Biological monitoring of environmental exposure to polycyclic aromatic hydrocarbons in subjects living in the vicinity of a creosote impregnation plant

Objective: This study was undertaken to evaluate the environmental exposure to polycyclic aromatic hydrocarbons (PAHs) in nonsmoking adult subjects li ving in the vicinity of a creosote impregnation plant in Delson, Canada. Ur inary metabolites of naphthalene, alpha- and beta -naphthol, and pyrene met abolite 1-hydroxypyrene (1-OHP), were used as biomarkers of exposure. Metho ds: Morning and evening urine samples were collected in mid-August from 30 exposed individuals living at a distance of 50-360 m downwind of the plant and from a control group in the adjoining municipality residing at a distan ce of 1.9-2.7 km upwind of the plant. Metabolites were measured by gas chro matography/mass spectrometry. Results: Excretion values of alpha- and beta -naphthol were significantly higher in the exposed group than in controls ( P < 0.04), after accounting for possible confounding variables by multivari ate analyses. The respective geometric mean concentrations (5th and 95th pe rcentiles) of alpha -naphthol for the exposed and nonexposed groups were 2. 04 (0.55-6.00) and 1.37 (0.39-7.02) mu mol/mol creatinine for evening sampl es, and 2.49 (0.77-8.43) and 1.17 (0.37-6.88) mu mol/mol creatinine for mor ning samples. Corresponding values for fl-naphthol were 1.78 (0.82-3.67) an d 1.36 (0.63-5.07) mu mol/mol creatinine for evening samples, and 1.94 (1.0 3-4.96) and 1.08 (0.49-5.05) mu mol/mol creatinine for morning samples. On the other hand, no significant difference in 1-OHP excretion was observed b etween the exposed and the control group (P >0.5). The respective geometric mean concentrations (5th and 95th percentiles) of 1-OHP for these groups w ere 0.05 (0.01-0.17) and 0.06 (0.01-0.48) mu mol/mol creatinine for evening samples, and 0.05 (0.02-0.12) and 0.05 (0.01-0.42) mu mol/mol creatinine f or morning samples. Conclusions: The measurement of alpha- and beta -naphth ol urinary concentrations appears to be an approach sufficiently sensitive to reveal differences in low exposure levels of volatile PAHs due to creoso te impregnation plant emissions. However, uptake of pyrene due to the plant was too small to contribute significantly to 1-OHP excretion.