Interactions of microplastics with organic, inorganic and bio-pollutants and the ecotoxicological effects on terrestrial and aquatic organisms.

As emerging contaminants, microplastics (MPs) have attracted global attention. They are a potential risk to organisms, ecosystems and human health. MPs are characterized by small particle sizes, weak photodegradability, and are good environmental carriers. They can physically adsorb or chemically react with organic, inorganic and bio-pollutants to generate complex binary pollutants or change the environmental behaviors of these pollutants. We systematically reviewed the following aspects of MPs: (i) Adsorption of heavy metals and organic pollutants by MPs and the key environmental factors affecting adsorption behaviors; (ii) Enrichment and release of antibiotic resistance genes (ARGs) on MPs and the effects of MPs on ARG migration in the environment; (iii) Formation of "plastisphere" and interactions between MPs and microorganisms; (iv) Ecotoxicological effects of MPs and their co-exposures with other pollutants. Finally, scientific knowledge gaps and future research areas on MPs are summarized, including standardization of study methodologies, ecological effects and human health risks of MPs and their combination with other pollutants.