Effect of microplastics on nasal and gut microbiota of high-exposure population: Protocol for an observational cross-sectional study.

Microplastics have the characteristics of small size, high specific area, strong ability to adsorb pollutants, and difficult to degrade. They have become a major global environmental problem that humans urgently need to address. A balanced microecosystem is essential to human health. Animal studies have shown that long-term exposure to microplastics can change the characteristics of the microbiota in organisms, leading to respiratory, digestive, immune, and other system diseases. However, the current research on microplastics is still dominated by animal experiments, and the impact of microplastics on human health is still in its infancy, so relevant research is urgently needed. Twenty participants with high exposure to microplastics will come from a plastic factory in Chengdu, China. We will perform 16S rDNA sequencing on participants' nasal secretions, and stool samples. Additionally, we will perform 8700 LDIR laser infrared imaging of environmental soil and air filter membrane samples. For comparison, we will also collect samples from 20 volunteers from an area with good environmental quality in Chengdu. To find out the potential predictors and to access the difference between the groups, statistical analysis will be performed in the end. The study will be the first observational cross-sectional study focusing on the effects of microplastics on nasal and gut microbiota of high-exposure population. The study is expected to provide reliable evidence to fill the gaps in the impact of microplastics on human health.