Occupational exposure to commercial decabromodiphenyl ether in workers manufacturing or handling flame-retarded rubber

Commercial decabromodiphenyl ether (DecaBDE) is commonly used as a flame retardant in different electrical and textile applications. It is also used in the production of flame-retarded rubber compound. DecaBDE is the major technical polybrominated diphenyl ether (PBDE) in use today and consists mainly of decabromodiphenyl ether(BDE209). PBDEs, including BDE-209, are well-known environmental pollutants, ubiquitous both in aquatic and terrestrial environments. The aim of the present study was to assess the exposure to PBDEs in workers manufacturing or handling rubber which was flame retarded with DecaBDE. A referent group, abattoir workers (slaughterhouse workers), with no occupational exposure to PBDEs, was also investigated. Moreover, the methodology for analysis of PBDEs in serum was refined, with special emphasis on congeners with a high number of bromine substituents, i.e., octa- to decaBDEs. The highest BDE-209 concentration observed among the rubber workers was 280 pmol/g lipid weight (I.w.) (270 ng/g I.w.). The median concentration of BDE-209 among rubber workers was 37 pmol/g l.w. (35 ng/g I.w.). Among referents, the median was 2.5 (range 0.92-9.7) pmol/g I.w. (median 2.4 ng/g I.w.). In rubber workers the BDE-209 concentrations were up to 32% (median 4%) of the 2,2',4,4',5,5'-chlorobiphenyl (CB-153) concentrations, on a molar basis, whereas the referents had BDE209 concentrations which were similar to that of 2,2',4,4'bromodiphenyl ether (BDE-47), below 1.4% (median 0.3%) of the CB-153 concentration. Concentrations of all nonabromodiphenyl ethers (nonaBDEs) and several octabrmodiphenyl ethers (octaBDEs) congeners, including BDE-203, were also elevated among the rubber workers, with 2.5-to 11-fold higher median concentrations, compared to the referents. The results confirm a significant uptake of BDE-209 in the workers exposed to DecaBDE and indicate a potential for in vivo formation of lower BDEs in these persons.