Microplastics: From Intrinsic Properties to Environmental Fate

The prevalence of microplastics (MPs) in the environment is an escalating global concern, driven by their increasing abundance and potential adverse effects. Their detrimental environmental consequences and risks to public health necessitate urgent action to mitigate their impacts. To better understand MP accumulation within the environment, estimate their impacts, and develop effective mitigation strategies, it is imperative to advance our knowledge of MPs’ environmental fate and how this fate is linked with plastics’ intrinsic properties. We highlight the current research on MPs’ accumulation within different environmental sinks and identify the critical knowledge gaps in understanding the flux of MPs between these sinks. We also discuss how the intrinsic properties of MPs, including polymeric backbone, structure, chemical additives, crystallinity, molecular weight, and hydrophilicity, influence their environmental behavior and degradation pathways. Among these properties, the polymeric backbone and functional groups serve as primary drivers of MP stability when exposed to external physical and chemical factors, thereby influencing the pathway and rate of MP degradation. Other intrinsic properties and environmental conditions mostly impact the rate of MP degradation. As MPs undergo environmental degradation, changes in their intrinsic characteristics can lead to further fragmentation. This process potentially enhances environmental harm due to the resulting particles’ increased surface area, greater environmental mobility, and higher potential for contaminant transport. These factors collectively contribute to the complex dynamics of MPs’ fate and impact on the environment.