The current status of studies of human exposure assessment of microplastics and their health effects: a rapid systematic review

This rapid systematic review aims to summarize studies of human exposure to microplastics (MPs) and their health effects. For the systematic literature review, we separately searched for review articles and original articles published from 2000 to 2019 in the PubMed, NDSL, KMBASE, and Cochrane databases. A total of 276 review articles and 475 original articles were independently evaluated and eligibility of each article was assessed by two researchers. Finally, 8 review articles and 13 original articles were selected for analysis. There was no standardized methodology for determining human exposure to MPs. Therefore, the size, shape, color, and chemical composition of MPs were considered as factors that affected human exposure to MP. We ascertained that human exposure to MPs occurs through two major routes: inhalation and ingestion. The general population can be exposed to MPs through the food chain, food, and mineral water. Thus, there are multiple scenarios for the exposure process. The only exposure marker in humans is the detection and measurement of MPs in feces. Health effects of human exposure to MPs include respiratory effects from inhalation, digestive effects from ingestion, oxidative stress, and cancer. However, there are few studies of the effects of MP exposure in the general population. Based on a systematic review, we propose a standardized methodology to identify various exposure scenarios to facilitate studies of human exposure to MPs and their health effects.