Selective retention of PCDDs and PCDFs in mammals: A multiple cause problem

The selective retention of only a few congeners out of the groups of PCDDs and PCDFs in living organisms is surprising, because many processes, e.g. waste burning in municipal incinerators, PCB and pentachlorophenol production lead to the formation and release of a whole spectrum of congeners. Such a structural relationship for 2,3,7,8-substituted congeners has been found for instance in human adipose tissue liver and mothers milk. In the following it is illustrated that at least two factors, metabolism as well as protein binding, are probable causes for this phenomenon.