Can Urinary OH-PAHs Be Used to Predict Cancer Risk Associated with Personal Exposure to PAHs?

Abstract

P-140 Abstract: Polycyclic aromatic hydrocarbons (PAHs), a group of known or suspected carcinogenic compounds, are produced during pyrolysis or incomplete combustion of organic materials. PAHs are ubiquitously present in multiple environmental media such as air, food, cigarette smoke and certain products. Although a number of biomarker studies have been carried out for assessing PAH exposures, so far the biomarker-based studies have not contributed to the identification and quantification of cancer risk. One of the biomarkers widely studied is urinary 1-hydroxyl-pyrene (1-OH-Py), a metabolite of pyrene. Pyrene is a relatively abundant but noncarcinogenic compound in the PAHs family. To date few studies have focused on urinary 3-OH-BaP, a direct metabolite of carcinogenic benzo(a)pyrene. The purpose of this paper is to study the feasibility of using 1-OH-Py or/and 3-OH-BaP to predict human exposure dose to PAHs and associated cancer risk. In this study, 100 non-smoking adults were selected as subjects. Among them, 50 were coke oven workers in various jobsites, 25 were administrators in a steal factory, and 25 were non-factory employees in offices far away from factory. Their 24-hr personal air samples, 24-hr dietary samples and every void of urine samples during this 24-hr study time were collected. Fourteen individual PAHs in air and food samples as well as 1-OH-Py and 3-OH-BaP in urine samples were respectively analyzed using HPLC-fluorescence techniques. The results showed that the total daily exposure dose to PAHs in coke oven workers was 17.94 ± 30.10(mean ± SD)μg/day, significantly higher than 1.27 ± 2.23 ug/day in the general group. The concentration of urinary 1-OH-Py in coke oven workers was 3.19 ± 4.10 μmol per mol creatinine, significantly higher than 0.19 ± 0.27 μmol/mol. in the general group. We found positive quantitative relationships between urinary 1-OH-Py and personal exposure dose to PAHs. Thus urinary 1-OH-Py concentrations can be used to estimate PAH cancer risks. On the contrary, the concentration of urinary 3-OH-BaP in coke oven workers was 0.04 ± 0.02 μmol/mol, significantly lower than 0.09 ± 0.07 in the general group. This may reflect reduced PAH-detoxification capability, due to long-term exposure to high levels of PAHs, of the coke oven workers. Therefore, the PAH body burden may be better predicted using both 1-OH-Py and 3-OH-BaP than solely using 1-OH-Py. We propose a cancer risk assessment model based on the ratio of urinary 1-OH-Py to 3-OH-BaP. Key Words: Polycyclic aromatic hydrocarbons(PAHs); Biomarker; Urinary 1-OH-Py; Urinary 3-OH-BaP.