[Peculiar remaining of some PCB congeners in the patients with Yusho for more than 30 years].

Concentrations of polychlorinated biphenyl (PCB) congeners, hexachlorobenzene (HCB) and dichloro dichlorophenyl ethylen (DDE) in the blood of Yusho patients (n = 28) were statistically compared with those in the blood of Fukuoka residents (n = 151). The PCB concentrations in the blood of Yusho patients were higher than those of Fukuoka controls and concentration ratios of Yusho/Control were various depending on PCB congeners, being 1.6 on 2,3',4,4',5-pentaCB (# 118), 17.5 on 2,3,3',4,4',5-hexaCB (# 156) and 5.4 on total PCBs. Correlation coefficients between age and concentrations of 7 PCB congeners, HCB and DDE in the blood of Fukuoka residents were significantly positive each other (p < 0.001), while in Yusho patients, the correlation coefficients were positive but various depending on the congeners. However, correlation coefficient between PCB # 118 and PCB # 156 in the Yusho patients was remarkably low, indicating their peculiar accumulative properties in Yusho patients. The concentration of PCB # 118 had been markedly decreased after the ingestion of PCBs and would be metabolized to hydroxylated PCB, which might cause estrogen disturbance in the Yusho patients.