Studies on the Compounds Related to PCB (V)

It was considered that all the chlorine in Kanemi rice oils which caused the “Yusho” was derived from PCB, and the PCB concentrations were calculated from the concentration of total chlorine in the oils in 1969 to 1970.However, in this study, the PCB concentrations in the oils were barely as 1/3 to 1/7 times as those which were calculated from the concentration of total chlorine. The difference between these two PCB levels suggests that unknown organochlorinated compounds will exist in large quantities in the oils. The oils were saponified, extracted with n-hexane, and the extracts were cleaned up by gel permeation chromatography and thin layer chromatography. Then, unknown organochlorinated compounds were analyzed by ECD-GC, GC-MS and neutron activation analysis. On 2% OV-210 column, the gas chromatograms of these compounds showed many peakes with later R. T. than that of PCT (Aroclor 5460). GC-MS analysis revealed that the compounds were composed of penta- to deca-chlorinated quaterphenyl, hepta- to nona-chlorinated quaterphenyl ether and penta- to octa-chlorinated terphenyl. Polychlorinated quaterphenyls occupied quantitatively the most of the compounds. The result of neutron activation analysis showed a surprising fact, i. e., in Kanemi rice oils, which were manufactured on Feb. 5, 9 and 10 in 1968, these unknown organochlorinated compounds were contained 1.1, 3.6 and 4.1 times, respectively, more than PCB amounts. Therefore, it became clear that the causal compounds of the “Yusho” were not only PCB and PCDF but also the higher molecular chlorinated compounds.