Aggravation of Cd availability in the plastisphere of paddy soil

Soil plastisphere has attracted many concerns, however, its influence on cadmium (Cd) availability in paddy soil was still unclear. This study carried out batch microcosmic and bagging experiments to explore the influence of microplastic (MPs) on Cd availability in paddy soil under flooding conditions in the view of plastisphere. Results showed that the presence of MPs could act as plastisphere micro-environment. The bacterial community composition changed dramatically around the plastisphere compared with MPs-contaminated bulk soil and control soil. The relative abundance of Symbiobacteraceae, Rhodocyclaceae and Bryobacteraceae was improved in the plastisphere which contributed to the enhanced the reduction of Fe(III) and sulfate in flooding paddy soil. The higher content of Fe(II) and S content contributed to the enrichment of Cd in the plastisphere which aggravated Cd availability in paddy soil under flooding conditions. The partial least squares structure equation modeling results confirmed the presence of MPs in paddy soil could act as plastisphere which could change the bacterial community composition and improve the content Fe and S that was conductive to gather Cd in plastisphere. This study shed lights on the understanding of the role of plastisphere on Cd availability in paddy field ecosystem under flooding conditions.