Insight into the transformation of phosphorus in soil affected by microplastics: A review

The presence of microplastics (MPs) exerts detrimental effects on soil ecosystems worldwide, subsequently affecting the soil phosphorus (P) cycling. However, the effects of MPs on soil P availability and speciation remain inconsistent, and the underlying factors and mechanisms have not been systematically discussed. Therefore, the impact of MPs on the availability and speciation of P should be clarified for the efficient management of P in the MP-polluted farmland soil. This study provides a systematic review of the effects of MPs on the transformation of P in soil, and special emphasis is given to the influence pathway and mechanisms. In the light of meta-analysis results, the addition of MPs significantly decreased the P availability in soil by 7.28 %-55.94 % (P < 0.05). The responses of soil P species to MPs were mainly driven by MP characteristics, soil properties, and exposure durations. MPs influenced soil P transformation through multiple pathways including P adsorption, alterations in soil physicochemical properties, modifications to microbial communities, and changes in soil phosphatase activities. Further studies should prioritize high-resolution identification of P species and analysis of P-related microbial functional genes to further reveal the evolution of soil P during the MP-mediated process.