In a research article published on September 22, 2021, in the peer-reviewed journal Environmental Science & Technology Letters, Junjie Zhang from the University School of Medicine, New York, US, reported on the presence of polyethylene terephthalate (PET) and polycarbonate (PC) microplastics in newborn, infant, and adult feces.
The scientists collected feces samples from three newborns (the feces of a newborn is called meconium), six one-year-old infants, and ten adults from New York State. They then extracted the plastic particles and analyzed them with mass spectrometry. They detected both microplastic types in all infant stool and some meconium samples. PC was also present in all adults’ samples and PET in most, “but at concentrations an order of magnitude lower than in infants for PET” microplastics. To find out whether ingested microplastics are degraded in the gut, they also measured the concentrations of terephthalic acid (TPA) and bisphenol A (BPA) since these are monomers used to produce PET and PC polymers, respectively. Although TPA was detected in all feces samples, and BPA in some, the study did not find a correlation between the concentration of PET and PC microplastics and that of their respective monomer.
Based on the feces concentrations and under the assumption that all detected microplastics stem from the diet, the researchers estimated the daily intake of the plastic particles. While the estimated mean daily exposure of adults was 5800 ng/kg body weight per day for PET and 200 for PC, exposure in infants was 83,000 and 660 ng/kg body weight per day for PET and PC, respectively. Thus, the authors concluded microplastics exposure of infants to be higher than that of adults and attributed infant’s higher exposure to the extensive use of products such as toys, teethers, and bottles. However, it was emphasized that larger studies are needed to validate their results.
While Zhang et al. are the first to assess microplastics in the feces of human infants, a previous study detected nine types of microplastics in the stool of adults from seven European countries and Japan (FPF reported). The impacts of microplastic exposure to humans are still poorly understood. To remedy that, five Horizon 2020 projects are now working on the topic with one of the projects, AURORA, focusing on the effects of micro- and nanoplastics on early life health (FPF reported). Studies have already demonstrated that certain concentrations of small plastic particles can have negative impacts in vivo (FPF reported) or in vitro. For instance, in a recent research article, published online on September 15, 2021, in the journal Science of The Total Environment, Wei Cheng from Shanghai Jiao Tong University School of Medicine, Shanghai, China, and co-authors exposed cell-derived liver organoids to polystyrene microplastics and reported these “to cause hepatotoxicity and disrupt lipid metabolism.”
Zhang, J. (2021). “Occurrence of Polyethylene Terephthalate and Polycarbonate Microplastics in Infant and Adult Feces.” Environmental Science & Technology Letters. DOI: 10.1108/BFJ-04-2021-https://doi.org/10.1021/acs.estlett.1c00559
Cheng, W. (2021). “Polystyrene microplastics induce hepatotoxicity and disrupt lipid metabolism in the liver organoids.” Science of The Total Environment. DOI: doi.org/10.1016/j.scitotenv.2021.150328
American Chemical Society (September 22, 2021). “Infants have more microplastics in their feces than adults.” ScienceDaily
Sofia Quaglia (September 22, 2021). “More microplastics in babies’ feces than in adults’ – study.” The Guardian