Rare earth elements (REE) in soils and plants of a uranium-REE mine site and exploration target in Central Queensland, Australia

Background and aims Investigations on the biogeochemical behaviour of rare earth elements (REEs) in natural systems broaden our understanding on their occurrence and fate in ecosystems. The aim of this study was to assess the prevailing REE concentration patterns in soils and plants in a uranium REE-rich area in Central Queensland, Australia. Methods We collected and analysed matching soil and plant material samples from both undisturbed and mine-affected areas enriched in REEs near the now abandoned Mary Kathleen Mine. Results We found that in the soil, Ce had the highest concentrations (1550 μg g −1 ), followed by La (645 μg g −1 ), whereas that of Gd (25 μg g −1 ) and Lu (1.5 μg g −1 ) were comparatively low. Soil REE patterns had a slight HREE enrichment relative to LREE, with a positive Ce anomaly, suggesting oxidizing conditions. The REE patterns of the DTPA-extracts had LREE enrichment relative to HREE. Soil pH was negatively correlated with DTPA-REE (−0.68 ≤ R ≤ -0.40; p