Global review of macrolide antibiotics in the aquatic environment: Sources, occurrence, fate, ecotoxicity, and risk assessment

The extensive use of macrolide antibiotics (MCLs) has led to their frequent detection in aquatic environments, affecting water quality and ecological health. In this study, the sources, global distribution, environmental fate, ecotoxicity and global risk assessment of MCLs were analyzed based on recently published literature. The results revealed that there are eight main sources of MCLs in the water environment. These pollution sources resulted in MCL detection at average or median concentrations of up to 3847 ng/L, and the most polluted water bodies were the receiving waters of wastewater treatment plants (WWTPs) and densely inhabited areas. Considering the environmental fate, adsorption, indirect photodegradation, and bioremoval may be the main attenuation mechanisms in natural water environments. N-demethylation, O-demethylation, sugar and side chain loss from MCL molecules were the main pathways of MCLs photodegradation. Demethylation, phosphorylation, N -oxidation, lactone ring hydrolysis, and sugar loss were the main biodegradation pathways. The median effective concentration values of MCLs for microalgae, crustaceans, fish, and invertebrates were 0.21, 39.30, 106.42, and 28.00 mg/L, respectively. MCLs induced the generation of reactive oxygen species, that caused oxidative stress to biomolecules, and affected gene expression related to photosynthesis, energy metabolism, DNA replication, and repair. Moreover, over 50% of the reported water bodies represented a medium to high risk to microalgae. Further studies on the development of tertiary treatment technologies for antibiotic removal in WWTPs, the combined ecotoxicity of antibiotic mixtures at environmental concentration levels, and the development of ac-curate ecological risk assessment models should be encouraged.

Automated summary

The extensive use of macrolide antibiotics has led to their frequent detection in aquatic environments, affecting water quality and ecological health. This study analyzes the sources, distribution, fate, ecotoxicity, and global risk assessment of macrolide antibiotics based on recent literature. The results show that there are eight main sources of macrolide antibiotics in the water environment, and the most polluted water bodies are wastewater treatment plants and densely inhabited areas. Adsorption, photodegradation, and bioremoval are the main attenuation mechanisms in natural water environments. Macrolide antibiotics have ecotoxic effects on microalgae, crustaceans, fish, and invertebrates, causing oxidative stress and affecting gene expression. Over 50% of reported water bodies represent medium to high risk to microalgae. Further research on antibiotic removal technologies, combined ecotoxicity of antibiotic mixtures, and accurate ecological risk assessment models is encouraged.