Assessment of gamma radiation levels and natural radioactivity in soils along a subtropical river basin, China

Abstract

Abstract The activities of natural radionuclides in the environment can be used to assess radiological effects. Monitoring the radiation level in soils is important for public health. It also has important geochemical implications as most of the sediment eroded from river basins is from soil. Therefore, we carried out a soil sampling campaign along a subtropical river basin in southeastern China (Jiulong River). Surface and depth profile soils were collected, and the natural radionuclide activities were measured. The activities of the natural radionuclides 238U, 232Th, and 40K in the surface soils varied from 31.6 to 132.1 Bq kg-dry−1, 37.8 to 174.0 Bq kg-dry−1, and 52.3 to 596.2 Bq kg-dry−1, with average values of 56.7±30.3 Bq kg-dry−1, 86.7±41.3 Bq kg-dry−1, and 352.8±190.6 Bq kg-dry−1, respectively. The absorbed gamma dose in air and the annual effective dose equivalent (AEDE) in surface soils along the river basin were both higher than the world average. In the depth profiles, excess 210Pb (210Pbex) decreased with depth and significant correlation between 210Pbex and TOC was observed, suggesting that they are affected by similar processes (leaching and sorption).