Internal and external microplastic exposure in young adults: A pilot study involving 26 college students in Changsha, China.

OBJECTIVE

This study aimed to systematically assess the total environmental exposure to microplastics and determine the internal exposure levels in the human body.

METHODS

A total of 26 young college students were recruited. Exposure scenario estimation methods were used to establish evaluation models. The dietary and water intake behaviors of the participants were documented with questionnaires. The food and water consumed by the participants were sampled using weight and duplicate meal methods. Furthermore, air samples from the activity regions of the participants were collected. Fasting serum, 24-h urine, and fecal samples were also collected. Pyrolysis gas chromatography/mass spectrometry (Py-GCMS) helped identify the types and determine mass concentrations of microplastics across all samples, and the internal and external exposure levels of microplastics among the population were further evaluated.

RESULTS

Microplastics were frequently observed in food samples, with mass concentrations ranging from 2.50 to 91.30 μg/g. Water samples also contained microplastics, with concentrations ranging from 0.02 to 18.41 μg/g. Indoor and outdoor air contained PS, PE, PP, PVC, and PET. The exposure levels of young college students in Changsha to microplastics through dietary intake, water intake, and inhalation were quantified at 346.65 μg/kg bw/d, 41.17 μg/kg bw/d, and 59.57 μg/kg bw/d, respectively. Cumulatively, the total exposure to microplastics from these three sources was 460.20 μg/kg bw/d. Median microplastic levels in serum and feces samples were 20.81 μg/g and 97.36 μg/g, respectively. Additionally, urine samples indicated the presence of seven types of microplastics (PS, PE, PP, PVC, PET, PA66, and PMMA), with a median exposure level of 5.06 μg/g.

CONCLUSION

Among young college students in Changsha, the primary microplastic exposure source was dietary intake, followed by air and drinking water. The internal exposure level in serum was higher than that in urine.