Alternate and New Brominated Flame Retardants Detected in U.S. House Dust

TLDR

Due to voluntary withdrawals and bans on PBDE mixtures, alternate brominated flame retardants are increasingly introduced into commercial products. The study aimed to assess whether these alternate BFRs are present in indoor environments by analyzing dust from 19 Boston homes collected in 2006. Using GC/ECNI‑MS with pure and commercial standards, the authors quantified hexabromocyclododecane, bis(2,4,6‑tribromophenoxy)ethane, decabromodiphenyl ethane, and the Firemaster 550 components 2‑ethylhexyl 2,3,4,5‑tetrabromobenzoate and (2‑ethylhexyl)tetrabromophthalate. Dust samples contained log‑normally distributed levels of these five BFRs, with HBCD ranging from <4.5 to 130,200 ng g⁻¹ (median 230 ng g⁻¹), BTBPE 1.6–789 ng g⁻¹ (median 30 ng g⁻¹), DBDPE <10–11,070 ng g⁻¹ (median 201 ng g⁻¹), TBB <6.6–15,030 ng g⁻¹ (median 133 ng g⁻¹), and TBPH 1.5–10,630 ng g⁻¹ (median 142 ng g⁻¹), with TBB/TBPH ratios ranging 0.05–50 (average 4.4) and higher HBCD, TBB, TBPH in living areas versus bedrooms, underscoring widespread indoor exposure to diverse BFR mixtures.

Abstract

Due to the voluntary withdrawals and/or bans on the use of two polybrominated diphenyl ether (PBDE) commercial mixtures, an increasing number of alternate flame retardant chemicals are being introduced in commercial applications. To determine if these alternate BFRs are present in indoor environments, we analyzed dust samples collected from 19 homes in the greater Boston, MA area during 2006. Using pure and commercial standards we quantified the following brominated flame retardant chemicals using GC/ECNI-MS methods: hexabromocyclododecane (sigma HBCD), bis(2,4,6,-tribromphenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and the brominated components found in Firemaster 550 (FM 550): 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB) and (2-ethylhexyl)tetrabromophthalate (TBPH), the latter compound being a brominated analogue of di(2-ethylhexyl)phthalate (DEHP). The concentrations of all compounds were log-normally distributed and the largest range in concentrations was observed for HBCD (sum of all isomers), with concentrations ranging from <4.5 ng/g to a maximum of 130,200 ng/g with a median value of 230 ng/g. BTBPE ranged from 1.6 to 789 ng/g with a median value of 30 ng/g and DBDPE ranged from <10.0 to 11,070 ng/g with a median value of 201 ng/g. Of the FM 550 components, TBB ranged from <6.6 to 15,030 ng/g with a median value of 133 ng/g; whereas TBPH ranged from 1.5 to 10,630 ng/g with a median value of 142 ng/g. Furthermore, the ratio of TBB/TBPH present in the dust samples ranged from 0.05 to 50 (average 4.4), varying considerably from the ratio observed in the FM 550 commercial mixture (4:1 by mass), suggesting different sources with different chemical compositions, and/or differential fate and transport within the home. Analysis of paired dust samples collected from different rooms in the same home suggests HBCD, TBB, and TBPH are higher in dust from the main living area compared to dust collected in bedrooms; however, BTBPE and DBDPE levels were comparable between rooms. This study highlights the fact that numerous types of brominated flame retardants are present in indoor environments, raising questions about exposure to mixtures of these contaminants.