Evaluation of micro(nano)plastics and additives in human blood: A pilot study with university students

Micro(nano)plastics (MNPs) are important emerging contaminants that may enter human body through various pathways. Metallic and organic additives in plastics have also attracted attention due to their potential biotoxicity. However, few studies have simultaneously measured MNPs and additives in human samples, which has prohibited a reasonable assessment of their combined exposure levels and association in human bloodstream. To address this knowledge gap, we collected and analyzed blood samples from 36 students in an area university for MNPs and various metallic and organic additives, explored the possible associations between MNPs and additives, and evaluated potential exposure sources. In 83 % of the samples, MNPs were detectable with polyethylene being the most common polymer type. Metals, phthalic acid esters, and synthetic phenolic antioxidants were also widely found in human blood. At least four metallic and one organic additives were detected in the samples containing detectable MNPs. Moreover, the concentration of polyethylene was significantly correlated with those of Pb and 2,6-di-tert-butyl-p-cresol. However, a comparison between the calculated masses of additives loaded on MNPs in blood and the actual measured masses of additives in blood suggested that the additives might not primarily originate from detected MNPs in blood. Correlation analysis based on questionnaire results showed that frequently eating seafood may increase the exposure levels of metals. Maintaining regular exercise can reduce pollutant loads in blood. Overall, the present study demonstrates the co-occurrence of MNPs and certain metals and organic additives in blood and indicates that their complex association requires further investigations.