A guidance value of 1-hydroxypyrene in urine in view of acceptable occupational exposure to polycyclic aromatic hydrocarbons

In order to assess the point-of-departure for limit setting, cross-sectional studies were searched for that report on the response of early genotoxic effects in white blood cells of workers that could be related to the degree of PAH-exposure (expressed as 1-hydroxypyrene in urine). Nine cross-sectional studies were traced that met these requirements. From each study, the concentration of 1-hydroxypyrene in end-of-shift urine samples was determined, at which no genotoxic effects was found. From 4 out of 9 studies a no-observed genotoxic effect level could be derived, the lowest level was 1.0 μmol/mol creatinine. This limit level is recommended as a state-of-the-art guidance, valid when the PAH-profile in the work environment is similar to that of coke oven with a typical pyrene/BaP ratio of 2.5. For work environments with a deviating PAH-profile an adjustment procedure with the pyrene/BaP ratio is suggested.