Assessment of natural radioactivity levels and radiological hazards in building materials commonly used in Ethiopian constructions

ABSTRACT

Natural radionuclide activity concentrations were measured in ceramic, gypsum, and brick samples from manufacturers, dealers, and construction sites in and around Addis Ababa, Ethiopia, using an HPGe detector. The study’s main aim is to assess the activity concentration of building materials and their health impacts. Average activity concentrations (Bq kg⁻¹) for ²²⁶Ra in ceramic, gypsum, and brick samples were obtained as 81 ± 1, 1.34 ± 0.17, and 39 ± 1, respectively. In ceramic, gypsum, and brick, concentrations of ²³²Th were obtained as 166 ± 4, 0.68 ± 0.18, and 103 ± 3, respectively, while concentrations of ⁴⁰K were found to be 755 ± 16,15 ± 1, and 921 ± 24, respectively. Some of the materials that were tested, especially the ceramic samples, had slightly higher concentrations of radionuclides in comparison to other analysed samples. In all samples except ceramic, Ra_eq was < 370 Bq kg⁻¹, which is the recommended limiting dose for bulk medium. Furthermore, the corresponding radiological parameters, such as absorbed dose, annual effective dose equivalent, excess lifetime cancer risk (ELCR), internal (H_in) and external (H_ex) hazard indexes, gamma index (Iγ), and alpha index (Iα) were determined. The ELCR average values in this study are slightly higher than the global average, and the indoor and outdoor absorbed dose rates are greater than the limiting criteria of 84 and 59 n Gy h⁻¹, respectively. Therefore, it is important to assess the potential radiation risk of ceramic samples, which should be used in a controlled manner to reduce gamma exposure to residents. Finally, the computed data could be used as a baseline to assess any future radiation exposure from construction materials.

KEYWORDS:

• Building materials
• activity concentration
• natural radionuclides
• HPGe detector
• construction sites
• Ethiopia

Acknowledgments

The authors would like to express their gratitude to the Ethiopian Radiation Protection Authority for allowing them to use their HPGe detection system and research laboratory head, Mr. Eshitu, and Mrs. Bogalech, for their cooperative and helping to do my experimental work for this study. We are also grateful to Addis Ababa University’s Department of Physics for assisting us with this project.

Data availability statement

Additional data supporting the study’s findings are available in the supplementary information file and upon request to the corresponding author. https://doi.org/10.5281/zenodo.6419855

Disclosure statement

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

Additional information

Notes on contributors

Desalegn Ketema Gebremeskel

Desalegn Ketema performed data collection, preparation, and measurement, as well as analytic computations and data analysis interpretation. Desalegn Ketema, Tilahun Tesfaye and Ashok. K. Chaubey contributed significantly, directly and intellectually to the final version of the manuscript. Tilahun Tesfaye supervised the project.