Polychlorinated Biphenyl Congeners in Adipose Tissue Lipid and Serum of Past and Present Transformer Repair Workers and a Comparison Group

The concentrations of individual PCB's were determined in both serum and adipose tissue lipid from 35 transformer repair workers currently exposed to PCBs, mainly Aroclor 1260, 17 previous transformer repair workers, and 56 comparison workers never occupationally exposed to PCBs. The analysis used fused-silica capillary gas chromatography with electron capture detector (FSCGC/ECD) and FSCGC with negative ion chemical ionization mass spectrometry to verify PCB congener levels. Eighty-nine PCB peaks were identified and confirmed. More congeners were detected in adipose tissue. In serum approximately 50% of peaks were below the level of detection. Statistical techniques to account for left and interval censoring allowed comparison of concentration distributions even where data were incomplete. We found that unquantifiable levels were unlikely to contribute substantially to the true values for total [PCBs] over and beyond the contribution of the measured values. However, the total serum [PCBs] determined by FSCGC/ECD greatly exceeded that from standard packed cell gas chromatography (PCGC/ECD). The underestimation was less marked for adipose samples. In serum the total [PCBs] was highest in currently exposed workers and lowest in unexposed workers, with past-exposed workers clearly intermediate. In adipose tissue [PCBs] in the currently exposed group was much higher than in the other two groups, in whom the distribution of results was broadly similar. In all worker groups hexachlorinated and heptachlorinated species predominated followed by octachlorinated and pentachlorinated. The relative distribution of individual PCB congeners in the three groups was similar although the amounts varied. The seven major peaks in serum and adipose tissue were 2,3,5,6,3',4',5'/2,3,4,5,2',4',5' hepta-CB; 2,3,4,2',3',5' hexa-CB; 2,4,6,3',4',5'/2,4,5,2',4',5'/2,3,4,5,2',5' hexa-CB; 2,3,4,5,2',3',4' hepta-CB; 2,3,4,5,2',3',5',6'/2,3,4,5,6,2',3',5', octa-CB; 2,4,5,3',4',/3,4,5,2',3' penta-CB; and 2,3,4,2',3',4'/2,3,5,6,2',4',5'/2,3,4,5,2',4',6' multi-CB. The distribution of PCB peaks in our populations differs from that in capacitor workers (exposed to less highly chlorinated PCBs) and from Yu-Cheng patients suggesting differing toxic potentials from PCBs in these three circumstances.