The presence of 1-naphthol in the urine of industrial workers exposed to naphthalene.

Abstract

I-Naphthol at concentrations ranging from 0-4 to 34-6 mg/l was found in urine collected directly after the end of the work shift from a group of industrial workers employed in distillation of naphthalene oil. The maximum excretion was found one hour after the end of the shift and the mean excretion rate was 057 mglh. Coke plant workers exposed to naphthalene and other aromatic and polycyclic hydrocarbons also had 1-naphthol in their urine. Mean values were 0-89 mg/l (working with new technology) and 4-86 mg/l (working with old technology) and the excretion rates were 0-19 and 0*31 mglh respectively. The maximum excretion was shifted to two to three hours after the end of the exposure. For non-exposed subjects the mean urinary 1-naphthol concentration was 120 cggl and the excretion rate was 7*0 pglh. (Occup Environ Med 1994;51:357-359) l-Naphthol exists in animals as a metabolite of naphthalene.' It is excreted in urine as a sulphate or glucuronide conjugate.24 Keiser et al found l-naphthol in the urine of people exposed to the insecticide "carbaryl".'The presence of l-naphthol was earlier found in urine collected from workers before and after exposure and its excretion seemed to be slowed under conditions of simultaneous exposure to aromatic and polycyclic hydrocarbons.6 This study investigates the excretion of l-naphthol in more detail.

Urinary naphthols as an indicator of exposure to naphthalene

“…In an earlier study it has been shown that there is a good statistical correlation between 1-naphthol excretion and naphthalene exposure in the concelltration range of 0.2-6 mg/m3. This urinary metabolite can indicate exposure to both naphthalene and low concentrations of 1-naphthol during the naphthalene oil distillation process (15). Our study confirms a previous assumption that there is a correlation between the presence of naphthalene in air and the urinary excretion of 1-naphthol and 2-naphthol, which are two major oxygenated metabolites of naphthalene.…”

“…Investigations by Connor et a1 (28) have shown that smoking can contribute to the excretion of 1-naphthol in urine. Recent studies have demonstrated that the maximum concentration of 1-naphthol in the urine of operators working with the naphthalene oil distillation process appears 1 h after the end of a shift (15). The 1-naphthol concentration was the highest in the morning before the workday.…”

“…Increased urinary levels of 1-naphthol have been measured in several environments for iron foundry workers (IS), coke plant workers (15), and assemblers handling creosote-impregnated wood (16). This study aimed at identifying naphthalene homologues and urinary metabolites of workers exposed to naphthalene and investigating the relationship between exposure to naphthalene measured by personal air sampling and the excretion of 1 -and 2-naphthols in urine.…”

Excretion Profiles and Half-Lives of Ten Urinary Polycyclic Aromatic Hydrocarbon Metabolites after Dietary Exposure

“…A small number of studies have reported the elimination kinetics of urinary PAH biomarkers other than 1-PYR. The t 1/2 for 1-NAP was 4 h in workers conducting naphthalene oil distillation, 35 and 1.2-1.9 h and14-46 h (two-phase excretion) in 2 smoking workers. 36 Sobus et al collected pre-, post-shift, bedtime and morning samples from 20 asphalt pavers; the calculated half-lives were 26 h (95% CI: 14−116 h) for naphthols (summation of 1-NAP and 2-NAP) and 14 h (9.0-28 h) for phenanthrols (summation of 1-, 2-, 3-, 4-and 9-PHE).…”

Correlation of Environmental Carbaryl Measurements with Serum and Urinary 1-Naphthol Measurements in a Farmer Applicator and His Family

“…Although primarily associated with carbaryl elimination, urinary 1-naphthol is also attributed to naphthalene exposure, especially from cigarette smoke (14,15).…”