Assessment of the bioavailability of PAHs in rats exposed to a polluted soil by natural routes: Induction of EROD activity and DNA adducts and PAH burden in both liver and lung

In order to assess bioavailability of polycyclic aromatic hydrocarbons (PAH s) present in soils, male laboratory rats were exposed to litters of contro l and polluted soils. After 88 +/- 2 h of exposure, several biomarkers were measured in both liver and lung. When rats were exposed to STV soil, conta minated by a mixture of at least 13 PAHs, (1) only 2 or 3 PAH compounds wer e detected in liver and lung; (2) cytochrome P450-dependent monooxygenase a ctivity, followed by 7-ethoxyresorufin O-deethylase (EROD) activity measure ment, was highly induced in liver (13-fold-induction) and lung (up to 78-fo ld); and (3) DNA adducts were significantly increased. For what concerns so il artificially contaminated by only one PAH (phenanthrene or B[a]P), FROM activity was not or fewly induced, respectively. These results demonstrate the occurrence of a high bioavailability of PAHs to mammals in natural cond itions of exposure. First results concerning DNA adducts must be profounded , but they already show that a short exposure of mammals to PAM-polluted so ils can lead to potential genotoxic effects. EROD activity can be used as a sensitive biomarker in both liver and lung of rats maintained on litters o f soils in the laboratory, and such a test can be used routinely to contrib ute to risk assessment. (C) 1999 Academic Press.