Concentrations of polychlorinated biphenyls in blood collected from Yusho patients during medical check-ups performed from 2004 to 2007.

To elucidate the exposure levels of polychlorinated biphenyls (PCBs) for Yusho patients, we conducted a congener-specific analysis of polychlorinated biphenyls (PCBs) in blood collected from 242, 237, 300, and 96 Yusho patients during medical check-ups performed from 2004 to 2007, respectively, and in samples from 74, 113, 125, and 148 Yusho-suspected persons during those same years, respectively, and compared the individual congener concentrations of PCBs among the groups of Yusho patients, Yusho-suspected persons, and normal controls with the concentrations previously reported. Among the 209 PCB congeners, 8 congeners of mono-ortho PCBs and 56 congeners of non-dioxin-like PCBs were identified in the blood of Yusho patients and Yusho-suspected persons. Among the PCB congeners measured in the present study, hexaCB-153, hexaCB-138, heptaCB-180, and heptaCB-182/heptaCB-187 showed high ratios to total concentrations of 64 PCB congeners detected in the blood of Yusho patients and Yusho-suspected persons from 2004 to 2007, and the profiles of the major congeners were the same as those obtained in normal controls. With respect to the minor congeners of PCBs, several differences were observed among the three groups. The sums of the concentrations of 64 PCB congeners in the blood of Yusho patients from 2004 to 2007 were 645, 760, 667, and 510 ng g(-1) lipid for each year, respectively, and the concentrations were 1.5, 1.8, 1.5, and 1.2 times higher than those of normal controls for each year, respectively. Those of the Yusho-suspected persons were approximately 0.8, 1.1, 0.9, and 1.0 times higher than those of normal controls for each year, respectively. The ratios of heptachlorinated biphenyls (heptaCBs) to the total concentrations of 64 PCB congeners in the blood of Yusho patients and Yusho-suspected persons from 2004 to 2007 tended to be slightly higher than those in the normal controls. From the results comparing the concentrations of 64 PCB congeners in the blood between Yusho patients and normal controls, the concentrations of hexaCB-156, hexaCB-157, heptaCB-181, and heptaCB-189 for Yusho patients were 3.4, 3.8, 3.9, and 3.8 times, respectively, 3.9, 4.1, 3.9, and 4.4 times, respectively, 3.6, 3.9, 5.0, and 4.1 times, respectively, and 2.3, 2.5, 2.7, and 2.9 times higher than those of the normal controls for each year from 2004 to 2007, respectively. These results indicated that Yusho patients still have higher concentrations of hexaCB-156, hexaCB-157, heptaCB-181, and heptaCB-189 in their blood than do unaffected people, even though over 35 years have passed since the outbreak of Yusho. These four congeners can therefore be considered to be the most important congeners for evaluating the PCBs exposure of Yusho patients.