Occurrence of polybrominated biphenyls, polybrominated dibenzo-p-dioxins, and polybrominated dibenzofurans as impurities in commercial polybrominated diphenyl ether mixtures

The objective of this study was to determine the concentrations and compositions of polybrominated biphenyls (PBBs), polybrominated dibenzo-p-dioxins (PBDDs), and polybrominated dibenzofurans (PBDFs) as contaminants in the commercial polybrominated diphenyl ether (PBDE) mixtures DE-71, DE-79, and DE-83 and to ascertain the lot-to-lot variations in the proportions of these contaminants. Commercial PBDE mixtures tested in the present study contained both PBBs and PBDFs, as impurities, at concentrations in the range of several tens to several thousands of nanograms per gram. Concentrations of total PBDFs were greater than those of total PBBs in DE-79 and DE-83 mixtures. PBDDs were not detected at levels above the limit of detection. Profiles of PBB and PBDF congeners varied with the degree of bromination of the commercial PBDE mixtures (i.e., more highly brominated mixtures of PBDEs contained heavily brominated homologues of PBBs and PBDFs). On the basis of the production/ usage of commercial PBDE mixtures in 2001, potential global annual emissions of PBBs and PBDFs were calculated to be 40 and 2300 kg, respectively. Results of our study suggestthat PBDFs can also be formed during the production of commercial PBDE mixtures, in addition to their formation during pyrolysis of brominated flame retardants.