Evaluation of Natural Radioactivity Levels and Potential Radiological Hazards of Common Building Materials Utilized in Mediterranean Region, Turkey

Radiometric measurement of building materials is very important to assess the internal and external exposure caused by the ionizing radiation emitted from terrestrial radionuclides in building materials. The activity concentrations of 226Ra, 232Th, and 40K in fifty-eight samples of fifteen different structural and covering building materials commonly used in Osmaniye province located in the Mediterranean region of Turkey were measured by using gamma-ray spectroscopy. The activity concentrations of 226Ra, 232Th and 40K varied from 2.5 ± 0.1 (marble) to 145.7 ± 4.4 (clay brick), 1.3 ± 0.1 (marble) to 154.3 ± 4.1 (marble) and 8.6 ± 0.2 (sand) to 1044.1 ± 70.3 (granite), respectively. Radiological parameters (activity concentration index, alpha index, indoor absorbed gamma dose rate and the corresponding annual effective dose rate, and excess lifetime cancer risk) were estimated to evaluate the health hazards associated with these building materials. Since the estimated values of these parameters are within the recommended safety limits or criteria values, the use of the studied building materials in the construction of dwellings can be considered to be safe for the residents of the region.

Elevated concentrations of terrestrial radionuclides in sand: An essential raw material used in Bangladeshi dwellings

Sand is one of the main materials used in the construction industry. Elevated concentrations of terrestrial radionuclides in sand may cause great harm to dwellers. Present study determines concentrations of terrestrial radionuclides in sand that is widely used as a raw material in the construction industry in Bangladesh, via conventional HPGe γ-ray spectrometry. The average activity concentrations of 226Ra, 232Th and 40K in the analysed samples were found as 36.8 ± 3.9, 58.9 ± 6.0 and 755 ± 91 Bqkg−1 in Base sand, 68.1 ± 5.3, 185.7 ± 9.9 and 1032 ± 104 Bqkg−1 in Sylhet sand, and 38.1 ± 3.6, 74.7 ± 5.9 and 636 ± 77 Bqkg−1 in Aster sand. All data show relatively higher values than the world average of 35, 30, 400 Bqkg−1, respectively. Key hazard parameters were estimated to realize the radiation effects on human health due to the use of sand as construction and building materials. The estimated parameters for Sylhet sand show relatively higher values than the population-weighted world average values, prescribed by regulatory bodies. Results show that the Sylhet sand may pose a significant radiation hazard to the dwellers via prolonged exposure, and necessary precautionary steps need to be taken to ensure safe dwellings while using this sand for construction and decorative purposes.

HUMAN EXPOSURE TO BACKGROUND RADIATION IN ORTUM, KENYA

The activity concentration of radionuclides 238U, 232Th and 40K in soil and the absorbed dose rate (ADRA) at 1 m above the ground in Ortum was determined. The activity concentration in soils ranged from 33 to 85, 20 to 67 and 148–1019 Bq kg–1, respectively with an average of 40 ± 1.43, 56 ± 1.46 and 425 ± 19.24 Bq kg–1, respectively. The activity concentration of 232Th and 238U was found to reduce with increasing depth while that of 40K increased with increasing depth. The average activity concentration in soil was higher than the world average values. The average ADRA in air at 1 m above the ground was found to be 112 ± 29.6 nGy h–1. The soil and rocks in Ortum are recommended for use because the activity concentration of the terrestrial radionuclides is lower than the recommended threshold values.

Analysis of specific radionuclides activity variations in soil within geotectonic units of Republic of North Macedonia

To establish baseline values for concentrations of terrestrial radionuclides for the Republic of North Macedonia, a survey covering the entire territory was performed. The 213 soil samples were collected from regions around the major settlements and cities, approximately evenly distributed over the geotectonic units which constitute the country's geological foundation. The specific activities of radionuclides were measured by gamma spectrometry. The following geometric mean values and geometric standard deviations were obtained: 550 Bqkg?1 (1.47) for 40K, 37 Bqkg?1 (1.53) for 226Ra, 38 Bqkg?1 for 238U, and 38 Bqkg?1 (1.53) for 232Th in dry soil. The relation between specific activities of natural radionuclides and geology was investigated. Correlation between radionuclides, which may serve as additional geochemical indicators, and geology could not be found convincingly. Mutual correlations between 226Ra, 238U, and 232Th activities were found to be high (Spearman ? about 0.8), whereas the ones between these and 40K are a bit lower, somewhat above ?= 0.6. <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/NTRP1902209E">10.2298/NTRP1902209E</a><u></b></font>