PCBs and PCDD/DFs in waste oil illegally dumped and neglected for more than 20 years

Takashi Honda, Mitsuhiro Wada, Kenichiro Nakashima
2009 Journal of Environmental Science and Health. Part A: Toxic/Hazardous Substances and Environmental Engineering  
Quantification of polychlorinated biphenyls (PCBs), polychlorinated-dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in waste oil by high resolution gas chromatography-high resolution mass spectrometry (HRGC-HRMS), and profiling of their congeners and homologues were described. Waste oil packed in drums which were estimated to have been exposed to the weather for more than 20 years were found by the illegal dumping patrol in 2006. PCBs were detected in all of 12 waste oil
more » ... of 12 waste oil samples examined, with concentrations in the range of 0.0032-22 µg/g. The main pollution sources of the waste oil samples were presumed to be KC300, KC400 and/or KC500 by principal component analysis (PCA) and a chemical mass balance (CMB) method. The concentrations of PCDDs and PCDFs (PCDD/DFs) in the illegally-dumped waste oil ranged from 1.1 to 360 pg/g and 1.3 to 110 pg/g, respectively. The ratios of toxicity equivalency quantity (TEQ) of PCDDs and PCDFs to Co-PCBs were lower than those of Yusho rice oil. Consequently, it was determined that even after 20 years of exposure to the weather, no PCB denaturation occurred. However, it was confirmed that low-chlorinated biphenyls in corroded drums would have evaporated into the atmosphere. After addition of a cleanup spike consisting of seventeen [ 13 C]-labeled 2,3,7,8-chlorine substituted PCDD/DFs (Kanto Chemical Co.) into 2.5 g of the waste oil in n-hexane, the sample was extracted with n-hexane-saturated DMSO. Then, this step was repeated three times. The DMSO phase was back extracted with n-hexane and n-hexane-extracted water. This back extraction was performed triplicate. The n-hexane phase was treated with 30 mL of 2 M potassium hydroxide, and washed with n-hexane-extracted water. Thereafter, the sample purification was performed according to the Japanese standard method [14] as follows; the n-hexane phase was treated with concentrated sulfuric acid, and washed with n-hexane-extracted water. The concentrated n-hexane phase was cleaned up using the multi-layer silica gel column chromatography. This column was eluted with 200 mL of n-hexane. The eluate was loaded onto the activated carbon-dispersed silica gel reversible column (Kanto Chemical Co.), and successively eluted with 50 mL of n-hexane and 40 mL of n-hexane containing 25% dichloromethane for collecting mono-ortho-coplaner PCBs. The initial fraction of n-hexane was discarded. Then, the column was reverse eluted with 100 mL of toluene for collecting PCDD/DFs and non-ortho-coplaner PCBs. The both mono-ortho-coplaner PCBs fraction and the PCDD/DFs and non-ortho-coplaner PCBs fraction were concentrated in vacuo to 25 µL. As a result, recovery standards consisting of two [ 13 C]-labeled congeners of PCDD/DFs (Kanto Chemical Co.)
doi:10.1080/10934520902847661 pmid:19412846 fatcat:pyr62t34pjg5ndcsplikc3kuh4