Antibiotic and microplastic co-exposure: Effects on Daphnia magna and implications for ecological risk assessment

The pervasive presence of antibiotics and microplastics in aquatic environments poses a significant ecological concern. These contaminants, known for their environmental persistence and bioaccumulation potential, cause adverse effects on aquatic organisms, such as reduced growth, impaired reproduction, and altered behavior. However, few reviews exist on the ecotoxicological effects of co-exposure to antibiotics and microplastics on aquatic organisms and the associated risk assessment. Utilizing Daphnia magna, a key bioindicator in freshwater ecosystems, this review examines the combined effects of antibiotics and microplastics. Both acute and chronic toxicities manifested as changes in mortality, behavior, and physiological and biochemical processes were summarized. The influence of environmental factors on the interactions between antibiotics and microplastics as well as their effects on the test organism was reviewed. Further, the ecological risks of antibiotics based on D. magna were assessed by the risk quotient methodology, revealing that while individual antibiotics might pose a low to moderate risk, their interaction with microplastics potentially heightens the overall ecological threat. Thus, to advance our understanding, integrating the toxicokinetic-toxicodynamic model with adverse outcome pathways as a refined approach for risk assessment in co-exposure scenarios is necessary. Future research should focus on investigating long-term, multigenerational effects, developing advanced analytical techniques, and incorporating complex environmental interactions into ecological risk assessment approaches. Overall, this review underscored the need for extensive research and comprehensive data collection to guide effective management and mitigation strategies for antibiotic and microplastic pollution in aquatic environments.