URINARY 1-NAPHTHOL EXCRETION IN THE ASSESSMENT OF EXPOSURE TO CREOSOTE IN AN IMPREGNATION FACILITY

Objectives This study explored the possibility of using urinary I-naph thol excretion as a marker of complex exposure among workers handling creosote. Methods Urine specimens of 6 workers from a creosote impregn ation plant, where railroad ties were impregnated with coal tar creoso te, were collected during 1 workweek, and the concentration of I-napht hol was determined. l-Naphthol in spot urine samples of 5 occupational ly nonexposed male smokers was used as the background reference. Concu rrently, naphthalene and 10 different polycyclic aromatic hydrocarbons (PAH) were determined in personal air samples. Results The mean airbo rne exposure of the workers was 1.5 mg/m(3) for vaporous naphthalene, 5.9 mg/m(3) for particulate PAH and 1.4 mu g/m(3) for PAH with 4-6 aro matic rings. The mean urinary concentration of I-naphthol at the end o f the workshift was 20.5 (range 3.5-62.1) mu mol/l, whereas the refere nts' urinary concentration was below the detection limit (0.07 mu mol/ l). Airborne naphthalene correlated fairly well with l-naphthol when m easured at the end of the shift (r = 0.745). Conclusions This method o f analysis for 1-naphthol is sufficiently sensitive for measuring low occupational exposures to naphthalene. Low background exposures are, h owever: unlikely to result in detectable urinary levels of I-naphthol. Since naphthalene is the most abundant compound in creosote vapor, ur inary I-naphthol determination serves well as a biological marker of e xposure to vaporous creosote. Urinary l-naphthol alone is not, however , a suitable marker for inhalatory or cutaneous exposure to PAH origin ating from creosote.