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| Efficiencies and microbial mechanisms of root exudate regulation on the phytoremediation of antibiotic-heavy metal polluted sediment |
| Received:May 12, 2025 |
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| KeyWord:root exudates;antibiotics;heavy metals;sediments;phytoremediation;microbial community structure |
| Author Name | Affiliation | E-mail | | LU Yebin | Power China Huadong Engineering Corporation Limited, Hangzhou 311122, China | | | ZHANG Xueqi | Institute of Eco-environmental Engineering, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China | | | QI Shiying | Power China Huadong Engineering Corporation Limited, Hangzhou 311122, China | | | HAN Shanrui | Power China Huadong Engineering Corporation Limited, Hangzhou 311122, China | | | LI Wei | Power China Huadong Engineering Corporation Limited, Hangzhou 311122, China | | | XU Ling'e | Power China Huadong Engineering Corporation Limited, Hangzhou 311122, China | | | CHENG Shuiping | Institute of Eco-environmental Engineering, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Shanghai Engineering Research Center of LandsCape Water Environment, Shanghai 200031, China | shpcheng@tongji.edu.cn |
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| Abstract: |
| Antibiotics and heavy metals from aquaculture that are not fully treated are discharged with wastewater and accumulate in sediments. To address this co-contamination issue, this study employed waterlogged pot experiments, adding oxytetracycline(OTC), copper (Cu), and zinc(Zn)to simulate composite-polluted sediments. Canna indica was selected as the remediation plant, with four exogenous root exudate doses(0, 5, 10, 15 mL·pot-1)to investigate their regulatory effects on remediation efficiency and microbial mechanisms, comparing pollutant removal efficiencies under plant-free and plant-combined conditions. Results demonstrated that plant combination significantly enhanced remediation: compared to plant-free groups, plant combination increased OTC removal by 4.8%–17.5% across all exudate doses, with optimal efficiency at 10 mL·pot-1(11.8%–17.5% increase vs. plant-free groups). For Cu and Zn, the 15 mL·pot-1 dose in plant-free groups significantly improved removal by 19.6% and 9.8%, respectively, while the 10 mL·pot-1 dose under plant-combined conditions yielded the best results. At this dose, the bioavailable fractions of Cu/Zn peaked, promoting their accumulation in the belowground parts of Canna indica. Simultaneously, exogenous root exudates ameliorated the inhibition of chlorophyll synthesis in plants, with the 10 mL·pot-1 dose showing the most significant effect. Plant combination stabilized the sediment environment, reducing fluctuations in dehydrogenase activity. Through rhizosphere effects, it also enhanced microbial species richness and diversity, suppressed dominant bacterial proliferation, increased functional microbe abundance, and improved community stability under stress. This study reveals that root exudates strengthen remediation via a tripartite synergistic mechanism, including activating heavy-metal fractions, improving plant physiology, and optimizing microbial community structure, highlighting its critical significance for rehabilitating antibiotic-heavy metal co-contaminated sediments. |
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