Microplastics in soil aggregates: Analytical methods, occurrence patterns, impact analyses and removal approaches

Abstract

Aggregates, as the basic structural soil units, play a crucial role in maintaining soil functions. The pollution of soil aggregates by microplastics (MPs) has thus raised significant concerns. This paper presents a comprehensive review on the analytical methods, occurrence patterns, ecological impacts and biodegradation of MPs sequestered in soil aggregates. Although analytical methods for studying aggregate-associated MPs lack standardization, research indicates that aggregates serve as hotspots for MP pollution. Our review provides evidence that the concentrations used to investigate the impacts of MPs on aggregate turnover and functions do not correspond to environmentally realistic concentrations. Furthermore, microbial-mediated MP degradation is of great advantage and potential in mitigating MP pollution in aggregates. Finally, future perspectives have been proposed, highlighting the significance of revealing the fate and behavior of MPs trapped in aggregates based on innovative analytical methods.