Microplastics in house dust from 12 countries and associated human exposure.

Global marine pollution by microplastics (MPs) has received considerable attention in recent years. Nevertheless, little is known about the occurrence of MPs in indoor environments. A novel analytical method was used to quantitatively determine polyethylene terephthalate (PET)- and polycarbonate (PC)- based MPs in 286 indoor dust samples collected from 12 countries. PET-based MPs were detected in all dust samples at concentrations of 38-120,000 µg/g (median: 5900 µg/g), whereas PC-based MPs were measured at <0.11-1700 µg/g (median: 8.8 µg/g). Significant positive correlations were found between the concentrations of terephthalic acid (a PET monomer) and PET as well as between bisphenol A (a PC monomer) and PC. Based on the concentrations of MPs measured in indoor dust, the median daily intake of PET-based MPs calculated for infants was in the range of 4000-150,000 ng/kg-bw/day.