Natural radioactivity measurements and dose rate assessment of selected ceramic and cement types used in Riyadh, Saudi Arabia

Abstract

The natural radioactivity of ceramic and cement samples collected from Riyadh, Saudi Arabia, was analyzed using a gamma-ray spectrometry system with a high-purity germanium detector. The specific activities of 226Ra, 232Th, and 40K ranged from 45.0 ± 4.2 to 177.8 ± 7.5 Bq/kg, 49.1 ± 2.6 to 228.4 ± 6.8 Bq/kg, and 370.0 ± 5.3 to 1269.0 ± 12.2 Bq/kg, respectively, for the ceramic samples and from 11.4 ± 2.0 to 28.7 ± 5.3 Bq/kg, 8.4 ± 1.3 to 10.8 ± 1.1 Bq/kg, and 50.7 ± 2.1 to 209.7 ± 3.5 Bq/kg, respectively, for the cement samples. The radium equivalent activity, external hazard index, absorbed dose rate, and annual effective dose were calculated using the above measurements in order to assess the radiological hazard associated with the studied building materials. The average values of these radiological indices for the ceramic samples were 299.4 ± 94.8 Bq/kg, 0.8 ± 0.3, 138 ± 42.4 nGy/h, and 0.68 ± 0.21 mSv/y, respectively, and for the cement samples, these values were 36.8 ± 7.74 Bq/kg, 0.12 ± 0.02, 20.35 ± 4.39 nGy/h, and 0.10 ± 0.02 mSv/y, respectively. The radiological indices of the studied samples were found to be within the range of those reported in recent similar studies conducted in other countries. The majority of the ceramic samples can be safely used as building materials for dwelling construction, although some samples slightly exceeded the average radium equivalent of 370 Bq/kg and the external hazard index limit of 1; the hazard indices for the cement samples, however, were all below the recommended world limits and can be considered safe for inhabitants.