RESUMO
Objective To evaluate the current situation of radioactive contamination in the soil around a decommissioned uranium mine by combined determination of 210Pb and 210Po activity concentrations. Methods Soil samples were collected around a decommissioned uranium mine. 210Po and the 210Pb decay product 210Bi were plated on a copper sheet by self-deposition at a constant temperature. Gross α and gross β counts were measured using a low-background α/β counter. The activity concentrations of 210Pb and 210Po in soil were calculated. The radioactive contamination was evaluated using geological accumulation index. Results The activity concentrations of 210Pb and 210Po in the soil around the decommissioned uranium mine were 873.7-2315.5 and 956.0-2315 Bq·kg−1, respectively. The activity concentrations of 210Pb and 210Po in nearby farmland soil were 54.2-257.8 and 59.1-234.5 Bq·kg−1, respectively. Evaluation with the geological accumulation index showed that the level of nearby farmland contamination was 0-2, indicating zero to moderate radioactive contamination of the farmland. Conclusion The relatively high radioactivity around the decommissioned uranium mine requires attention to the transfer, diffusion, and ingestion of the uranium decay products 210Pb and 210Po in the surrounding soil to avoid radioactive contamination of the environment.