Occurrence and human exposure assessment of organophosphate flame retardants in indoor dust from various microenvironments of the Rhine/Main region, Germany.

We analyzed organophosphate flame retardants (OPFRs) in 74 indoor dust samples collected from seven microenvironments (building material markets, private cars, daycare centers, private homes, floor/carpet stores, offices, and schools) in the Rhine/Main region of Germany. Ten of 11 target OPFRs were ubiquitously detected, some with more than 97% detection frequency, including tris(1,3-dichloroisopropyl)phosphate (TCIPP), tris(2-butoxyethyl)phosphate (TBOEP), triphenyl phosphate (TPHP), and tris(isobutyl) phosphate (TIBP). Total concentrations (∑OPFRs) ranged from 5.9 to 4800 μg/g, with TBOEP and TCIPP being the most abundant congeners. The ∑OPFRs in schools, private cars, offices, and daycare centers were significantly (P<.05) higher than in private homes. The ∑OPFRs for building material markets (19 μg/g) and floor/carpet stores (20 μg/g) showed no significant difference to the other microenvironments, likely because of forced ventilation. The profiles of OPFRs in dust samples from offices and private homes were highly similar, while profiles from the other five microenvironments were substantially different. Comparison of our results with previous studies indicates a significant global variation in OPFR concentrations and their profiles, reflecting distinct fire safety regulations in different countries and/or different sampling strategies. Dust ingestion constitutes the major exposure pathway to OPFRs for toddlers, while air inhalation is the major pathway for adults.