Temporal changes in urinary 1-hydroxypyrene concentrations in coke-oven workers

Coke-oven workers are exposed to high concentrations of coke-oven emissions, which are comprised mainly of polycyclic aromatic hydrocarbons. We conducted a pilot study to determine the time changes in urinary 1- hydroxypyrene (1-OHP) concentrations, as a metabolite of pyrene, in coke- oven workers after exposure to a benzene-soluble fraction (BSF) of total particulates. Thirteen subjects, including 2 men (referents) from an administrative area, 6 workers who work at the sideoven, and 5 who work on the top of the oven in one coke-oven plant were studied. After 1.5 to 2 days off, subjects were monitored individually for breathing zone air BSF over 3 consecutive days in August 1995. Seven spot urine samples, including preshift and postshift urine over 3 days and preshift urine on a fourth-day morning, were collected to determine 1-OHP concentrations by fluorescent spectrophotometry. The mean ambient BSF concentrations in the sideoven and topside oven workers ranged from 18 to 159 μg/m³ and from 251 to 1362 μg/m³, respectively, whereas the BSF concentrations in the referents were low but detectable (11 and 29 μg/m³). Urinary 1-OHP concentrations increased during the work period, from 10 ± 3 and 41 ± 9 μg/g creatinine (mean ± SE) on the preshift first day to 57 ± 26 and 334 ± 63 μg/g creatinine on the postshift third day in the sideoven and topside oven workers, respectively. However, the urinary 1-OHP concentrations were relatively fiat in the two referents. The across-shift change in urinary 1- OHP defined as postshift 1-OHP on the third day minus preshift 1-OHP on the first day was highly associated with individual mean occupational exposure to air BSF (r = 0.80, P = 0.001). Repeated-measures regression analyses revealed that daily postshift 1-OHP concentrations were marginally associated with daily air BSF. A 10-fold increase of daily air BSF resulted in a 1.67-fold increase of daily postshift 1-OHP levels (95% confidence interval = 0.99- 2.83; P = 0.07). After adjusting for daily preshift 1-OHP concentrations, we found that a 10-fold increase of daily air BSF resulted in a 1.90-fold increase of daily postshift 1-OHP levels (95% confidence interval = 1.10- 3.28; P = 0.03). Although the sample size is small in this study, these results indicate that daily postshift 1-OHP levels in urine are determined mainly by current occupational exposure to coke-oven emissions.