Assessment of levels spatiotemporal differences and health risks of environmental radioactivity in the soil of Chongqing China

This study investigated the spatio-temporal variations of soil radionuclides in Chongqing (2016–2023) and assessed their associated health risks. Using descriptive, correlation, and mixed-effects model analyses, the activity concentrations and distribution of soil radionuclides (137Cs, 238U, ²³²Th, 226Ra and40 K) were examined. AEDE, Raeq, ELCR, ADR were calculated. Spatially, after controlling for temporal variation, the Urban New Area showed higher 226Ra and 238U than the Urban Core Area, while the Southeast Wuling Mountain Area had higher 226Ra, 137Cs and 238U. Temporally, after controlling for regional variation, 40K (2023, 2021), ²³²Th (2018–2023) and 238U (2021) all exhibited higher activity concentrations than in 2016. The calculated health risk indices (AEDE, Raeq, ELCR, ADR) were above global averages, indicating a need for targeted soil management. Specifically, levels of 226Ra and 238U in the Urban New Area, and of 226Ra, 137Cs, 232Th and 238U in the Southeast Wuling Mountain Area, require prioritization.