A low-volume air sampling method for legacy and novel brominated flame retardants in indoor environment using a newly developed sorbent mixture

Abstract

Brominated flame retardants (BFRs) are a series of stable and outstanding flame retardants bringing human exposure risks in indoor environment. However, sampling methods now available for BFRs are solvent-consuming and relatively complicated. This study provides a new option of low-volume air sampling device using cartridges with a sorbent mixture for different types of legacy and novel BFRs. In this study, we found that HC-C18 sorbent is most suitable for polybrominated diphenyl ethers (PBDEs) and novel BFRs (NBFRs) enrichment, and that NH2 for hexabromocyclododecanes (HBCDs). The sorbent mixture was optimized using a complex of HC-C18 and NH2 sorbents with elution recovery of 69.4% ± 7.9–117% ± 10%, pumping-through recovery of 84.5% ± 7.9–127% ± 36%, and breakthrough recovery of 70.8% ± 3.4–118% ± 6% for PBDEs, NBFRs, and HBCDs in indoor air. A sequential elution was also achieved using hexane for PBDEs and NBFRs and ethyl acetate for HBCDs. The method was validated with field sampling at nine student dormitory rooms. For legacy BFRs, all the isomers of HBCDs were detected in the air of nine rooms with the median concentrations of 91, 33, and 25 pg/m3 for (±)α-HBCD, (±)β-HBCD, (±)γ-HBCD, respectively, while PBDEs were hardly detected. In contrast, NBFRs were detected at total concentrations of 15–811 pg/m3. Pentabromotoluene (PBT) was the most frequently detected NBFRs with a median concentration of 4 pg/m3, followed by EHTBB at 56 pg/m3 and HBBZ at 21 pg/m3. For the risk assessment, the total hazard index value for air inhalation of BFRs was estimated at 6.1⎓10−4–0.35, which are consistently lower than 1, indicating no immediate health risk, while their long-term effects remain worth concerns.