Risk assessment of microplastic particles

Microplastic is a complex contaminant causing great concern in society. This Review examines the properties of microplastic particles compared with natural particles in the environment and discusses methods of assessing the risks to humans and the environment. Microplastic particles are ubiquitous in the environment, from the air we breathe to the food we eat. The key question with respect to these particles is to what extent they cause risks for the environment and human health. There is no risk assessment framework that takes into account the multidimensionality of microplastic particles against the background of numerous natural particles, which together encompass an infinite combination of sizes, shapes, densities and chemical signatures. We review the current tenets in defining microplastic characteristics and effects, emphasizing advances in the analysis of the diversity of microplastic particles. We summarize the unique characteristics of microplastic compared with those of other environmental particles, the main mechanisms of microplastic particle effects and the relevant dose metrics for these effects. To characterize risks consistently, we propose how exposure and effect thresholds can be aligned and quantified using probability density functions describing microplastic particle diversity.

Automated summary

This Review examines the properties of microplastic particles and discusses methods of assessing the risks they pose to humans and the environment. Microplastic particles are widespread in the environment and can be found in the air we breathe and the food we eat. The lack of a risk assessment framework that considers the multidimensionality of microplastic particles compared to natural particles is a key challenge. This article reviews current understanding of microplastic characteristics and effects and proposes a method for quantifying exposure and effect thresholds using probability density functions.