Determination of natural radioactivity levels and radiation hazards for natural gypsum in Abay gorge, Dejen district, Ethiopia

ABSTRACT

Natural gypsum has been studied as a building material, and it has been discovered that it is one of the potential sources of indoor radioactivity due to naturally occurring radioactive elements in it. The levels of radioactive elements obtained in natural gypsum available in Abay gorge Dejen district were accomplished by a well shielded and calibrated gamma spectrometry with high purity Ge detector to evaluate the radiation hazard to workers in Dejen gypsum factories and dwellers in buildings decorated with gypsum products. The results of this study revealed that radioactive elements ²³⁸U, ²³²Th, and ⁴⁰K are found in raw gypsum samples, with specific activity ranging from 1.47 ± 0.26 to 2.42 ± 0.37 Bqkg⁻¹, 1.10 ± 0.26 to 2.60 ± 0.48 Bqkg⁻¹, and 4.27 ± 1.92 to 44.53 ± 2.84 Bqkg⁻¹, respectively. The mean specific activities are 1.90 ± 0.33 Bqkg⁻¹ for ²³⁸U, 1.99 ± 0.39 Bqkg⁻¹ for ²³²Th, and 28.16 ± 2.57 Bqkg⁻¹ for ⁴⁰K, which are significantly lower than the intercontinental approved values. All of the calculated radioactive risk indices were significantly lower than the global recommended values for building materials. The values of various radioactive indices indicate that the use of gypsum powder obtained from studied samples in the construction of residences is considered safe.

KEYWORDS:

• Gypsum samples
• Abay gorge
• naturally occurring radionuclides
• gamma spectrometry
• radiological parameters

Acknowledgments

I would like to express my deepest gratitude to the representative of the five gypsum factories in Dejen, town Ethiopia for allowing me to collect samples. I am grateful to the Physics Department at Addis Ababa University for their cooperation and assistance in carrying out these experiments. I would like to give special thanks to Ethiopian Radiation Protection Authority (ERPA) for providing their full laboratory without any cost for this article.

Disclosure statement

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