Bioassay monitoring of waste PCB samples during chemical destruction treatments.
Capacitor oil samples (PCBs > 90%wt) were treated in a bench scale experiment to investigate the destruction of PCBs during chemical destruction processes (a catalytic hydrodechlorination treatment with palladium carbon and additional treatment with potassium tert-butyloxide). Using those results, this study confirmed the decrease of PCBs and other undesirable dioxin-like compounds such as PCDD/Fs in treated samples during the treatment. Dioxin-responsive chemical-activated luciferase expression (DR CALUX) AhR reporter gene bioassay was used to evaluate dioxin-like activity in the samples. During the treatment, the efficiency for PCB capacitor oil was around 99.99% or more in WHO-TEQ and CALUX-TEQ, whereas the sum of PCBs was reduced at a resulting efficiency of >99.9999%. In this study, a new cleanup procedure for separating PCBs from the mineral oil matrix was also developed for DR CALUX. The procedure consists of dimethylsulphoxide partitioning followed by silica gel-44% sulphuric acid reflux treatment and activated carbon chromatography. With the cleanup, CALUX-TEQ values were in good agreement with WHO-TEQ values and were as much as 3.3 times higher than WHO-TEQs for untreated/treated PCB-containing insulating oil samples. The DR CALUX results of mineral oil samples containing various PCB concentrations of 0.5-50 mg/kg (corresponding WHO-TEQs: 0.012-1.2 microg-TEQ/g) also correlated well with WHO-TEQs (CALUX-TEQ/WHO-TEQ ratio = 1.0-3.0), which was consistent with the theoretical quantification limit of the CALUX. These results supported the validity of the proposed clean-up method.
Takigami
H
H
Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, Ibaraki, Japan. takigami@nies.go.jp
Behnisch
P A
PA
Shiozaki
K
K
Ohno
M
M
Sakai
S I
SI
D000818:Animals; D001681:Biological Assay / Q000379:methods*; D000440:Butanols / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D045744:Cell Line, Tumor; D004147:Dioxins / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D007220:Industrial Waste; D010165:Palladium / Q000737:chemistry; D011078:Polychlorinated Biphenyls / Q000737:chemistry*; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D051381:Rats; D013463:Sulfuric Acid Esters / Q000737:chemistry; D013464:Sulfuric Acids / Q000737:chemistry
D000440:Butanols; D004147:Dioxins; D007220:Industrial Waste; D000072317:Polychlorinated Dibenzodioxins; D013463:Sulfuric Acid Esters; D013464:Sulfuric Acids; D010165:Palladium; D002244:Carbon; C077664:tert-butoxide, potassium; D011078:Polychlorinated Biphenyls; C007482:dimethyl sulfate; C033158:sulfuric acid