Natural radionuclide measurement and radioactivity assessment of soil samples in Gansu Province (China)

This investigation assessed the activity concentrations of natural radionuclides (Th-232, Ra-226, and K-40) within soil matrices across Gansu Province, China. A total of 115 soil specimens were gathered from agricultural lands and uncultivated sites. Samples were analyzed by a low-background and high-purity germanium (HPGe) γ-ray spectrometer. The activity concentration of Th-232, Ra-226, and K-40 ranged from 9.7 to 56.0 Bq/kg, 19.4 to 99.3 Bq/kg, 349.5 to 713.1 Bq/kg, with mean values of 27.4 ± 6.3 Bq/kg, 45.9 ± 10.5 Bq/kg, 566.7 ± 64.8 Bq/kg, respectively. Derived radiological parameters included external hazard index (Hex) of 0.37, absorbed gamma dose rate (D) of 63.8 nGy/h, and annual effective dose rate (E) of 78.5 μSv/a. This is the first time to evaluate the risk of natural radionuclides in soil in this area and provides essential information on the levels of background radiation in Gansu. The results indicate that the radioactivity level in the soil of Gansu is similar to that in Sichuan province, which borders Gansu and shares similar characteristics with the area. The natural radionuclide measurement and radioactivity assessment of soil samples in Gansu province show that they will not cause a significant threat to local residents.