phytoremediation of uranium-238 and thorium-232 in contaminated soils using native dryland shrubs

Introduction: this study investigated the phytoremediation potential of atriplex canescens, haloxylon aphyllum, and nitraria schoberi for decontaminating soil polluted with radioactive elements.materials and methods: contaminated soil was collected from a uranium mine site. compost and sawdust were used as soil amendments. radionuclide activities and concentrations were determined using gamma spectrometry and icp-ms.results: h. aphyllum demonstrated the highest uptake of radioactive elements, accumulating 58 mg.kg-1 of th-232 and 28.08 mg.kg-1 of u-238, respectively. considering their initial concentrations, the thorium removal efficiency was higher than that of uranium, with a maximum of 85% for th-232 achieved by h. aphyllum. plant roots accumulated higher concentrations of radionuclides than the stems. a comparison of phytoremediation factors (tf, baf, and bcf) indicated that h. aphyllum had a greater stabilization potential than the other two species. furthermore, phytoextraction was identified as the dominant remediation mechanism.conclusion: compost application enhanced the phytostabilization potential of all three plants (e.g., as indicated by the increase in bcf, which reached a maximum of 0.45 for h. aphyllum). in contrast, sawdust had an inhibitory effect, likely due to the disruption of the c/n ratio, which prevented plant growth. h. aphyllum showed significant potential for radioactive soil rehabilitation, particularly when it was amended with compost.