Biomarkers of Polycyclic Aromatic Hydrocarbon Exposure in German Coke Oven Workers

Introduction
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants. Coke oven workers are PAH-exposed and at increased risk for lung and urinary bladder cancer. 1-hydroxypyrene (1-HP) is a PAH urinary metabolite used to estimate exposure in occupational and environmental settings. The elimination kinetics of 1HP suggest that pre-shift morning samples might predict chronic PAH exposure. PAH also bind to DNA and DNA adduct levels represent metabolism to genotoxins and cumulative exposure for the lifespan of the sampled cells. We hypothesized that urinary 1-HP and DNA adduct levels in exfoliated urothelial cells from pre-shift urine samples of coke oven workers will vary by job, smoking status, and job duration.

Methods
Pre-shift urine samples were collected from 32 coke oven workers. In brief, the samples were filtered to remove cellular components which were reserved for DNA adduct analysis. 1-HP levels were determined by HPLC using a fluorescence detector at an excitation and emission wavelengths of 242 and 388 nm, respectively. DNA was extracted from the isolated urothelial cells and analyzed for adducts using 32P-postlabeling.

Results
The majority of workers (28 of 32) had pre-shift 1HP levels greater than the ACGIH post-shift recommendation. DNA adduct levels were also elevated. Occupational exposure overshadowed smoking. Job duration was a statistically significant predictor of 1-HP level, consistent with the idea that pre-shift 1HP values indicate chronic exposure . 1-HP also was also correlated significantly with one DNA adduct suggesting that PAH exposure was responsible for this adduct in exfoliated urothelial cells. Levels in top oven workers and top oven workers with side oven workers were significantly elevated compared to the supervisor control group.

Discussion
This is the first study to show a relationship between a PAH urinary metabolite and DNA damage in the target organ of coke oven workers. Future studies will aim at reducing exposure using these tools.