Dermal exposure to polycyclic aromatic hydrocarbons among road pavers

Objectives: Dermal exposure to polycyclic aromatic hydrocarbons (PAHs) and the role of an industrial by-product, coal fly ash, on workers' PAH exposure were investigated during stone mastic asphalt (SMA) paving and remixing. Methods: PAH exposure was measured at eight sites during the laying of SMA containing coal fly ash or limestone (conventional SMA) as the filler. Six of the surveys were carried out during SMA paving and two during remixing of SMA (hot recycling at the paving site). Dermal PAH exposure was measured by hand washing (using sunflower oil and wiping with Kleenex tissues) before and after the work shift, and by placing exposure pads on the workers' wrists during the work shift. The analyses included 15 native PAHs from the hand-washing samples determined using high-performance liquid chromatography equipped with a two-channel fluorescence detector and 16 native PAHs and four methylated PAHs from the exposure pads using gas chromatography with mass-selective detection. Results: The PAH results obtained using the pad and hand-washing methods (concentrations after the work shift) were equivalent and showed a strong correlation (r = 0.757, P < 0.001, N = 23 for total PAHs). There was a statistically significant difference between pre- and post-shift samples as measured by hand washing. The skin contamination by PAHs was significantly higher (P < 0.01) during remixing than during SMA paving. The variation in PAH contamination on the skin explained more of the variation in the excretion of urinary 1-hydroxypyrene and phenanthrols than the variation in the respiratory PAH concentrations. Conclusions: The industrial by-product investigated in asphalt, coal fly ash, had no statistically significant effect on the workers' dermal PAH exposure. The dermal exposure of paving workers to PAHs was higher during remixing than during SMA paving.