Urinary excretion of 3-hydroxy-benzo[a]pyrene after percutaneous penetration and oral absorption of benzo[a]pyrene in rats.

A method for the monitoring of exposure to benzo[a]pyrene was applied to rat urine samples. Benzo[a]pyrene was administered percutaneously and orally with repeated doses of 10, 20 and 50 mumol/kg body wt. At low dose levels, the urinary excretion of 3-OH-benzo[a]pyrene was higher after percutaneous treatment than after oral administration. The excretion of 4 benzo[a]pyrene metabolites, including 3-OH-benzo[a]pyrene, is faster after oral administration. The percutaneous absorption of small doses of benzo[a]pyrene appears to be greater than the oral absorption.