Natural radioactivity and ecological environment safety assessment in Jinzhou Economic and Technological Development Zone, Liaoning Province

Based on field survey of terrestrial natural radionuclides of ⁴⁰K, ²³²Th and ²³⁸U, this study analyzes the geological conditions, the influence of surface media on radioactivity and underlying causes in Jinzhou Economic and Technological Development Zone, and summarizes the natural radioactivity levels and their distribution patterns. The results show that the average specific activity of these radionuclides in the region are 810.83 Bq/kg, 38.58 Bq/kg, and 26.05 Bq/kg, respectively. Compared with published national and global terrestrial radionuclide concentrations, those of ²³⁸U and ²³²Th are relatively low, while that of ⁴⁰K is significantly higher. The average external exposure index is 0.41, with a median of 0.39, which is far below the national limit of 1 for external exposure index of building materials. The annual effective dose rate is 0.03-0.19 mSv/a, averagely 0.08 mSv/a, well below the International Commission on Radiological Protection (ICRP) recommended public exposure limit of 1.0 mSv per year. The assessment concludes that the overall radiation level in the study area is stably distributed, classifying it as an ecologically safe area in terms of radiation.