[Levels of carcinogenic, polycyclic aromatic hydrocarbons in human and animal tissues. IIIrd communication (author's transl)].

(1) The mean content in benzypyrene (bp) of human pulmonary tissue amounts to 0.2 mug./100 g. of dry substance. As in all other organ tissues, however, the content differs with the age of the individual: in infants, we find maximum concentrations, in the medium age groups the levels decline and rise once more with increasing age. (2) No increase in the 3,4-benzpyrene levels (average: 0.2 mug./100 g. of dry substance) will be found in tissues with high cellular proliferative activity, such as exocrine and endocrine glands (pancreas, testicles, thyroid gland, adrenals, mammary glands, as well as bone marrow). (3) In human adipose tissue, as well as in that of pork and beef, the 3,4-benzpyrene levels are found to be exceedingly low. With values of 0.1 mug./100 g, the average concentrations lie markedly below the organ tissue levels. Hence, this class of noxious substances in not stored in the adipose tissue. (4) Both in man and in animals (pig, fowl), the 3,4-benzyprene concentrations consistently exceed the average values during early postnatal life. (5) This relatively high concentration of bp in early infancy is due to exogenous factors and is not the expression of biogenous synthesis, as has been demonstrated in examinations of the environmentally influenced embryonic development of the chick. Throughout the entire development of the embryo within the hen's egg, the benzpyrene levels remain constant. Only when the chickens have been hatched out do the benzyprene levels rise significantly. Thus, the low 3,4-benzpyrene levels detected in all human and animal organ tissues prove to be the result of the interplay of exogenous environmental loading and individual capability of eliminating this substance.