Analysis and occurrence of polychlorinated biphenyls and polycyclic aromatic hydrocarbon in sludge dredged from a serious eutrophic lake, China

摘要

Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbon (PAHs) belong to the two groups of the persistent organic pollutants (POPs). Since their low-water solubility, sludge became the huge reservoir and potential secondary source of PCBs and PAHs. An analysis method of PCBs and PAHs in sludge dredged from a serious typical eutrophic lake was improved. The analysis process was consisted of the accelerated solvent extraction (ASE), solid phase extraction (SPE) and gas chromatography-mass spectrometry Triple Quad (GC-MS-MS). The ASE procedures were performed by optimizing three key process factors, such as extraction solvent, extraction temperature and holding time. For SPE, various parameters, such as SPE phase cartridge and elution solvent, were investigated. The method achieved good repeatability and reproducibility with relative standard deviations (RSDs) less than 12% for PCBs and PAHs in sludge. The established method was successfully applied to the analysis of PCBs and PAHs in the sludge dredged from Lake Dianchi as a serious typical eutrophic lake in China. The concentration levels of ΣPCBs and ΣPAHs were up to 80 and 11070 ng g~(-1) dry weight. The dominating compositions of PCBs were TetraCB, TriCB, HexaCB and PentaCB, whereas the high molecular weight 4, 5 and 6 rings of PAHs were the main compounds. The study can provide more comprehensive and fundamental technology and data for risk assessment of PCBs and PAHs in sludge of eutrophic lake.