Effects Of Persistent Organic Halogen Compounds On Human Exposure In Production Source Region

Persistent halogenated organic compounds had widely caused environmental pollution around the world. Polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dechlorane plus (DP), pentabromobenzene (PBBz), and pentabromotoluene (PBT) are several main organic halogenated compounds. As their persistence in environmental media and their toxicity to ecology, PCBs and OCPs were banned in the whole or part of the world. PBDEs became the most widely used halogenated flame retardants due to its flarnmability. However, due to the potential toxicity and persistence of their components, the production of the pentaBDE and octaBDE products is now banned worldwide and the use of the decaBDE commercial product has also been banned in the EU and in some states in the USA. Recently DP has been produced and used in some countries as a replacement of Mirex and BDE-209, but studies about its toxicity is quite few. Research about the production and toxicity of PBBz and PBT is scarce. Recently, the impacts of these halogenated compounds on human beings have caused extensive concern in the world.Concentrations of PCBs. OCPs、PBDEs、DP、PBBz and PBT in air samples from Weifang were 1.7 pg/m3、330pg/m3、140000 pg/m3、1.4pg/m3、100pg/m3 and 250 pg/m3, respectively. PBDEs were the most abundant compounds and their concentrations were three orders of magnitude higher than other compounds. The concentrations of PBDEs in air samples were relatively high compared with the concentrations found in other parts of the world. The detection rate of emerging halogenated organic compounds, including DP, PBBz and PBT, were 100%, indicating an universal environmental pollution.Concentrations of PCBs, OCPs, PBDEs, DP, PBBz and PBT in the pooled serum samples from Weifang were also analyzed in this study. The concentrations of OCPs and PBDEs were found at higher levels than other compounds, with mean concentrations of 1500 ng/g lipid and 240 ng/g lipid, respectively. Emerging halogenated organic compounds, including DP, PBBz and PBT, were detected in all of the pooled serum samples and their mean concentrations were 3.6 ng/g lipid,4.9 ng/g lipid and 1.4 ng/g lipid, respectively. Different relationships were observed between the concentrations of different compounds in serum and the volunteers’ ages, and the concentration distributions with age were closely related to the historic production and usage volumes of each chemical in China. Besides, significant correlations were found between the chemical concentrations in serum and vapor air samples, in serum and particulate air samples and in serum and total air samples, suggesting that inhalation may be an important exposure route for the residents of Laizhou Bay.Concentrations of PCBs, PBDEs and DP were analyzed in individual serum samples from Weifang and Nanning. It showed that the concentrations of these compounds were higher in Weifang serum samples than in Nanning serum samples. Concentrations of five thyroid hormones were also determined in each individual serum sample and we studied the relationships between the halogenated organic compounds and thyroid hormones. The results of multiple linear regression analysis showed that, in Weifang individual serum sample, T3 level is affected by ΣDP and BDE-99, fT3 level is affected by anti-DP, T4 level is affected by L-PCBs and no relationships were found between fT4 or TSH level and the compounds. However, in Nanning individual serum sample, T3 level is affected by BDE-153 and Σ10 PBDEs, fT3 level is affected by PCB-118 and PCB-170, T4 level is affected by PCB-156 and TSH level is affected by Σ10PBDEs. The correlations between the analyte and thyroid hormone concentrations followed different trends in Weifang and Nanning serum samples and this difference may be due to their different exposure level and population characteristics.