Estimation of natural radionuclides’ concentration of the plutonic rocks in the Sakarya zone, Turkey using multivariate statistical methods

The study aimed to determine the natural radioactivity levels of226Ra,232Th, and40K by the Gamma-Ray spectrometry method, and radiological hazard parameters of the plutonic rocks in the Western and Central Sakarya Zone and to analyze the data using multivariate statistical methods. The average radiological values of samples were determined as40K (1295.3 Bq kg−1) >232Th (132.1 Bq kg−1) >226Ra (119.7 Bq kg−1). According to the skewness values of the distributions of the examined radionuclides,226Ra (2.1) and232Th (0.7) seemed to be positively right-skewed while40K (−0.2) had a negatively right-skewed histogram. On the other hand, the following kurtosis values were calculated for the distributions:226Ra (5.8 > 3),232Th (−0.7), and40K (−0.8). Kolmogorov–Smirnov and Shapiro–Wilk tests were applied to the data to test their normality. Therefore, Spearman’s correlation coefficient method was performed. The radionuclides of226Ra and232Th were found to have a positive correlation with radiological hazard parameters of the samples. 2 (two)-related factors identified, and the cumulative value was calculated to be 98.7% on the basis of the Scree Plot. According to the hierarchical cluster analysis, the samples that are grouped with those from Camlik region are prominent. The average radioactivity values of Camlik, Sogukpinar, Karacabey, and Sogut (except for232Th) regions were detected to be higher than the world averages while the value of40K was also found to be higher than the average values of various countries in the world.