Exposures to polycyclic aromatic hydrocarbons (PAHs) may cause lung and bladder cancer. Exposure monitoring programs have been used in the aluminum smelter industry for decades to decrease the risk of cancer from exposure to PAHs, while other industries such as the offshore industry has never been monitored. Biological monitoring of PAHs incorporates all routes of exposure. Measuring post-shift urinary 1-hydroxypyrene (1OHP), a metabolite of pyrene, is a surrogate for workers' daily PAH exposures, while DNA adducts detected in white blood cells or urothelial cells can reflect chronic exposures to PAHs.
In the first study, we reviewed the scientific literature to identify changes over time in (1) 1OHP levels, (2) DNA-adduct levels, and (3) other contributing factors associated with 1OHP and DNA-adduct levels in the aluminum smelter industry. No trends were observed in 1OHP and DNA-adduct levels. This could be due to variable selection of study populations and poorly identified job tasks which prevent comparison of jobs across plants and times, unassessed worker exposure variability, and the impact of cumulative exposures. Inconsistent findings were also observed in the analysis of CYP1A1, GSTM1 and GSTP1 polymorphisms and their effect on biomarker levels. Future studies should be aimed at follow-up in workplaces where dermal and inhalation exposure interventions have been employed.
In the second study, we explored the possibility of exposure to PAH derivatives in aluminum smelters such as fluorine-substituted PAHs (F-PAHs). Coal tar is used as an anode and cryolite (Na3AlF6) is the solvent in the electrochemical reaction in a smelter. The aim of this study was to determine whether F-PAHs were actually formed in aluminum smelters. Settled dust samples (n = 5) were extracted using established PAH extraction methods. Detection methods were reverse phase high performance liquid chromatography with photodiode array ultraviolet detection (HPLC/PDA), and gas chromatography with mass spectroscopic detection (GC/MS). F-PAHs were not found in any of these samples, but only unsubstituted analogs; however the sample size was too small to state unequivocally that F-PAHs were not present. Thus, the need for further characterization of the complex chemical mixtures to which aluminum smelter workers are exposed is still needed.
In the third study, we studied PAH exposures in offshore workers (n=42). Our objectives were to: (1) Compare differences in mean post- and pre-shift urinary 1OHP levels between exposed and non-exposed workers, after including covariates such as smoking, job, and age; and (2) Compare differences in post-shift urinary 1OHP levels between exposed workers, after controlling for pre-shift 1OHP levels, smoking, job, and age. Analysis of covariance was used and models included pre-shift values and covariates. We found that (1) Post-shift 1OHP levels were significantly higher in the exposed workers compared to the controls, after controlling for age and pre-shift 1OHP levels; and (2) Tank workers and process operators did not show statistically significant different post-shift 1OHP levels, after controlling for age and pre-shift 1OHP levels. Altogether, this study indicates the presence of a low level PAH exposure among offshore production workers.