Interactions of microplastics and heavy metals in soil environment: Bibliometric analysis

The interaction between microplastics (MPs) and heavy metals (HMs) coexisting in soil leads to ecosystem problems and loss of soil function, current research focuses on the ecological risks of specific pollutants and qualitative descriptions of mechanisms, but there is a lack of quantitative analysis and macro-level development characteristic analysis of relevant literature. Hence, based on bibliometric methods, the relevant literature data was processed using the analysis tools, and classified into themes using Latent Dirichlet Allocation (LDA) analysis model. The results show that global research institutions form several regional sub-clusters. Cooperation is frequent inside each cluster, while inter-cluster connections are relatively weak. Moreover, research hotspots are concentrated on adsorption mechanisms, microbial community responses, and ecological risks of combined contamination, and nano-MPs particles and activated carbon remediation technology have become emerging research hotspots. Research trend also evolves from single pollutant effect to multi-factor synergistic risk mechanism. The research topics were obtained through the LDA model, reflecting the need to combine metagenomics and model prediction in future to systematically study the mechanisms of MPs affecting microbe-mediated HMs transformation, while developing eco-friendly materials and control technologies. The results provide powerful references for in-depth investigation of combined contamination remediation of MPs and HMs in soil.