Role of Aquatic Dissolved Organic Matter in the Entrainment of Microplastics under Freezing Conditions

Microplastics (MPs) can be trapped in sea ice, acting as a temporary storage and transportation medium. The aim of this study is to investigate the interaction between aquatic organic matter and MPs and the roles of aquatic organic matter in the entrainment behaviors of MPs in ice formation processes. Our study investigated the effects of aquatic dissolved organic matter on the properties of MPs through a 28 day interaction experiment conducted under both UV and dark conditions. The implications of the alteration in MP properties on their entrapment in ice were also explored in an ice formation experiment. The presence of aquatic organic matter on the MPs after the interactions was confirmed, but the interaction with aquatic organic matter had different impacts on the two types of MPs. Furthermore, the entrapment of MPs in ice was improved after their interaction with aquatic organic matter due to surface damage caused by physical abrasion and UV radiation. These findings underscore the critical role that the inherent properties of MPs play in determining their environmental behavior. These properties can significantly impact their interactions with other natural components in the environment, thereby influencing their behavior in a cold environment.