Natural radioactivity and radiological risks of common building materials used in Semnan Province dwellings, Iran

Impact assessment of building materials is a focused topic in the field of radioecology. A radiological survey has conducted to monitor radioactivity of most common building materials in Semnan Province, Iran, and assess the radiation risk. Activity concentrations of Ra-226, Th-232, and K-40 were measured in 29 samples including nine commonly used building materials that were collected from local suppliers and manufacturers, using a high purity germanium gamma-ray detector. The activity concentrations of Ra-226, Th-232, and K-40 varied from 6.7 +/- 1 to 43.6 +/- 9, 5.9 +/- 1 to 60 +/- 11, and 28.5 +/- 3 to 1085 +/- 113 Bq kg(-1) with averages of 26.8 +/- 5, 22.7 +/- 4, and 322.4 +/- 4 Bq kg(-1), respectively. By applying multivariate statistical approach (Pearson correlation, cluster, and principal component analyses (PCA)), the radiological health hazard parameters were analyzed to obtain similarities and correlations between the various samples. The Pearson correlation showed that the Ra-226 distribution in the samples is controlled by changing the Th-232 concentration. The variance of 95.58% obtained from PCA resulted that the main radiological health hazard parameters exist due to the concentration of Ra-226 and Th-232. The resulting dendrogram of cluster analysis also shows a well coincidence with the correlation analysis.