A critical review of the adsorption-desorption characteristics of antibiotics on microplastics and their combined toxic effects

The interaction between microplastics (MPs) and pollutants is crucial for assessing the environmental risk of MPs. It is necessary to pay attention to the adsorption/desorption behavior of antibiotics on MPs due to their potential role in antibiotic resistance. When MPs-loaded antibiotics are ingested by organisms, they enter the gastrointestinal tract and undergo desorption, leading to corresponding toxic effects. Existing literature primarily focuses on the adsorption behavior, while there is a lack of systematic generalizations on desorption behavior or the combined toxic effects on organisms. Therefore, this article provides a systematic review of the desorption behavior, mechanisms, and potential effects of MPs-loaded antibiotics in the biological gastrointestinal tract. Desorption behavior suggests that the characteristics of MPs (aging and hydrophobicity) and the components of gastrointestinal fluid (digestive enzyme species and pH) can also have a combined effect on desorption. Moreover, this article also summarizes the combined toxic effects induced by MPs-antibiotics, demonstrating that MPs can either enhance or reduce the toxic effects of antibiotics on plants, microorganisms, aquatic organisms, and animals. Since methodological uniformity and relevance to the natural environment are the main shortcomings of the existing literature, future research should focus on the adsorption and desorption behavior of antibiotics of MPs in the actual water environment of a given region and studying the combined toxic effects of MPs and antibiotics at the gene, protein, and metabolic levels. This review direction is expected to provide valuable references and insights for evaluating the toxic effects of MPs and antibiotics.