A global meta-analysis of radiological contamination in soils and Monte Carlo simulation-oriented hazards evaluation

Soil pollution caused by radionuclides has become a global concern. However, previous research has mostly focused on specific sites or limited locations, which may not provide a comprehensive understanding of the overall soil pollution situation worldwide. To address this gap, this study collected and examined data from published articles between 2010 and 2023. The research examined levels of 226Ra, 232 Th, 40K, 238U, and 137Cs in soils globally and used meta-analysis to assess the radiological hazards and health risks associated with radio-nuclide contamination. The average content of 226Ra, 232Th, 40K, and 238U was significantly higher than the permissible values, by approximately 4.21, 3.80, 1.20, and 9.78 times, respectively. The studied soils were found to have moderate to heavy contamination levels of 226Ra, 232Th, and 238U based on the geoaccumulation index. Additionally, they exhibited heavy contamination with 40K. Several radiological hazard indices, such as the internal hazard index (Hin), absorbed gamma dose rates (Dout and Din), annual effective dose rates (Eaed out and Eaed in), activity utilization index (AUI), and excess lifetime cancer risk (ELCRout and ELCRin), were higher than recommended limits. Monte Carlo simulation-based analysis revealed elevated radiological risks, with the 95th percentile values for Raeq, Dout, Din, ELCRout, and ELCRin exceeding respective threshold values. These findings provide valuable insights for policymakers to develop effective strategies for minimizing global exposure to radionuclides in soil.