Analysis of Polycyclic Aromatic Hydrocarbon Exposure in Road Paving Workers

Road-paving workers are potentially exposed to many occupational hazards, including polycyclic aromatic hydrocarbons (PAHs) through the inhalation of bitumen fumes and dermal contact with bitumen. PAHs are the product of the incomplete combustion of organic materials, and may be found in wood smoke, grilled meats, cigarette smoke, and bitumen (asphalt) fumes. Road paving workers are at an increased risk for lung, skin, and bladder cancer. One method of measuring exposure to combined inhalation and dermal sources of bitumen is biological monitoring. 1-Hydroxypyrene (1-HP) is a metabolite of the PAH pyrene. 1-HP has a half-life of 21 hours in the human body and can be measured in urine using high-performance liquid chromatography (HPLC). Urine samples were obtained from six road-paving workers in Germany and analyzed for 1-HP. The samples were collected over a six-week period, and included both pre- and post-work shifts, as well as during a pre-employment medical evaluation. Pre- and post- shift concentrations of 1-HP from weeks 1 and 6 were compared using a paired t-test to determine whether the post-shift concentrations of 1-HP were greater than pre-shift concentrations. The mean of the post-shift levels of urinary 1-HP was found to be 3 times higher than the mean of the pre-shift levels. The probability that the post-shift concentrations of 1-HP exceeded the pre-shift concentrations of urinary 1-HP was 0.047, which is statistically significant at the 95% confidence level. This observed increase in mean urinary 1-HP levels for pre-shift versus post-shift samples supports the hypothesis that road-paving workers have significant exposures to PAHs and that 1-HP levels can serve as a biological marker for such occupational exposures.