Interactions of microplastics with heavy metals in the aquatic environment: Mechanisms and mitigation

• The review revealed key gaps in knowledge on HMs binding to MPs. • The review showed that high temperatures and low salinity boost metal adsorption. • Al, Zn, Cu, Ni, Mn, and Cr were frequently detected on MPs across reviewed studies. • The review found a lack of data on MP- metal co-exposure effects on health. • Promising hybrid methods for MPs and metals removal were identified in the review. Microplastics (MPs) and heavy metals (HMs) are significant pollutants in aquatic ecosystems, posing substantial risks to both environmental and human health. Despite growing research interest, the quantitative understanding of MPs-HMs interactions remains limited due to methodological inconsistencies and insufficient cross-study data synthesis. This review presents a data-driven and mechanistic evaluation of these interactions, focusing on sorption and desorption mechanisms and the impact of key physicochemical parameters, including pH, salinity, temperature, and dissolved organic matter. Experimental data are analyzed to reveal trends in adsorption capacity across different polymers, particle sizes, and metal species. The review also synthesizes toxicological effects on aquatic organisms and humans and assesses recent advances in modeling and remediation approaches. Hybrid techniques integrating conventional and emerging technologies show promise for the simultaneous removal of MPs and HMs, though challenges persist for large-scale implementation. By linking quantitative trends with mechanistic insights, this review identifies critical knowledge gaps, outlines directions for future experimental validation, and supports the development of standardized protocols for environmental monitoring, risk assessment, and remediation.