Comparison of PCDD/F and coplanar PCB concentrations in Japanese human adipose tissue collected in 1970–1971, 1994–1996 and 2000

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and coplanar biphenyls (Co-PCBs) were determined in Japanese human adipose tissues. Temporal trends were assessed by comparing data collected during 1970–1971, 1994–1996 and 2000. Mean TEQ levels of PCDD/Fs in human adipose tissue showed a significant decrease from 31.6±9.2 pg-TEQ/g fat wt in 1970–1971 to 11.9±7.4 pg-TEQ/g fat wt in 2000, and coplanar PCBs decreased from 35.4±21.9 pg-TEQ/g fat wt in 1970–1971 to 15.3±8.2 pg-TEQ/g fat wt in 2000. However, some PCB congener concentrations did not change during this time. A comparison of data using the latest PCB–TEQ showed no significant changes. Therefore, research on source characterization and monitoring of short-term temporal trends on these compounds should be carried out continuously.