Zhao Yan, Yao Jun, Sunahara Geoffrey, Yue Wei, Huang Peng, Duran Robert
School of Water Resources and Environment, Research Center of Environmental Science and Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, 100083, Beijing, China.
School of Water Resources and Environment, Research Center of Environmental Science and Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian District, 100083, Beijing, China.
J Environ Manage. 2025 Aug 17;393:126982. doi: 10.1016/j.jenvman.2025.126982.
Bioremediation is recognized as an eco-friendly, economical technology for mitigating heavy metal(loid) (HM) pollution in nonferrous metal mining areas. However, remediation strategies such as microbial acidification, oxidation, reduction and chelation, as well as phytoremediation based on adsorption and immobilization, are insufficient for the successful rehabilitation of polymetallic-contaminated mine sites. This study investigates the effects of combining microbial treatment and phytoremediation on tailings quality, HM migration and transformation, and plant growth using soil inoculation and potting experiments. Results showed that the P-, Si- and K-solubilizing plant growth-promoting bacteria (PGPB) enriched from nonferrous metal mine tailings improved the physico-chemical characteristics of the mine soil, enhanced HMs fixation, and favored the growth of rapeseed (Brassica napus). Compared to the control CKⅠ (no plants and uninoculated), PGPB significantly increased the contents (expressed as the range of average %) of available P (71.65-96.30), Si (12.22-37.41), and K (36.85-56.07) in soil under Cd, Pb, and Zn stress. Soil microbial metabolic activities (urease, sucrase, acid phosphatase activities, and microbial calorimetry) were increased, which improved the rapeseed chlorophyll and malondialdehyde content. PGPB inoculation also increased the USEPA Toxicity Characteristic Leaching Procedure output (range of average %) of Cd (20.75-34.84), Pb (23.10-40.74), and Zn (9.94-21.89) in the tailing's rhizosphere (p < 0.05) compared to the CKⅡ control (soil with plants but uninoculated), which was likely associated with the organic acids secreted by the PGPBs. Reduced toxicity in tailing leachates following PGPB treatment indicates that HMs were immobilized by rapeseed. This study provides theoretical knowledge for developing future phytoremediation and re-greening strategies for HM-contaminated mine sites.
