A review on enriched microplastics in environment: From the perspective of their aging impact and associate risk

Microplastics (MPs), as a kind of emerging pollutants, have arouse widespread concern with significant impact on ecosystems. Great attempts have been made to remove MPs from natural environments, yet they were still commonly detected with increasing concentration in various environmental media. The ultimate effectiveness of current remediation measures for MP pollution remained largely unexplored. Furthermore, with irreversibility and non-biodegradation, these MPs enriched in environments, exposed to various abiotic and biotic stress for a long-term. Natural aging processes change physicochemical properties and then environmental fate of MPs, inducing potential harm to ecosystems and human health. However, our understanding of aging behavior of MPs remains to be actually interpreted. This review summarized the latest progress in alleviating MP pollution and assessed their usability, especially for the controversial application of biodegradable plastics. The typical abiotic and biotic aging processes of MPs were also discussed. Giving that abiotic processes such as photo-aging are usually considered as prior to biodegradation, we reasonably assume MPs would undergo a prolonged aging process, but not a thorough degradation to a great extent due to their fairly slow degradation rate. This process might aggravate potential risk, especially aged MPs providing more ideal interfaces for the colonization of viral microbes deserves more attention in the future. This article conducts a systematical analysis and summary of long-term environmental behavior of MPs. Future research is encouraged to comprehensively strengthen the removal of MPs in ecosystems through source control and more targeted process treatment. • Current remediation strategies for microplastic (MP) pollution are discussed. • Biodegradable plastics might not be a silver bullet solution to MP pollution. • MPs undergo a prolonged retention, but not a thorough degradation in natural environments. • Aging processes of MPs are affected by abiotic and biotic environmental factors. • MP aging impacts play a vital role in potential risk to ecosystems.