Evaluation of Radioactivity Levels in Soil Samples from Assosa City in Benishangul Gumuz Region, Ethiopia

Abstract

The specific activity concentrations of naturally occurring radionuclides in soil samples collected from suburban areas of Assosa City was measured using a High purity Germanium (HPGe) detector. The average specific activity concentrations of ²³⁸U and ²³²Th exceed the recommended safe value of 35.0 and 30.0 Bq kg⁻¹, respectively. For ⁴⁰K, the average activity concentration is below the recommended safe value of 400.0 Bq kg⁻¹. The calculated mean value of the absorbed dose rate is 72.8 ± 3.72 nGy h⁻¹ which exceed the recommended safe value of 59 nGy h⁻¹. The calculated mean annual effective dose equivalent values for indoor and outdoor are 2.11 ± 0.1 mSv y⁻¹ and 0.52 ± 0.02 mSv y⁻¹, respectively. The calculated mean values of the internal hazard index, external hazard index, and gamma index are 0.43 ± 0.013, 0.56 ± 0.01, and 0.5 ± 0.01, respectively, and those values are below the recommended safe value of one. The mean value of excessive lifetime cancer risk is above the threshold value of 0.29 × 10⁻³. From this study, it is recommended that Assosa soil needs further investigations.

Keywords:

• Assosa
• detector
• health
• gamma-ray
• radionuclide
• soil

Acknowledgments

I would like to thank, Assosa University and Addis Ababa University for supporting my research, Ethiopian Conformity Assessment Enterprise staff members, and Ethiopia Radiation Protection Authority for the experimental work using HPGe detector.

Author Contributions

Yared Birhane has done sample preparation, data analysis, data interpretation, and manuscript writing. Yared Birhane and Dr. Tilahun Tesfaye have contributed to the study’s conception and design. Both Yared Birhane and Guadie Degu have contributed to the selection of the study area and sample collection.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Data Availability Statement

There will be data available upon reasonable request to the corresponding author.