Phytoremediation of Uranium-238 and Thorium-232 in Contaminated Soils Using Native Dryland Shrubs

Javad Rabee  Haghighi; Fahimeh  Teimouri; Asghar  Seddighzadeh; Asghar Mosleh  Arani; Ehsan  Abouee

doi:10.18502/jehsd.v10i3.19793

Javad Rabee Haghighi Environmental Sciences and Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Fahimeh Teimouri Environmental Sciences and Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Asghar Seddighzadeh Fusion Research Center, Atomic Energy Organization, Tehran, Iran.
Asghar Mosleh Arani Department of Environmental Sciences, Faculty of Natural Resources, Yazd University, Yazd, Iran.
Ehsan Abouee Environmental Sciences and Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.

DOI: https://doi.org/10.18502/jehsd.v10i3.19793

Keywords: Phytoremediation, Radioactive Waste, Uranium-238, Thorium-232, Soil, Composting,

Abstract

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.