.02 and 2.82±0.03 Bql-1 with maximum values of 0.740±0.003 and 4.36±0.05 Bql-1, respectively. The average concentrations in sediment samples varied from 27.1±0.5 to 64.7±1.3 Bqkg-1, 37.3±0.7 to 54.3±1.1 Bqkg-1 and 460±5 to 807±9 Bqkg-1 for 226Ra, 232Th and 40K, respectively. The average radioactivity concentrations for 226Ra (37 Bqkg-1), 232Th (51 Bqkg-1), and 40K (875 Bqkg-1) obtained in soil samples from Northern Zone (NZ) were higher than the world average values reported by UNSCEAR, 2000. The average concentrations of 226Ra and 232Th in drinking water samples from the study area were found to be lower than the guidance levels of these radionuclides (1 Bql-1 for 226Ra and 232Th) in drinking water recommended by the WHO. The calculated total annual effective dose equivalent from radionuclides concentrations in the soil was found to be less than the annual dose limit of 1 mSv recommended by the ICRP for public exposure control. Moreover the radiological hazards to population assessed based on calculations of radium equivalent activity (Raeq) and external hazard index (Hex) were found to be lower than 370 Bqkg-1 and unity, respectively; indicating the insignificant of the radiation hazards in the area.
Available in print form, East Africana Collection, Dr. Wilbert Chagula Library, Class mark (THS EAF QC795.55.U7K55 )
Radioactivity, Environmental aspects, Bahi wetlands, Dodoma region, Tanzania
Kimaro, E. E (2014) Assessment of the radiological status of the Bahi wetlands in Dodoma region, Master dissertation, University of Dar es Salaam. Dar es Salaam.