Formation of PCDD/Fs and PCBs in the process of production of 1,4-dichlorobenzene.
The occurrence and distribution of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in a typical process of production of 1,4-dichlorobenzene (p-DCB) were investigated systematically in this study. P5CDFs and H6CDFs were the main congeners of PCDD/Fs, while only low levels of other PCDD/Fs were detected in the samples. The concentrations of PCBs were up to 4614 ng/g in the semi-manufactured products, and 1797 ng/g in the product p-DCB. It was also found that high chlorinated PCB congeners increased with the further chlorination. The levels of PCDD/Fs decreased obviously in the purification process, while PCBs could not be removed effectively. Polychlorophenols and other important dioxin precursors (1,4-dichloro-2-phenoxybenzene and 2-phenyl-2',5,5'-trichlorophenol) were also analyzed. Polychlorophenols which ortho- and para-positions of the hydroxyl were substituted by chlorine were the main congeners. In addition, a possible pathway of the formation of PCDD/Fs and PCBs in the production of p-DCB was presented. The results of this article suggest that re-estimation on the risk of using p-DCB products, especially the products for daily use such as mothballs, is expected.
Liu
Wenbin
W
Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
Zheng
Minghui
M
Wang
Dongsheng
D
Xing
Ying
Y
Zhao
Xingru
X
Ma
Xiaodong
X
Qian
Yong
Y
D001572:Benzofurans / Q000737:chemistry*; D002617:Chemical Industry; D002722:Chlorobenzenes / Q000737:chemistry*; D004147:Dioxins / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D008420:Manufactured Materials / Q000032:analysis; D011078:Polychlorinated Biphenyls / Q000737:chemistry*
D001572:Benzofurans; D002722:Chlorobenzenes; D004147:Dioxins; C018511:4-dichlorobenzene; D011078:Polychlorinated Biphenyls