Field Tests of the Phytoremediation of Uranium Tailings by Macleaya cordata (Willd.) R. Br.

The goal of this research is phytoremediation of uranium-contaminated soil. In the preliminary investigation, Macleaya cordata (Willd.) R. Br. was found to grow in abundance around uranium tailings. Afterward, the field tests to remove uranium from the contaminated soil by the M. cordata (Willd.) R. Br. were conducted. After 3 years of treatment, the contents of uranium in the shallow, middle, and deep layers decreased by 51.2%, 16.6%, and 90.3%, respectively, indicating the transfer of uranium from the tailings. The content of uranium in the roots, stems, and leaves of M. cordata that had been planted for 3 years was significantly higher than that in the first year, indicating the transfer of uranium to M. cordata (The uranium content of the part of M. cordata underground is 1.870 ± 0.288 mg/kg and the content in the aboveground part is 79.815 ± 0.911 mg/kg after 3 years). The results of Mi-Seq indicated that microbial communities were exposed to variations and that microbes, such as Bacillus, Lactococcus, Nitrosomonadaceae, and Roseiflexus, were involved in the remediation of uranium-contaminated soil, demonstrating that the reduced uranium content in the tailings is a result of the joint action by plants and microbes. An infrared analysis indicated that the -OH and COO- groups are the main functional groups in M. cordata involved in the bioconcentration of uranium. Moreover, as time advances, the uranium in the tailings was readily concentrated by the plant, demonstrating that the remediation of radioactive contamination by M. cordata is viable.