Analysis of faeces for benzo[a]pyrene after consumption of charcoal-broiled beef by rats and humans

The excretion of benzo[a]pyrene (B[a]P) and its metabolites in faces were studied in rats after administration by gavage of varying doses of ¹⁴C-labelled B[a]P and the excretion of unchanged B[a]P in rat and human faeces was investigated after feeding charcoal-broiled meat containing B[a]P. When rats were given ¹⁴C-labelled B[a]P in doses of 0·04 μmol (10·2 μg), 0·4 μmol and 4·0 μmol/rat, 74-79% of the dose was excreted in the faeces in the first 48 hr; unchanged B[a]P in faeces amounted to 13·0, 7·8 and 5·6%, respectively, for the three doses studied. Faecal metabolites included 3-hydroxy-B[a]P, 9-hydroxyB[a]P, B[a]P-3,6-dione, B[a]P-1,6-dione and trace amounts of 4,5-dihydro,4,5-dihydroxyB[a]P, and 7,8-dihydro-7,8-dihydroxyB[a]P. When rats were fed charcoal-broiledhamburger containing 52·7 μg B[a]P/kg, 11% (0·06 μg/rat) of the B[a]P consumed was excreted unchanged in the faeces. When humans ate meals containing charcoal-broiled meat (24·2 μg B[a]P/kg) B[a]P was not detected in the faeces, despite the fact that each person consumed 8·6 μg B[a]P.