The aging behaviors and release of microplastics: A review

Microplastics (MPs) have attracted a significant concern due to persistence and their adverse effects on organisms. In this review, we summarize the recent literature regarding the natural and artificial aging process of MPs, also discuss the associated aging characteristics and mechanisms of MPs. The aged MPs showed different morphological and chemical properties from the pristine MPs. Furthermore, to evaluate associated aging effects, the corresponding release of aging process of MPs were systematically revealed, including the additives and intermediates. Different types of organic pollutants and heavy metals additives are listed. In addition, the release of MPs is affected by environmental factors (i.e., Illumination, salinity, temperature and pH). Aged MPs are more easily absorbed by organisms and have different toxic effects from the pristine MPs. The potential risks of aging MPs and the release of MPs during aging are discussed in detail. Based on the current deficiency of published literatures, the prospects are proposed. Therefore, this review provides a direction for further study on the behaviors and the toxic effects of MPs in the environment.