Thaw-window mismatch in soil organic-pollutant fate under freeze-thaw cycles: redistribution, boundary-export risk,...

Climate warming may intensify freeze-thaw disturbance in cold-region and seasonally frozen soils, which have long been regarded as relatively stable reservoirs for organic pollutants but can undergo episodic remobilization during thaw. However, freeze-thaw effects are still often evaluated through concentration changes or inventory shifts, whereas the short thaw window during which transport activation may precede attenuation recovery remains insufficiently resolved. This Review develops a thaw-window mismatch framework to examine the non-steady-state fate of soil organic pollutants under freeze-thaw cycles. We synthesize evidence that pore-network reconnection, unfrozen-water redistribution, dissolved organic matter (DOM) and colloid mobilization, redox fluctuation, and delayed microbial recovery can jointly reconstruct environmental boundary conditions controlling pollutant release, migration, retention, transformation, and potential export. Within this framework, we organize thaw-induced fate into a sequence of preconditioning, pulse release, redistribution, delayed transformation, and retention-export bifurcation, from which four representative risk phenotypes are identified across hydrophobic pollutants, persistent mobile compounds, ice-interface-reactive compounds, and multiphase source-zone contaminants. This synthesis supports event-scale diagnosis based on connectivity, carrier mobilization, mobile pollutant forms, attenuation recovery, and boundary-flux signals, and provides a basis for process-matched control strategies across pre-thaw stabilization, first-flush interception, and post-thaw functional reinforcement.