Evaluation of the Effect of Color on the Natural Radioactivity of Marble Collected from Zahedan and Zabol Cities

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Fatemeh Zakieh Tohid, Hadi Nakhzari Moghadam, Masoume Farsizaban, Zeinab Yazdi Sotoodeh, Vida Sargazi


Background: Humans in their environment are always exposed to radiation from various sources, including that of building materials. Since they spend about 80% of their time in enclosed environments, the probability of radiation is high.

Objectives: This dosimetric study was carried on marble stones used in buildings of Zahedan and Zabol cities in 2020. The purpose was to determine the relationship between stone color and its radioactivity.

Methods: For the purpose of the study, the researchers identified and prepared a list of supplied building stones in stone shops of Zahedan and Zabol cities during December 2020 to December 2021. A total including 75 marble samples, were collected by an MKS pen dosimeter in three operating modes: gamma equivalent dose rate (EDR) measured in microsievert per hour, equivalent gamma dose (ED) calculated in milliseconds, and beta flux density, measured in parts per square centimeter per minute (part/cm2.min).

Results: The highest EDR mean in marble stones belonged to white marble (0.13 μSv/h), while the lowest was found in cream-colored marbles (0.06 μSv/h). White samples had the highest mean of beta flux density in marble stones, 0.0026 part/cm2.min. The beta flux density equaled zero in five samples of marble. The ED value for all samples was set to zero.

Conclusion: The maximum amount of EDR and beta flux for marble stones concerned white color, which was slightly higher than the global average. The average EDR for travertine was slightly more than that of marble and the permissible limit. Also, the beta flux in marble stones, between 0.0016 and 0.0026, was higher than travertine stones, which is less than the allowable limit. The mean value of beta beam flux density in the open air was zero. In all samples, the amount of ED was zero. The amount of background radiation in the open air of Zahedan and Zabol cities corresponds to its average value in the world.

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