The environmental and health challenges posed by petroleum-based biodegradable plastics, such as polybutylene succinate (PBS) and polybutyleneadipate-co-terephthalate (PBAT), are a significant concern because they are increasingly present in the environment and contribute a substantial proportion of microplastics (MPs) or nanoplastics (NPs). In this study, ultraviolet (UV)-aged PBS-NPs and PBAT-NPs are found to have a higher propensity to accumulate within the body of