Microplastics and complex environmental contaminants: Interactions with heatwave, pesticides, pharmaceuticals, and...

Microplastics (MPs) are widespread environmental contaminants found across both aquatic and terrestrial ecosystems. While many studies have explored interactions between MPs and individual environmental stressors such as pesticides, pharmaceuticals, pathogens, or temperature changes, these interactions are rarely examined together. In natural environments, MPs are exposed to multiple stressors simultaneously, which may interact in complex ways and affect their environmental behavior and biological effects. This study systematically reviews and bibliometrically analyzes peer-reviewed literature on MP interactions with major environmental stressors, focusing on heatwaves, pesticides, pharmaceuticals, and pathogens. Bibliometric and keyword analyses were performed to identify research trends and key themes. Using Web of Science and Scopus, 4412 records were initially identified, with 2120 studies selected after screening per PRISMA (Preferred Reporting Items for Systematic Reviews & Meta-Analysis) guidelines. The key analyses revealed four main research clusters: toxic effects on organisms, microbial and plastisphere dynamics, physicochemical adsorption processes, and mitigation strategies. Most current research focuses on experiments with one or two stressors, leaving multi-stressor interactions poorly understood. This gap may hinder a full understanding of the ecological risks posed by MPs. Future studies should emphasize multi-stressor experiments conducted under realistic environmental conditions to better reflect natural systems.