Analysis of adipose tissue and serum from PBB (polybrominated biphenyl)-exposed workers

In the course of clinical examinations of individuals exposed to PBB (polybrominated biphenyls) in Michigan, employees of the chemical company which manufactured PBB also were examined. Analysis of serum and adipose tissue from these workers revealed quantitative and qualitative differences, compared with farm residents exposed to PBB. Serum and fat concentrations of PBB were higher among chemical workers, and the concentrations of PBB homologs were also higher, attributable to different intensity, route (skin, inhalation, direct ingestion vs. ingestion of animal foodstuffs), and composition (unchanged vs. animal-mediated material) of exposure in chemical workers vs. farmers. The unusual nature of occupational exposure was further evident in measurement of serum and fat DDE and identification of serum tetrabromobenzene (TBB). DDE concentrations were higher among employees than among farmers, consistent with the workers' earlier occupational exposure to DDT, which had been produced by the company. Serum TBB was not explicable by direct exposure to the chemical, but has been ascribed to exposure to hexabromobenzene, which was shown to give tetrabromobenzene as a metabolite in the rat.