Research Progress on the Effects of Combined Microplastics and Cadmium Pollution on Plants

The toxic effects of soil heavy metals and microplastics on plants have been extensively documented, with some researchers having conducted studies exploring the combination of these two factors. Preliminary findings indicate that their combined action can “reduce biomass, exacerbate oxidative stress, and inhibit photosynthesis,” and the potential mechanisms of this combined toxicity are currently being explored. However, these combined effects remain unclear, with conflicting conclusions across studies. Research subjects are relatively fragmented, and systematic summaries are lacking. This paper systematically reviews current research findings on the combined toxic effects of microplastics and Cd on plants, specifically focusing on the following factors: (1) the mechanisms and influencing factors of Cd adsorption by microplastics: electrostatic adsorption is the primary mechanism, and soil environmental factors are significant influencers; (2) microplastics’ altering of the available Cd content in soil: soil environmental conditions can be modified to increase or decrease available Cd concentrations; (3) The “synergistic or antagonistic” toxic effects of microplastics and Cd on plants. Future research directions warranting in-depth investigation are also identified in this study.