Multivariate statistical analysis correlating 238U, 232Th, and 40K equivalent activities in soil to geochemical data from an agricultural area

Purpose Multivariate statistical analysis was used for the correlation of U-238, Th-232, and K-40 equivalent activities to geochemical data from soil samples collected at depths from 0 to 20 and 20 to 40 cm in an agricultural area. Materials and methods A total of 154 soil samples were used for determining radionuclide equivalent activities, pH, clay and organic matter contents, and available phosphorous, potassium, calcium, magnesium, copper, zinc, iron, and manganese concentrations. Results and discussion Activities ranged from 31.0 to 124 Bqkg(-1) for K-40, 2.50 to 20.9 Bqkg(-1) for U-238, and 0.40 to 17.1 Bqkg(-1) for Th-232. At depths from 0 to 20 cm, clay and organic matter contents ranged from 14.0 to 88.0 and 0.60 to 4.60%, respectively. Available phosphorous, potassium, calcium, magnesium, copper, zinc, iron, and manganese concentrations ranged from 1.80 to 80.0, 36.0 to 667, 40.1 to 1923, 12.1 to 328, 0.80 to 26.1, 0.50 to 23.5, 29.0 to 112, and 30.0 to 76.0 ppm, respectively. The pH at the same depths ranged from 5.70 to 7.20. At depths of 20 to 40 cm, these ranges were from 14.0 to 92.0 and 0.50 to 4.30%, and 1.00 to 60.0, 24.0 to 364, 60.1 to 2024, 12.2 to 328, 0.70 to 28.8, 0.50 to 21.3, 2.50 to 148, and 2.30 to 100 ppm, respectively. The pH at these depths ranged from 5.70 to 7.30. Conclusions Important correlations were found between radionuclide equivalent activities and geochemical data at both depths by multivariate statistical analysis.