Levels of PCDD/PCDF in blood fat as indices of the PCDD/PCDF body burden in humans.

The levels of PCDD/F in blood fat are similar to those in body fat and in milk fat of lactating women. Therefore, the levels of PCDD/F in blood fat can be used as an index of the individual PCDD/F body burden in humans. In order to evaluate the PCDD/F background exposure levels of the German population, blood samples collected from 95 subjects (age 12-82 years) living in a rural area of North-West Germany were analysed for PCDD/F. The median 2,3,7,8-TCDD toxicity equivalents (TE) were 40.8 pg I-TE/g blood fat and the 95th percentile was 82.1 pg I-TE/g blood fat. The TE levels in blood fat show a marked increase with age, which reflects the pronounced accumulation of PCDD/F in the human body throughout the entire lifetime. Considering single congeners, significant differences in the age-related increase were noted. Using age-specific reference values derived from this study the levels of PCDD/F in blood fat of individuals environmentally exposed to PCDD/F under different circumstances were evaluated.