Polybrominated biphenyl exposure and thyroid function tests in electronic waste dismantling and general population of Chinese adults

This study aimed to determine the concentration of 35 PBB(polybrominated biphenyls)congeners in the human serum of residents from an electronic waste(e-waste)dismantling area compared to a control area in China.Additionally,four thyroid hormones,namely FT3,FT4,TSH,and TRH,were also analyzed.The findings revealed that the total PBB concentrations(sum of the 35 PBB congeners)ranged from 47.1 to 1360 ng/g lipid in the e-waste area and 105–1980 ng/g lipid in the control area.BB-1 and BB-10 were the dominant congeners in both study areas,followed by BB-209.Compared to the e-waste dismantling area,the control area samples had a significantly higher concentration of less-brominated(Br1–3)PBBs,including the concentrations of less-brominated congeners such as BB-1,BB-4,BB-9,and BB-10,which were significantly higher than those in the e-waste dismantling area.Conversely,more-brominated hexabromobiphenyl congeners BB-153,BB-154 and BB-155 were found in samples from the e-waste dismantling area at significantly higher concentrations than in the control area.E-waste dismantling areas have released historically produced commercial PBB products,but equally not negligible is the exposure of the general population to newly produced PBB congeners.PBB concentrations in the e-waste dismantling area samples decreased with increasing age,while they increased with increasing age in the control area samples.Furthermore,stepwise multiple regression analysis showed a significant association between BB-103 concentrations and thyroid hormone levels.In addition,BB-103 has the potential to interfere with the binding of T3 and thyroid hormone receptors(TR).Given these findings,the research on human exposure of PBB and the relationships between the PBB and thyroid hormones should be studied further.