Brominated flame retardants in dust from UK cars – Within-vehicle spatial variability, evidence for degradation and exposure implications

Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and tetrabromobiphenol-A (TBBP-A) were measured in a preliminary study of dust from passenger cabins and trunks of 14 UK cars. Concentrations in cabin dust of HBCDs, TBBP-A, and BDEs 47, 85, 99, 100, 153, 154, 183, 196, 197, 202, 203, 206, 207, 208, and 209 exceeded significantly (p < 0.05) those in trunk dust. Sampling cabin dust thus appears to provide a more accurate indicator of human exposure via car dust ingestion than trunk dust. Elevated cabin concentrations are consistent with greater in-cabin use of BFRs. In five cars, while no significant differences (p > 0.05) in concentrations of HBCDs and most PBDEs were detected in dust sampled from four different seating areas; concentrations of TBBP-A and of PBDEs 154, 206, 207, 208, and 209 were significantly higher (p < 0.05) in dust sampled in the front seats. Possible photodebromination of BDE-209 was indicated by significantly higher (p < 0.05) concentrations of BDE-202 in cabin dust. In-vehicle exposure via dust ingestion to PBDEs, HBCDs and TBBP-A exceeded that via inhalation. Comparison with overall exposure via diet, dust ingestion, and inhalation shows while in-vehicle exposure is a minor contributor to overall exposure to BDE-99, ΣHBCDs, and TBBP-A, it is a significant pathway for BDE-209.

Research highlights
► Evidence is provided that cars are a source of exposure to BFRs for their occupants.
► Sampling cabin dust rather than trunk dust is recommended.
► Concentrations of some BFRs are higher in front than back seats.
► Cabin dust shows greater evidence of BFR degradation than trunk dust.