Mitigation effects of the microbial fuel cells on heavy metal accumulation in rice (Oryza sativa L.)

The increase in toxic heavy metal pollutants in rice paddies threatens food safety. There is an urgent need for lnow-cost remediation technology for immobilizing these trace metals. In this study, we showed that the application of the soil microbial fuel cell (sMFC) can greatly reduce the accumulation of Cd, Cu, Cr, and Ni in the rice plant tissue. In the sMFC treatment, the accumulation of Cd, Cu, Cr, and Ni in rice grains was 35.1%, 32.8%, 56.9% and 21.3% lower than the control, respectively. The reduction of these elements in the rice grain was due to their limited mobility in the soil porewater of soils employing the sMFC. The restriction in Cd, Cu, Cr, and Ni bioavailability was ascribed to the sMFC ability to immobilize trace metals through both biotic and abiotic means. The results suggest that the sMFC may be used as a promising technique to limit toxic trace metal bioavailability and translocation in the rice plants. [Display omitted] •The sMFC can greatly reduce Cd, Cu, Cr and Ni in the rice plant parts.•The reduction of these elements in the rice grain was due to their limited bioavailability.•Reduction in Cd, Cu, Cr and Ni bioavailability was ascribed to the sMFC ability to immobilize metals through both biotic and abiotic means. The soil microbial fuel cells (sMFC) may be used to limit toxic trace metal bioavailability and translocation in the rice plants.