Trace analysis of 3-hydroxy benzo[a]pyrene in urine for the biomonitoring of human exposure to polycyclic aromatic hydrocarbons

Determination of benzo[a]pyrene (BaP) metabolites in urine can provide direct insight into recent exposure to BaP integrated from all uptake routes. In order to detect 3-OH BaP in human urine after exposure to BaP at the workplace, extremely sensitive methods need to be developed. In this paper, a new extraction method is presented, and two laserbased fluorescence techniques are evaluated. Using HPLC with laser-induced fluorescence detection, a detection limit of 8 ng/L was obtained. With laser-excited Shpol'skii spectrometry after chemical derivatization, 3-OH BaP could be detected at even a 0.5-ng/L concentration. In a pilot study, urine samples from coke-oven workers and from occupationally nonexposed control persons were analyzed. In the control samples, the average 3-OH BaP concentration was 8.3 ng/L; the 3-OH BaP concentrations were found to be highly correlated (r² = 0.89) with urinary 1-OH pyrene, a widely used biomarker for polycyclic aromatic hydrocarbon (PAH) exposure. Significantly elevated 1-OH pyrene concentrations were measured in urine samples from coke-oven workers, but in most samples a corresponding increase of 3-OH BaP was not observed. Possible explanations for this discrepancy are discussed.