Assessing Radiological Risks of Natural Radionuclides on Sustainable Campus Environment

Soil samples were collected from a college campus in Taiwan to measure the levels of radionuclides, contributing to the sustainable management of campus environments. A high-resolution HPGe gamma spectrometry system was utilized to measure the activity concentrations of natural radionuclides ( 226 Ra, 232 Th, and 40 K) and artificial radionuclide ( 137 Cs). The activity concentrations of 137 Cs were not detected in the campus soils, suggesting that artificial radionuclides did not contaminate the soil, supporting sustainable soil quality. However, the average concentrations of 232 Th and 40 K with mean values of 53.4 ± 5.1 and 504.5 ± 75.4 Bq/kg dw were higher than the global soil average of 45 and 420 Bq/kg dw, respectively. Meanwhile, the average concentration of 226 Ra with a mean value of 30.1 ± 3.0 Bq/kg dw was similar to the global soil average of 32 Bq/kg. The average outdoor absorbed gamma dose rate (D ex ) and annual effective doses (AED ex ), with a mean of 67.2 nGy/h and 82.4 μSv/y, were found to be higher than the average world levels of 57 nGy/h and 70 μSv/y, respectively. Despite these findings, the radium equivalent activity Ra eq and external hazard index H ex , with average values of 145.2 Bq/kg and 0.39, respectively, were below the recommended limit values of 370 Bq/kg and 1.0, respectively. This study provides useful information on the background radioactivity of the study campus, which is crucial for developing sustainable strategies to ensure a safe and healthy environment, indicating that there are no radiological hazards in the soil.