Distribution pattern of legacy and “novel” brominated flame retardants in different particle size fractions of indoor dust in Birmingham, United Kingdom

• PBDEs and NBFRs measured in floor dust (FD) and elevated surface dust (ESD).
• Particle size distribution of PBDEs and NBFRs studied.
• Concentrations of most target BFRs in ESD exceed significantly those in FD.
• Concentrations of more volatile BFRs higher in finer particle size fractions.
• Concentrations of less volatile BFRs do not vary significantly with particle size.

This study investigates the particle size distribution of eight polybrominated diphenyl ethers (PBDEs) and five “novel” brominated flame retardants (NBFRs) in settled house dust. Elevated surface dust (ESD) and floor dust (FD) were collected from 5 homes in Birmingham, UK, yielding a total of 10 samples. Each sample was fractionated into three different particle sizes: 125–250 μm (P1), 63–125 μm (P2) and 25–63 μm (P3). Non-fractionated bulk dust samples (BD) were also analysed. BDE-209 predominated, comprising an average 74.3%, 77.3%, 69.2%, and 62.7% ΣBFRs of BD, P1, P2 and P3 respectively. Σ5NBFRs contributed 24.2%, 21.5%, 29.0% and 35.3% ΣBFRs, while Σ7tri-hepta-BDEs represented 1.5%, 1.2%, 1.7%, and 2.0% ΣBFRs. BEH-TEBP was the predominant NBFR contributing 76.9%, 75.1%, 83.1%, and 83.9% ΣNBFRs in BD, P1, P2 and P3 respectively; followed by DBDPE which contributed 20.1%, 21.9%, 14.1% and 13.9% ΣNBFRs. EH-TBB, BTBPE and PBEB were the least abundant NBFRs. Concentrations of Σ7tri-hepta-BDEs and BEH-TEBP in P3 exceeded significantly (P < 0.05) those in P2, with those in P2 exceeding significantly those in P1. In contrast, no significant differences were found between concentrations of BDE-209, EH-TBB, BTBPE, and DBDPE in different particle size fractions. Concentrations of Σ7tri-hepta-BDEs, BDE-209, and BEH-TEBP in ESD exceeded significantly those in FD (P < 0.05). Normalising BFR concentrations to organic carbon content, did not alter these findings. This suggests that differences in BFR concentrations between different particle size fractions are caused by variations in particle surface area to volume ratio, rather than by variations in organic carbon content.