Hexabromocyclododecane (HBCD) Stereoisomers in US Food from Dallas, Texas

BACKGROUND: Hexabromocyclododecane (HBCD) is a brominated flame retardant used in polystyrene foams in thermal insulation and electrical equipment. The HBCD commercial mixture consists mainly of alpha, beta, and gamma stereoisomers. Health concerns of HBCD exposure include alterations in immune and reproductive systems, neurotoxic effects, and endocrine disruption. Stereoisomer-specific levels of HBCD have not been measured previously in U.S. food. OBJECTIVES: We measured HBCD stereoisomer levels in U.S. foods from Dallas, Texas, supermarkets. METHODS: Convenience samples of commonly consumed foods were purchased from supermarkets in Dallas in 2009-2010. Food samples included a wide variety of lipid-rich foods: fish, peanut butter, poultry, pork, and beef. Thirty-six individual food samples were collected in 2010 and analyzed for alpha-, beta-, and gamma-HBCD stereoisomers using liquid chromatography tandem mass spectrometry (LC-MS/MS). Ten pooled food samples previously collected in 2009 for a study of total HBCD levels using gas chromatography mass spectrometry (GC-MS), were reanalyzed for alpha-, beta-, and gamma-HBCD stereoisomers using LC-MS/MS. RESULTS: Of the 36 measured individual foods, 15 (42%) had detectable levels of HBCD. Median (ranges) of alpha- and gamma-HBCD concentrations were 0.003 (< 0.005-1.307) and 0.005 (< 0.010-0.143) ng/g wet weight (ww), respectively; beta-HBCD was present in three samples with a median (range) of 0.003 (< 0.005-0.019) ng/g ww. Median levels (range) for alpha-, beta-, and gamma-HBCD, in pooled samples were 0.077 (0.010-0.310), 0.008 (< 0.002-0.070), and 0.024 (0.012-0.170) ng/g ww, respectively. CONCLUSIONS: alpha-HBCD was detected most frequently and at highest concentrations, followed by gamma-, and then beta-HBCD, in food samples from Dallas, Texas. Food may be a substantial contributor to the elevated a-HBCD levels observed in humans. These data suggest that larger and more representative sampling should be conducted.