DOE OSTI2018
Highlights: • Indoor dust from office/public microenvironments/cars were separated into 6 size fractions. • FR distribution was dependent on Kow/dust surface area/TOC/FR migration pathway. • OPFR bioaccessibility was 1.8–82%, bioaccessible PBDEs/NBFRs/DPs were < detection limit. • Human exposure to FR was dependent on dust particle size and bioaccessibility. The effect of dust particle size on the distribution and bioaccessibility of flame retardants (FRs) in indoor dust remains unclear. In this study, we analyzed 20 FRs (including 6 organophosphate flame retardants (OPFRs), 8 polybrominated diphenyl ethers (PBDEs), 4 novel brominated flame retardants (NBFRs), and 2 dechlorane plus (DPs)) in composite dust samples from offices, public microenvironments (PME), and cars in Nanjing, China. Each composite sample (one per microenvironment) was separated into 6 size fractions (F1–F6: 200–2000 µm, 150–200 µm, 100–150 µm, 63–100 µm, 43–63 µm, and 9). Bioaccessibility of FRs was measured by the physiologically-based extraction test, with OPFR bioaccessibility being 1.8–82% while bioaccessible PBDEs, NBFRs, and DPs were under detection limits due to their high hydrophobicity. The OPFR bioaccessibility in 200–2000 µm fraction was significantly higher than that of <43 µm fraction, but with no difference among the other four fractions. Risk assessment was performed for the most abundant OPFR-tris(2-chloroethyl) phosphate. The average daily dose (ADD) values were the highest for the <43 µm fraction for all three types of dust using total concentrations, but no consistent trend was found among the three types of dust if based on bioaccessible concentrations. Our results indicated that dust size impacted human exposure estimation of FRs due to their variability in distribution and bioaccessibility among different fractions. For future risk assessment, size selection for dust sampling should be standardized and bioaccessibility of FRs should not be overlooked.
54 ENVIRONMENTAL SCIENCES↗