Radiometric assessment of the sewage treatment site at Ahmadu Bello University, Zaria

Abstract

The radiometric assessment of Ahmadu Bello University's sewage treatment site in Zaria was conducted in three profiles along two  ponds in the research region. The goal is to estimate the concentration and dose rate of naturally occurring radioactive elements, as well  as to assess the risk to workers in the area. Gamma-ray  spectrometer alongside with GPS (global positioning system) were used.  The concentration of ²³⁸U, ²³²Th and ⁴⁰K were contour to show the areas of high concentration of the radionuclide. The data were taken at 5 m interval in each profile along the sewage ponds. The data collected were interpreted using the golden software  surfer 16. The  concentration of the radionuclide ²³⁸U, ²³²Th and ⁴⁰K in the study area were found to be between the range of 2 ppm - 21 ppm which is  equivalent to the activity levels of 22.2 Bq/kg - 233.1 Bq/kg for ²³⁸U, 14.5 232 ppm - 29.5 ppm which is equivalent to the activity levels of 58.87  Bq/kg - 119.77 Bq/kg for ²³²Th and 2.5% - 40 10.5% which is equivalent to the activity levels of 782.5 Bq/kg - 3286.5 Bq/kg for ⁴⁰K  respectively. The dose rate of the radionuclide U, ²³²Th and ⁴⁰K in the study area were 11.35 nGy/h - 119.18 nGy/h for ²³⁸U, 36.16  nGy/h -  73.57nGy/h for ²³²Th and 32.69 nGy/h - 137.29 nGy/h for K respectively. The total count and absorb dose spanned within the  range of 330 - 395 cps and 115 - 200 nGy/h respectively. The result show that the absorbed  dose rate of the radionuclide ( ²³⁸U,  ²³²Th and ⁴⁰K) and total absorbed dose rate are above world average.