| Hydroxylated Metabolites of Polybrominated Diphenyl Ethers in Human Blood Samples from the United States Xinghua Qiu,1 Robert M. Bigsby,2 and Ronald A. Hites1 1School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana, USA; 2Department of Obstetrics and Gynecology, School of Medicine, Indiana University, Indianapolis, Indiana, USA Abstract
Background: A previous study from our laboratory showed that polybrominated diphenyl ethers (PBDEs) were metabolized to hydroxylated PBDEs (HO-PBDEs) in mice and that para-HO-PBDEs were the most abundant and, potentially, the most toxic metabolites. Objective: The goal of this study was to determine the concentrations of HO-PBDEs in blood from pregnant women, who had not been intentionally or occupationally exposed to these flame retardants, and from their newborn babies. Methods: Twenty human blood samples were obtained from a hospital in Indianapolis, Indiana, and analyzed for both PBDEs and HO-PBDEs using electron-capture negative-ionization gas chromatographic mass spectrometry. Results: The metabolite pattern of HO-PBDEs in human blood was quite different from that found in mice ; 5-HO-BDE-47 and 6-HO-BDE-47 were the most abundant metabolites of BDE‑47, and 5´-HO-BDE-99 and 6´-HO-BDE-99 were the most abundant metabolites of BDE‑99. The relative concentrations between precursor and corresponding metabolites indicated that BDE-99 was more likely to be metabolized than BDE-47 and BDE-100. In addition, three bromophenols were also detected as products of the cleavage of the diphenyl ether bond. The ratio of total hydroxylated metabolites relative to their PBDE precursors ranged from 0.10 to 2.8, indicating that hydroxylated metabolites of PBDEs were accumulated in human blood. Conclusions: The quite different PBDE metabolite pattern observed in humans versus mice indicates that different enzymes might be involved in the metabolic process. Although the levels of HO-PBDE metabolites found in human blood were low, these metabolites seemed to be accumulating. Key words: bromophenols, flame retardants, HO-PBDEs, human blood, metabolites, PBDEs, polybrominated diphenyl ethers. Environ Health Perspect 117:93–98 (2009) . doi:10.1289/ehp.11660 available via http://dx.doi.org/ [Online 1 August 2008]
Address correspondence to R.A. Hites, School of Public and Environmental Affairs, Indiana University, 1315 E. 10th St., Bloomington, IN 47405 USA. Telephone: (812) 855–0193. Fax: (812) 855–1076. E-mail: HitesR@indiana.edu We thank G. Marsh for providing some of the hydroxylated-PBDE standards used in this research. Supplemental Material is available online at http://www.ehponline.org/members/2008/11660/suppl.pdf The authors declare they have no competing financial interests. Received 5 May 2008 ; accepted 1 August 2008.
The full version of this article is available for free in HTML or PDF formats. | 
