Polybrominated dibenzo-p-dioxins, dibenzofurans, and diphenyl ethers in Japanese human adipose tissue

Human adipose samples collected in Tokyo, Japan in 1970 and 2000 were analyzed for the presence of polybrominated dibenzo-p-dioxins (PBDDs), dibenzofurans (PBDFs), and diphenyl ethers (PBDEs), and the concentrations in the two groups were compared. As far as we know, the concentrations of the PBDD/Fs in adipose tissue from the general Japanese population are reported for the first time. Three PBDD/F congeners were found in the following adipose tissues: 2,3,7,8-TeBDD, 2,3,7,8-TeBDF, and 2,3,4,7,8-PeBDF. The median concentrations (ranges) of three PBDD/Fs in 1970 and 2000 were 5.1 (3.4-8.3) and 3.4 (1.9-5.3) pg/g lipid wt (l.w.), respectively. For PBDEs, seven PBDE congeners were determined in the following samples: 2,4,4'-tribromodiphenyl ether (BDE-28), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), 2,2',4,4',6-pentabromodiphenyl ether (BDE-100), 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153), 2,2',4,4',5',6-hexabromodiphenyl ether (BDE-154), and 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE-183). Median concentrations (ranges) of PBDEs showed a significant increase from 29.2 (6.8-78.4) pg/g l.w. in 1970 to 1288 (466-2,753) pg/g l.w. in 2000. BDE-47, the major congener of PBDEs, was 56.2% and 35.6% of the total in 1970 and 2000, respectively, whereas the BDE-153 was < 1% and 29.7% of the total in 1970 and 2000, respectively. This may indicate that the source of PBDEs had changed during this period. Further analysis of archived human samples from 1970 to 2000 is needed to describe the details of the contamination trends of PBDD/Fs and PBDEs in the Japanese population. Furthermore, PBDD/F monitoring, particularly 2,3,7,8-TeBDD and 2,3,7,8-TeBDF, may give more toxicological information based on TeCDD toxic equivalents (TEQs).