Routes of Microplastic Exposure and Human Ingestion

With increasing attention to the potential health risks of microplastics, current toxicological studies primarily focus on simplified exposure models (single polymer types, single particle sizes), which are far from reflecting actual microplastic exposure scenarios. A quantitative assessment of the real-world human exposure to complex microplastic mixtures is still lacking. Therefore, this chapter presented a comprehensive exposure assessment for Chinese adults among three age groups of 18–44, 45–59, and 60–69 years, through integrating microplastic concentrations from drinking water, airborne particles, fish and shellfish, plant-derived foods, milk and dairy products, and seasonings. Using a Monte Carlo modeling approach, the average daily intake of microplastics for adults aged 18–44, 45–59, and 60–69 years was estimated to be 13.76, 11.03, and 10.69 particles/kg-bw/day, respectively, which was equivalent to an approximate daily intake of 853, 696, and 630 particles. Drinking water accounted for 82% of total particle intake, followed by inhalation, which accounted for 14%, while other dietary sources collectively contributed 4%. The predominant types of microplastics exposed were polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polyamide (PA). Approximately 66% of particles were smaller than 500 μm, while 20% of particles were within the range of 200–500 μm.