Urinary 1-hydroxypyrene concentrations in coke oven workers

Objectives - To investigate the relation of individual occupational exposure to total particulates benzene soluble fraction (BSF) of ambient air with urinary 1-hydroxypyrene (1-OHP) concentrations among coke oven workers in Taiwan. Methods - 80 coke oven workers and 50 referents were monitored individually for the BSF of breathing zone air over three consecutive days. Exposures were categorised as high, medium, or low among coke oven workers based on exposure situations. The high exposure group (n=18) worked over the oven. The medium and low exposure groups (n=41 and n=21) worked at the side of the oven for >4 hours and <4 hours a day, respectively. Urine was collected before the shift on the morning of day 1 and after the shift on the afternoon of day 3 to find the change of 1-OHP concentrations across the shift. Results - The median (range) changes of urinary 1-OHP concentrations across the shift for various exposure situations (μg/g creatinine) were as follows: high 182 (7 to 3168); medium 9 (-8 to 511); low 7 (-6 to 28); and referents 0.2 (-2 to 72). This change of urinary 1-OHP was highly associated with individual occupational exposure to the BSF in air (r = 0.74 and 0.64, p <0.001). The regression model showed significant effects of individual exposures to the BSF and alcohol consumption on urinary postshift 1-OHP after adjusting for preshift 1-OHP in the total population (n = 130). More exposure to the BSF led to higher postshift 1-OHP (p<0.001); current drinkers of >120 g/week had lower urinary postshift 1-OHP than never and former drinkers (p=0.01). A 10-fold increase in the average BSF in air resulted in about a 2.5-fold increase in postshift 1-OHP among the 80 coke oven workers. Conclusion - Urinary 1-OHP concentrations can be used as a good biomarker to assess individual exposure to the BSF in air. Alcohol drinking may modify the toxicokinetic pathway of the BSF; the effects of alcohol should be investigated further in occupational studies.