Levels and distributions of polychlorinated biphenyls in sewage sludge ofurban wastewater treatment plants
GUO Li , ZHANG Bing , XIAO Ke , ZHANG Qinghua , ZHENG Minghui
DOI:
Received April 23, 2008,Revised June 15, 2008, Accepted , Available online
Volume 21,2009,Pages 468-473
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Concentrations of polychlorinated biphenyls (PCBs) have been measured in sewage sludge samples from 8 urban wastewater
treatment plants in Beijing, China. The PCB congeners were analyzed by isotope dilution high resolution gas chromatography/high
resolution mass spectrometry method. The concentration of PCBs ranged from 65.6 to 157 ng/g dry weight (dw), with a mean value
of 101 ng/g dw. The dioxin-like PCB WHO-TEQs (World Health Organization–Toxic Equivalents) of the sludge were lower than 1 pg
/g dw. Consequently, all the concentrations of PCBs in sludge samples were below the upper limit for land application according to
the Chinese legislation law for agriculture use. The PCB homologue profiles in sludge samples were dominated by tri-CBs and tetra-
CBs. Similar distributions have been found in one of the Chinese PCB commercial products. The patterns of dioxin-like and indicator
congeners observed in this study were quite similar in all samples. The predominant congener for dioxin-like and indicator PCBs were
PCB-118 and PCB-28, respectively, while PCB-126 had the highest TEQ value.
